Three categories, one question

Every piece of equipment in the lab is Category 1, 2 or 3. The category answers one question: who has to be present before you switch it on?

Permission from an instructor is required in every case. What changes between categories is when that permission can be given, and who has to be in the room while the machine is running.

Category 1

Permission may be given in advance. Work alone once you have it.

Category 2

Permission at the time of use. A peer must be present throughout.

Category 3

Permission at the time of use. A peer and an instructor must be present throughout.

The category never removes a requirement. General safety procedures and PPE apply to every category, to every person present — see Equipment Operating Procedure and Personal Protective Equipment.

Category 1

• Can be used with instructor permission — may be given in advance or at the time of use.
• Can be operated independently, without peer or instructor supervision, once permission is granted.
• You must still follow all general safety procedures and PPE requirements.

Category 2

• Can be used with instructor permission — permission must be given at the time of use.
• Does not require instructor supervision during operation.
• Requires peer supervision present at all times during use.
• Both the operator and the peer supervisor must follow all safety procedures and PPE requirements.

Find the equipment category

These are the equipment categories for the Woods / Construction lab.

If an item is not on the list, ask the instructor to place it before you use it.

Category 1

• Hand tools (excluding saws)
• Paint / stain
• Sandpaper
• Glue
• Clamps

See Category 1 permission and supervision requirements before use.

Category 2

• Hand tools (saws)
• Power tools
• Belt/disk sander
• Drill press
• CNC router

See Category 2 permission and supervision requirements before use.

Category 3

• Table saw
• Band saw
• Miter saw
• Planer
• Jointer

See Category 3 permission and supervision requirements before use.

Find the equipment category

These are the equipment categories for the Rapid Prototyping Center.

If an item is not on the list, ask the instructor to place it before you use it.

Category 1

• 3D printers
• Hand tools (excluding knives)

See Category 1 permission and supervision requirements before use.

Category 2

• Laser cutter
• Hand tools (knives)

See Category 2 permission and supervision requirements before use.

Category 3

None.

See Category 3 permission and supervision requirements.

Find the equipment category

These are the equipment categories for the Metals lab.

If an item is not on the list, ask the instructor to place it before you use it.

Category 1

• Hand tools
• Fixture table
• Clamps
• Sanding / polishing
• Deburring kit
• Part setup

See Category 1 permission and supervision requirements before use.

Category 2

• CNC mill
• Drill press
• Belt/disk sander
• Grinder
• Power tools
• Waterjet

See Category 2 permission and supervision requirements before use.

Category 3

• Horizontal band saw
• Vertical band saw
• Manual mill
• CNC lathe
• Manual lathe
• Desktop injection molder

See Category 3 permission and supervision requirements before use.

During equipment operation

• Stay alert — maintain focus, and never leave equipment unattended while it is running.
• Follow proper procedures — use equipment only as trained and as intended.

Machine-specific hazards — pinch points, measurement, housekeeping — are covered in Machine Hazards and Housekeeping.

Personal Protective Equipment

Five topics. One of them — eye protection — applies the moment you walk in. The rest are set by what you are doing.

Eyes

Always, in the lab spaces. No exceptions.

Hearing

Prolonged exposure to loud equipment.

Feet

Closed-toe shoes, always.

Respiratory

Any grinding or sanding; hazardous dust or fumes.

Clothing & hair

Always, near anything that rotates.

Foot protection

• Minimum requirement: closed-toe shoes are MANDATORY — no sandals, no flip-flops, no open-toe footwear.

Recommended upgrades

• Slip-resistant soles, for traction on surfaces that may be slippery.
• Puncture-resistant soles, against sharp metal debris.
• Steel-toe or composite-toe protection — recommended, not required.

Avoid

• Canvas shoes or thin-soled footwear.
• High heels or unstable footwear.
• Anything that does not fully enclose your feet.

You will be standing for most of the lab period — choose something supportive and comfortable.

Hair, and what to wear instead

Hair

• Long hair must be secured back and kept away from equipment.
• Use hair ties, clips or caps to prevent entanglement.

Recommended

• Cotton or fire-retardant materials — preferred, not required.
• Close-fitting, short-sleeved shirts.
• Pants without excessive loose material.

Electrical Sources

What hurts you at 5 V is not what hurts you at 240 V; one is a burn hazard while the other is a shock hazard.

5 V / 12 V

The power supply on the bench, batteries, and the battery pack out of a cordless drill. Lower shock risk, not a magic cutoff. Not below the burn threshold.

120 V

Wall outlets. Dangerous — can cause serious injury or death.

240 V / 480 V

Industrial equipment. Extremely dangerous — often fatal.

What is a Safety Data Sheet (SDS)?

A Safety Data Sheet is the manufacturer's written answer to what their product can do to you, what to wear, and what to do when it goes wrong.

There are sixteen sections, always in the same order. You do not need to read a SDS front to back but you should read the following three sections before you use a product.

Section 2

Hazard(s) identification. What the chemical can do to you, in the manufacturer's own words — a signal word, the hazard statements, the red-bordered pictograms.

Section 4

First-aid measures. On skin, in eyes, breathed in, swallowed.

Section 8

Exposure controls / personal protection. Gloves, eye protection, ventilation — the PPE answer for that specific chemical, rather than the general one.

None of this is a local rule. OSHA requires a sheet for every hazardous chemical, and requires the sixteen sections and the order they come in — 29 CFR 1910.1200(g).

Supporting detail: Addendum 3 — All sixteen sections, and the four OSHA does not enforce.

Supporting detail: Addendum 4 — Signal words, pictograms and H-numbers — how Section 2 is written.

Where is SDS binder located?

• All Safety Data Sheets are organized in a designated binder for easy reference.
• Review before use — check the sheet for any unfamiliar chemical or liquid.
• Ask the instructor if you cannot locate the sheet for a material.

The binder is one way of satisfying the rule underneath it. 1910.1200(g)(8) requires an employer to keep the sheets "readily accessible during each work shift to employees when they are in their work area(s)", and allows electronic copies in place of paper "as long as no barriers to immediate employee access in each workplace are created by such options." Binder or screen, the test is the same: the sheet is something you can reach now, not something you have to go and ask for.

Supporting detail: Addendum 5 — Telling a current sheet from an old one.

Material Storage and incompatible materials

• Flammable liquids must be stored in an approved flammables cabinet when not in use.
• NEVER store incompatible chemicals together.
• All containers must be properly labeled.

“Incompatible” is not a judgement call, and answering it needs no chemistry. It is written on the sheet, by name, in two places:

Section 10

Stability and reactivity. One of its required entries is "incompatible materials" — what this chemical must not contact. Beside it sit "conditions to avoid" and "hazardous decomposition products", which is what the two of them would make.

Section 7

Handling and storage. Required to give "conditions for safe storage, including any incompatibilities" — the same question answered for the shelf rather than for the reaction.

So the test before two things share a cabinet: open both sheets and read Section 10 on each. The entry may name a specific substance or a whole class of them — oxidizers, strong acids. If either sheet names the other material, they do not go together. Read both, because the pair may only be called out on one of them.

Fumes and dust have a PPE requirement of their own — see respiratory protection.

Supporting detail: Addendum 6 — What makes a flammables cabinet “approved”, and how to spot one.

The environment around the machine

Slip hazards

Clean dust, metal chips, water and coolant off the floor immediately.

Lighting

Ensure lighting is adequate before operating any machine.

Walkways

Keep aisles and emergency exits unobstructed.

Operating habits

• The chuck key never leaves your hand. It is not released until it is out of the chuck. There is no moment where the key is in the chuck and not in your grip — not to reach for something, not to answer someone, not for a second.
• Stop machines completely before taking measurements or making adjustments.
• Secure all workpieces before operation — use clamps, vises or fixtures.
• Never leave tools on or near operating machinery.

Supporting detail: Addendum 12 — Why the chuck key rule is worded as a grip and not as a reminder.

The shutdown and cleaning steps that close every session are in After operating any equipment.

Using an extinguisher — PASS

Remember the acronym: P–A–S–S.

When it looks out, back away watching the fire, exit behind you. Do not assume it is over — a knocked-down fire can reignite.

Fire classes, and what puts them out

Fires are classed by what is burning. An extinguisher is rated for the classes it can handle, and using the wrong one ranges from useless to dangerous.

Most extinguishers on a wall are ABC dry chemical — one unit covering the first three classes. Check the label; the classes it is rated for are printed on it.

Hot work and the things that start fires

• Grinding throws sparks a surprising distance. Clear rag, sawdust, solvent and packaging out of the area before you start, not after it smolders.
• Oily rags — it depends entirely on which oil. Drying oils — linseed, tung, oil-based stains, varnishes and finishes — cure by reacting with oxygen, and that reaction gives off heat. Bunched in a pile the rags hold the heat in, and the pile can reach ignition on its own with nothing to light it. Those rags NEVER go in a pile: spread them flat to dry, drop them in water, or use the designated container.
• Petroleum oils do not do that. Way oil, cutting fluid, hydraulic oil and ordinary shop oil do not cure by oxidation, so a rag wiped with them will not self-heat and will not spontaneously combust. It is still combustible — a spark or a hot chip will light it like any oily cloth — so keep it away from hot work and out of a bin of paper or sawdust. If you do not know which oil is on the rag, treat it as a drying oil.
• Flammable liquids live in a flammables cabinet when they are not in your hand — see Chemicals and Safety Data Sheets.
• A smoldering fire can restart long after you leave. If something got hot enough to smoke, tell the instructor before you go.

Four reasons a chip is dangerous

A chip is not scrap until it has cooled and stopped moving. Straight off the tool it is every one of these at once.

Hot

Where an aluminum chip forms, the cut runs roughly 250–650 °C (500–1200 °F), depending on the alloy and the speed. Chips do not look it.

Sharp

The leading edge of a chip is always razor sharp. It is a freshly cut edge and it will open a hand.

Strong

A long continuous chip is a steel ribbon. If it wraps a sleeve or a limb it can pull you into the machine.

Slippery

Chips on the floor roll underfoot. This is one of the most common ways people get hurt without the machine touching them.

Staying alert

• Stay focused — maintain concentration while operating equipment.
• Take breaks when tired or distracted.
• Ask questions if you are unsure about any procedure.
• Report unsafe conditions immediately to the instructor.

Workspace responsibility

• Clean as you go — do not wait until the end.
• Report equipment problems before they become safety hazards.

Why 5S sits in a safety module

5S is a lean manufacturing method for organizing a workplace. It earns its place here because most of what it asks for is also what keeps people from getting hurt.

A cluttered bench hides a hazard. An unlabeled container is an unknown chemical. A floor with chips on it is a slip. Every one of those is a 5S failure before it is an incident — which is why the shutdown steps in After operating any equipment are 5S in everything but name.

This page is the basics. 5S will get its own expanded treatment later.

Sort — Seiri

• Separate necessary items from unnecessary ones.
• Remove or relocate items that do not belong in the work area.
• Keep only what you need for the task in front of you.

Set in Order — Seiton

• Organize and label the remaining items clearly, for easy identification.
• A place for everything, and everything in its place.
• Create logical, efficient storage systems.

Shine — Seiso

• Clean work areas to maintain high hygiene standards.
• Reduce accident risk through cleanliness and organization.
• Inspect while cleaning — that is how problems get found early.

This is the step that overlaps most directly with safety — see the environment around the machine.

Standardize — Seiketsu

• Establish consistent procedures for maintaining the first three S’s.
• Create habits through regular practice and routine.
• Ensure everyone follows the same organizational systems.

Sustain — Shitsuke

• Continuously review and maintain all 5S practices.
• Build the discipline to follow established procedures long-term.
• Regular audits, and improvements to the system itself.

3D printers: Category 1 in the Rapid Prototyping Center

These printers build parts from filament, layer by layer. See 3D Printing from CAD for preparing a model and FDM 3D Printing for the printing process.

Category 1 in the Rapid Prototyping Center. Use Equipment Categories and Supervision for permission and supervision. General checks and protective equipment are in Equipment Operating Procedure and Personal Protective Equipment.

Get the project and material approved before printing

In our labs, a DET faculty member must approve a 3D-printing project before it starts. A project assigned by DET faculty needs no separate project approval, but must stay within its own guidelines and all RPC rules.

For approval, explain what the item is, where its design came from, how it will be made, the material amount and source, and its intended use; supply the digital file through the instructor's designated channel.

• No personal material without prior approval.
• No weapons, weapon-like items, weapon components, ammunition, dangerous materials or drug paraphernalia.
• No commercial use. Class projects take priority over personal projects.

Hot surfaces and moving parts remain hazards during remote printing

The nozzle and heated bed can burn, including after motion stops. Let them cool before handling the finished print or build plate. Keep hands and tools out of the printer's moving area; use Machine Hazards and Housekeeping for the general movement and isolation rules. See Prusa's hot-part precautions for further reading, not permission to service lab equipment.

The lab guide uses Prusa Connect or its app to monitor progress. A remote status display does not replace the physical readiness check. Set Ready can release the next queued job, so use it only after checking the machine and clearing the work area.

When your print is finished and safe to handle, remove it, check the plate and material again, and set the printer ready for the next job. Remove scrap and purged filament, return tools and leave the work area tidy.

Report jams and faults; do not repair the printer yourself

In our labs, report jams, malfunctions and other technical problems to DET faculty. Do not try to fix equipment yourself. Stop a failing print using the controls covered in your training, and do not set a faulty printer ready for another job.

The student guide permits resetting an offline printer only when it is not currently in use. If you cannot establish that, or if a fault remains, report it rather than repeatedly resetting. Use Lab Conduct and Emergencies for an injury or emergency.

Read the pattern before deciding what the line means

Every line on an engineering drawing has a job. Some describe the part; others tell you how to measure it, where to look, or how a view was made. Treating every line as a physical edge gives you the wrong part.

Use three clues together: pattern (solid or dashed), weight (thick or thin), and context (arrows, letters, numbers, and nearby features). A thin solid line alone could be a dimension, an extension, a leader, or section hatching.

Visible and hidden lines describe edges; center lines locate axes

Visible / object

A relatively thick, continuous line shows an edge or outline you can see from this viewing direction.

Hidden

A thin series of short, evenly spaced dashes shows an edge concealed by material. A hole may appear as a visible circle in one view and two hidden lines in another.

Center

A thin long-short pattern locates a center, axis, or symmetry reference. The center line through a cylinder is not a seam in the cylinder.

Phantom

A thin long-short-short pattern can show an alternate position, repeated detail, or a nearby part used as a reference. An open position of a lever does not mean there are two levers.

Read all views together. A line's visibility depends on where you are looking from. The same edge can be solid in one view and dashed in another.

Arrows, notes, and hatching tell you what to do with a view

Dimension

A thin line with arrowheads identifies the extent of a measurement. Read the associated value; do not measure the picture on your screen.

Extension

A thin line carries a feature's location out to a dimension line. A small gap usually separates it from the part outline.

Leader

A thin line connects a note to the feature it describes, usually with an arrow at an edge or a dot on a surface. Follow it to its endpoint.

Cutting plane

A prominent line marks an imaginary cut used to expose the interior. Read its arrows for the viewing direction and its letters to find the matching section, such as A–A. The line pattern can vary; arrows and identification matter.

Section / hatch

Thin parallel strokes inside a section view identify material crossed by the imaginary cut. They are not grooves machined into the part.

Break

A short freehand break or a long thin line with zigzags marks an omitted portion of a view. The actual part is not necessarily broken; a long uniform member can be shortened on paper while its dimension gives the full length.

For units and decimals, use Measurement Language. For allowable variation, use Tolerances and Fits. Creating the dimension callouts comes next in Drawing Dimensioning.

When lines coincide, do not invent a second feature

Where a visible edge and a hidden edge project to exactly the same place, read the visible line. Where a hidden edge and a center line coincide, read the hidden line; the center line may still be identifiable where it extends beyond the edge.

A crossing is different from an overlap. Two lines crossing on the sheet do not prove that two physical edges meet in space. Check another view before deciding.

Supporting detail: Addendum 14 — Why context matters more than one dash.

Practice identifying lines

Each view looks straight at the part from one direction

A pictorial helps you recognize a part. A multiview drawing helps you describe its shape without the apparent shrinkage of perspective. In orthographic projection, the lines of sight are parallel and perpendicular to the viewing plane.

Choose a front direction and keep the part fixed. Look straight from the front, from above, and from the right. Do not turn the part independently to make each view look convenient.

Front and rear

Show width and height; depth points toward or away from you.

Top and bottom

Show width and depth; height points toward or away from you.

Right and left

Show depth and height; width points toward or away from you.

A face parallel to its viewing plane shows its true shape at the drawing's scale. A face tilted to that plane is foreshortened; a face viewed exactly edge-on becomes a line.

The glass box unfolds into six related views

Imagine the part inside a transparent box. For third-angle projection, trace what you see onto the box face between you and the part. Each face receives one principal view: front, rear, top, bottom, left, and right.

The names identify the direction you look from. A right-side view means you stood at the part's right, even if a different projection convention puts that view elsewhere on the sheet. Compare First-Angle and Third-Angle Projection.

Match the pictorial to its front, top, and right views

Identify each numbered candidate using the viewing directions on the pictorial. These candidates are arranged as answer choices, not in a first-angle or third-angle layout.

Use the self-checks to test your choices and read the explanations.

Identify the front Identify the top Identify the right

Drawing views describe one part from different directions

A drawing view is a flat picture of a part seen from one direction. A set of views, read together with dimensions and notes, describes one three-dimensional part so someone can make or inspect it.

A front view shows width and height. Looking from above or from the side can show the front-to-back depth that the front leaves out. In this stepped-block example, the front explains the step heights, while the top shows how far the block extends back.

Choosing views means selecting the directions that explain the shape clearly. Orthographic Projection explains how the views line up and how their positions tell you the viewing direction.

Choose the front view that explains the shape

The front view is a drawing of the part from the direction chosen as the starting point for the other views. The side shown need not be the one that happened to face you when you picked up the part.

Start with a stable, understandable orientation. Prefer a view that shows characteristic shapes directly and keeps important features out of hidden lines, the dashed lines used for edges blocked from sight. For a stepped part, a profile that shows the steps is usually more useful than a plain rectangle.

The front, top, and side are principal views: views along the part's main directions. Once the front is chosen, the other principal views follow from it. Keep their orientation and alignment consistent with Orthographic Projection and the Glass Box.

One or two views can be enough when the missing information is stated

One view

A flat plate with a constant thickness can be defined by its face view and a thickness note, provided the outline, holes, and other requirements are completely specified. A circle alone does not say whether the part is a disk, a sphere, or a cylinder.

Two views

A constant-depth stepped shape can use a profile and a top view to establish the step widths, heights, and front-to-back depth. A third view may add no new information. A simple cylindrical part can often be described with a side view and an end view.

Three views

Front, top, and a side view are useful when features change across all three directions. Each view should resolve a question the others leave open.

Three is a common arrangement, not a quota. Dimensions, notes, symmetry, and repeated geometry can supply information without drawing every side. The remaining views and written requirements must still define the whole part.

Add a view when it removes a real ambiguity

A view is useful when it answers a question the existing views leave open. For example, the same circular front outline could belong to a thin disk or a long cylinder. A side view or a length note can resolve that difference. If two different parts still fit the drawing, identify the missing information and add the view or written callout that separates them.

Hidden interior

A section view can expose a bore or recess more clearly than a tangle of dashed lines. Its cutting-plane arrows tell you which way to look.

Flat sloping surface

An auxiliary view looks straight at the surface from an extra direction so its shape is clear. Another front, top, or side view may still make it appear shortened. See Auxiliary and Detail Views for that construction.

Small feature

An enlarged detail view makes a crowded feature readable. Read its stated scale; do not compare its apparent size directly with the main view.

Supporting detail: Addendum 16 — Why more pictures do not automatically mean more information.

Check the projection convention before naming a side view

First-angle and third-angle projection can show the same part from the same directions. What changes is where those views are arranged on the sheet.

Look for the projection symbol or an explicit note, often near the title block. Use it with the view labels. If the symbol and the views disagree, resolve the inconsistency before interpreting the part.

A right-side view is always the view from the part's right. In first-angle projection, it sits to the left of the front view. Do not rename it a left-side view because of its position.

The projection symbol is two views of a shortened cone

The trapezoid is the side view of a cone with its tip removed, called a frustum. The two concentric circles are its end view. Their arrangement tells you which projection method is being used.

Supporting detail: Addendum 17 — Use the glass box to explain the swap.

Expect third-angle on U.S. mechanical drawings, then verify it

Third-angle is the usual U.S. mechanical drawing convention. A shared convention lets the designer and the person making or inspecting the part interpret the layout the same way. It is a communication choice; neither method changes the part's geometry.

The drawing's declared convention is the deciding information. Country of origin, inch units, or a familiar company name is not a substitute for checking. Drawings cross borders, and CAD templates can use different defaults.

Supporting detail: Addendum 18 — A documented U.S. example, with its scope.

Use the view explorer to switch layouts while holding the part fixed. Then work through the projection self-check.

Sketch the idea before committing to CAD

A quick hand sketch lets you compare shapes, explain an idea, and find missing information before building a CAD model. Aim for a readable shape and sensible proportions. A sketch does not need mechanically perfect lines to be useful.

Use a pencil, eraser, and plain or grid paper. Isometric paper can help keep the three directions consistent. Start lightly so you can revise; darken the visible edges only after the overall form works. Add small features last.

Label important features and write any known dimensions. Do not expect someone to recover an exact size by measuring your freehand sketch. For line meanings, see The Alphabet of Lines. CAD sketch tools are covered separately in Sketch Entities and Planes.

Isometric sketches use three equally spaced directions

Draw one axis vertically and the other two down to the left and right, each 30° from horizontal. The three outward rays are 120° apart. Edges parallel to these axes keep those directions throughout the sketch; they can extend either way along each axis line.

Use the same scale along all three axis directions. Lay out width, height, and depth along lines parallel to the axes; an isometric grid helps you keep equal intervals consistent.

Supporting detail: Addendum 19 — Isometric drawing and isometric projection use different scales.

For CAD view types, see CAD Model Views and Checks.

Locate sloping edges by endpoints; sketch circles as ellipses

A non-isometric line is not parallel to any of the three isometric axes. Locate both endpoints using width, depth, and height offsets, then join them. Do not lay the true sloping-edge length directly along its apparent direction on the paper.

For a circle on a face parallel to a principal plane, first sketch its enclosing square as an isometric rhombus. Mark the four side midpoints and sketch a smooth ellipse tangent there. Those are contact points, not sharp corners. Keep the curve inside the rhombus.

The circle-to-ellipse rule here applies to circles on the usual top, front, or side planes of the isometric sketch. Do not draw a round circle on one of these tilted faces.

Choose isometric for three directions or oblique for a true front face

In an isometric sketch, the three principal directions share one scale, and none of the three principal faces appears in true shape. In an oblique sketch, draw the chosen front face in true shape at the drawing scale, then carry parallel edges back along one receding direction.

A 45° receding direction is common, but it is not required. Full-scale depth is called cavalier; half-scale depth is called cabinet. Keep the chosen depth scale consistent. A circle on the oblique front face stays circular; one on a receding face generally does not.

Both methods use parallel edges rather than perspective vanishing points. Pick the front direction deliberately; see Choosing Drawing Views.

Identify a pictorial Find a non-isometric line Check a circle sketch

Match a surface by its boundaries, not its apparent shape

Face A in this original example is the front face. Face B is the sloping face made by removing a corner through the full depth. Follow their corner positions and shared boundaries across the views.

A appears in true shape in the front view. From above, all its points have the same front-to-back position, so it collapses to the front boundary line. From the right, it also appears edge-on. B appears as a sloping edge in front, but as a foreshortened area in top and right.

Supporting detail: Addendum 20 — One drawn line can represent several boundaries.

Normal, inclined, and oblique describe a flat surface relative to the view planes

Normal surface

Parallel to one principal projection plane and perpendicular to the other two. It shows true shape in one principal view and an edge in the other two. Face A is an example.

Inclined surface

Perpendicular to one principal plane and tilted to the other two. It shows an edge in one principal view and a foreshortened area in the other two. Face B is an example.

Oblique surface

Tilted to all three principal planes, with none parallel or perpendicular to it. It shows a foreshortened area in all three principal views; none shows true shape or an edge view.

Here “oblique surface” describes a face orientation. “Oblique sketch” describes a pictorial drawing method. A part with an inclined face can be drawn with either isometric or oblique sketching.

Turn a pictorial back into views one direction at a time

Keep the front direction fixed. For the front view, discard depth and plot width against height. For the top, discard height and plot width against depth. For the side, discard width and plot depth against height. Include changes of surface inside the outside outline.

Before checking, explain which boundary remains visible from above and where it lies relative to the width. A matching outside rectangle alone is not enough.

Match the top view Find an edge view Classify a surface Recognize an oblique surface

Use an imaginary cut to expose the interior

A section view shows what is inside a part without making you untangle a group of hidden lines. Imagine cutting the part, removing the material between you and the cutting plane, and looking at what remains.

The cut changes the drawing representation, not the manufactured part. Hatch the material crossed by the plane and show the useful visible edges beyond it. Hidden lines are usually omitted in sections unless needed to make the shape clear.

Start with The Alphabet of Lines and Orthographic Projection and the Glass Box if the line types or viewing directions are unfamiliar. For a sloping face or a small feature, see Auxiliary and Detail Views.

Full sections cut all the way through the part

A full section uses one plane through the entire part. For this hollow cylinder, a plane through the axis exposes both walls and the bore. The bore is empty space and receives no hatching.

Half sections combine the exterior and interior

A half section is useful for a symmetric part. Imagine removing one quarter with two perpendicular cutting planes. The resulting view shows one half in section and the other half as an exterior view, usually divided by a center line.

It is not a full section with half its hatch erased. The unsectioned half shows the outside, and symmetry supplies the connection between the two halves.

Offset sections reach features that are not in one straight line

An offset section jogs the cutting plane to pass through several features. Project the selected parallel portions into one section. The jogs help explain the cut location; they do not create physical edges on the part.

Read the parent view for the holes’ actual locations. Their appearance together in the section does not mean they lie in one straight row.

Broken-out sections expose only a local area

A broken-out section removes a limited patch to a chosen depth in an existing view. An irregular break line marks the boundary. Use it to expose a small passage or wall without adding a complete section view.

A separate cutting-plane line is normally unnecessary: the local boundary identifies the area. Depth still matters; a cut that stops before a bore will not reveal it. This differs from a broken view, which merely shortens a long part on the sheet.

Revolved sections show a cross section in place

A revolved section turns a cross-sectional slice 90° into the plane of the drawing and places it on the parent view. It is useful for the shape of a bar, spoke, or arm. Show the slice itself, rather than the features behind the cut.

Removed sections place the slice clear of the parent view

A removed section places the cross section away from the parent view to keep it readable. Match its identifying letters to the cutting plane. Several removed sections can describe changes along a long part; keep each location unambiguous.

Aligned sections rotate an angled portion into the section plane

An aligned section uses intersecting cutting planes through features arranged around an axis. An angled portion is rotated into alignment before it is shown in the section. This makes radial features easier to read.

Do not infer angular spacing from the aligned result. In this disk, one small hole is rotated into the section plane; its original angular position is established by the top view.

Hatch cut material, with conventional exceptions

Use thin, evenly spaced diagonal lines, commonly near 45° to the main outline. Change the angle when the hatch would be confused with an edge. Keep a part’s hatch consistent; distinguish adjacent assembly parts by changing hatch angle or spacing.

• Voids: holes and open spaces are never hatched as solid material.
• Ribs, webs, and spokes: a cut along their length generally leaves them unhatched so they do not look like a thick solid wall. A transverse cut through their thickness is hatched.
• Shafts and fasteners in assembly sections: when cut lengthwise through their axes, solid shafts, bolts, nuts, washers, pins, and similar standard parts are commonly shown unsectioned. A transverse shaft section can be hatched; “never hatch a shaft” is too broad.

An unhatched region may be empty space, an uncut surface, or a conventionally unsectioned component. Use its outline and the other views to decide which.

Supporting detail: Addendum 22 — Drawing standards and scope.

Extra views make sloping surfaces and small features easier to read

An auxiliary view is an extra drawing view that looks straight at a flat, sloping surface so its shape is clear. A tilted rectangular surface can look shortened from above; looking straight at it reveals its rectangular proportions.

A detail view is an enlarged picture of a selected small region, such as a hole with crowded edges or dimensions. The actual part stays the same size. Use an auxiliary when the viewing direction makes the shape hard to read, and a detail when a small region needs more room.

A view's scale tells you how large its picture is compared with the real part. Read the view labels and scale information to connect an added view to the original drawing. To expose an interior hidden behind solid material, use a section view.

Look perpendicular to a face to see its true shape

A face is a surface on the part. Look straight at a flat face, perpendicular to it, to see its true shape. In projection terms, that face is parallel to the imaginary flat surface on which the view is drawn: the projection plane.

In the figure, the part is a wedge with a flat, sloping rectangular face. The front view sees that face edge-on, so the face is reduced to the line P–Q. The light-blue rectangle is the same face viewed straight on in the auxiliary view.

In this example, the front view sees the inclined face on edge. The top view shows it foreshortened: its sloping length appears shorter because the view is not looking straight at the face. The top view's 160-unit length is not the face's true 200-unit length.

Scale is the ratio of a length on the drawing to its actual length. “True shape” still allows the stated drawing scale; it does not mean the image must be life size. The auxiliary view shows the face's correct proportions without the shortening caused by the viewing direction.

A primary auxiliary view is constructed directly from a principal view, such as the front, top, or side. Choose its projection plane parallel to the inclined face. Review Orthographic Projection and the Glass Box and Choosing Drawing Views for the principal views.

Supporting detail: Addendum 24 — When one auxiliary view is not enough.

A detail enlarges a feature; a break shortens the view

The existing view from which a detail is taken is its parent view. A boundary and letter usually identify the selected region. In the figure, the circle marked B locates the region shown in Detail B.

Match the detail label and read its scale. 2:1 means a drawn length is twice the actual length; the hole itself has not grown. Enlargement alone does not change the viewing direction or reveal hidden features.

A broken view omits a middle length of a long, substantially uniform part so its ends and features fit on the sheet. Break lines identify the omission. The actual part remains continuous, and dimensions across the break state its full size. Use those dimensions rather than measuring the shortened illustration.

A broken view is different from a broken-out section, which shows interior geometry by representing a local portion of material as removed. See Section Views.

Project from the edge view and transfer the missing depth

The auxiliary figure above uses the front view as its parent. Its thin projectors are construction lines used to line up corresponding points in the two views.

1. Find the principal view in which the face is a line. In the example, the front view shows the sloping face edge P–Q.
2. Draw a fold or reference line parallel to P–Q. It represents the hinge between the parent and auxiliary projection planes.
3. Draw thin projectors perpendicular to the fold line from the face’s corners.
4. Transfer each corner’s depth from the corresponding principal view, using the same reference and drawing scale. Here the top view supplies a constant depth of 80.
5. Connect corresponding points. The face is a 200-by-80 rectangle in the auxiliary view, although the top view shows its sloping length shortened to 160.

These are invented drawing units for the construction. The projectors and fold line are not physical edges on the part. The auxiliary view shows this face's true shape, not necessarily the true shape of every other face.

Use a partial auxiliary view when only one face matters

A partial auxiliary view shows the useful inclined face and enough nearby geometry to identify it. Omit unrelated geometry that would make the view crowded, using an appropriate break boundary where the view is interrupted.

Keep the viewing reference, label, and scale clear. Partial means limited coverage; it does not change the projection direction. The construction above isolates the inclined face for that reason.

Create auxiliary, detail, and break views from the parent in CAD

Auxiliary view

Select the parent and a reference edge representing the inclined face edge-on. Use Auxiliary View in SOLIDWORKS or Auxiliary view in Onshape, check the direction, and place the view. For a partial view, limit the displayed region with the application’s crop or partial-view controls while retaining identifying references.

Detail view

Use Detail View in SOLIDWORKS or Detail view in Onshape. Define the region, place the enlarged view, and set its scale and label. Verify that dimensions reference the intended model edges.

Broken view

Use Break View in SOLIDWORKS or Break view in Onshape. Choose break direction and style, then position the two break boundaries. Check that no feature needed to define the part was omitted.

Review the result after every model revision. A generated view can be geometrically valid yet omit the feature the reader needs.

Supporting detail: Addendum 25 — Vendor help and dimensioning references.

Practice choosing the true-shape view Practice reading a broken view

A dimension connects a number to a specific feature

A drawing shows the shape. Its dimensions tell the reader how big the features are and where they belong. Read the stated value; do not measure the picture.

Dimension line

Runs in the direction being measured. Its arrowheads mark the extent of the dimension.

Extension line

Projects an edge, center or other point out to the dimension. Leave a visible gap at the part and continue a little beyond the last related dimension line.

Arrowheads and text

The arrows identify the endpoints; the text gives the value and any needed symbol. Use a consistent arrow style and readable text size.

Leader

A thin line connecting a note or callout to its feature. A hole leader ends with an arrow on the circle, directed toward its center.

Keep the dimension line separate from the part outline. A visible edge or centerline is not a substitute for a dimension line. For line types and views, see the Engineering Graphics collection’s Reading Drawings group.

Put dimensions outside the view, with the shortest nearest the part

Keep the outline clear. Put short dimensions close to the view and longer dimensions farther out. This also reduces the number of extension lines that cross dimension lines.

A dimension inside the view can be appropriate when it is clearer there or avoids an excessively long leader. The aim is clarity, not an empty interior at any cost.

Leave room for the lines, arrows and text

Use at least 10 mm from the part outline to the first dimension line and 6 mm between successive parallel dimension lines as layout guides. Those are distances on the drawing sheet, regardless of the part’s scale. The familiar inch drafting guides are about 3/8 in and 1/4 in; they are rounded guides, not exact conversions.

Keep the gap at the part visible and extend the extension line slightly beyond the dimension line. About 2 mm of overrun is a useful drafting target. Increase spacing when the annotation needs more room.

Supporting detail: Addendum 26 — Which parts are standards, and which are layout guides?.

Keep text readable from the bottom of the sheet

Use unidirectional text for the ordinary linear dimensions here: the numbers read from the bottom even when the dimension line is vertical. Leave clear space around the number. On a horizontal line, the text may sit above it or in a break in it.

Stagger values on several parallel dimension lines so they are easier to separate. Keep lettering free of part outlines, extension lines and leaders.

Supporting detail: Addendum 27 — Why older drawings may look different.

Rearrange crossing lines before accepting clutter

Move dimensions or notes to avoid crossing dimension lines, extension lines and leaders wherever practical. Keep a leader short, with a clear arrow target and a short horizontal landing next to the note.

If extension lines must cross, normally leave them continuous. Do not introduce gaps that make their endpoints ambiguous. A break near an arrowhead can preserve its readability.

Next: choose the information the drawing needs. Practice placement

Ask what information is necessary to make this part

Start with the geometry, not with the dimension tool. Break the part into familiar forms: blocks, cylinders, holes, steps, slots and arcs.

Size dimensions

Describe the feature itself: a block’s length, width and thickness; a hole’s diameter; a slot’s width and length.

Location dimensions

Place that feature relative to other features or a chosen origin. A hole diameter alone does not say where the hole goes.

Locate a round hole by its center, not by a tangent edge that moves when the diameter changes. Choose reference surfaces that make sense for how the part fits and is checked. A formal datum has a specific meaning in geometric tolerancing; an arbitrary sketch origin is not automatically a datum.

Dimension a feature in the view that shows its shape

Contour dimensioning keeps a feature’s dimensions with the view where its outline is clearest. Put a hole size on a view showing its circle. Put a step’s height where the step is visible. Use a section or another suitable view for an internal feature.

For the beginner drawings here, do not dimension to hidden lines: choose a view that exposes the feature. Keep the dimensions of one feature together when practical. See the Reading Drawings group in Engineering Graphics for projection, section views and view selection.

Give each independent requirement once

Completeness means every feature is defined. It does not mean every possible distance is dimensioned. A feature may need several dimensions, but the same size or location requirement should not be repeated in another view or restated by a closed chain.

A closed chain gives all the segments and their total as controlling dimensions. Remove one link, or make a useful derived value a reference dimension. Which link to remove depends on what the part must do.

Supporting detail: Addendum 28 — Why nominal arithmetic is not enough.

Parentheses mark information, not an extra acceptance requirement

A reference dimension is shown in parentheses, such as (1.50). It helps the reader without imposing another manufacturing or inspection requirement. Use one when the derived value is useful; leave it out when it only adds clutter.

In the two-hole example, .80 and 2.30 can control the centers while (1.50) reports their nominal spacing. Parentheses do not mean that the physical distance cannot vary.

A basic dimension, shown in a rectangular box, is different: it supplies a theoretically exact value for a geometric tolerance scheme. It does not demand a physically perfect part. See Tolerances and Fits before interpreting limits or fits.

Find a redundant dimension Count the required dimensions

Read the units before reading the numbers

Find the drawing’s unit note or title block first. On an inch drawing, .625 means 0.625 inch, not 625 inches and not millimeters. The unit need not be repeated beside every value when the drawing states it.

Decimal-inch dimensions conventionally omit the leading zero below one inch. Keep trailing zeros: .50 and .500 have the same nominal size, but may select different rows in the drawing’s general tolerance block. There is no universal “three decimals means ±.005” rule; read the actual block and any local tolerance.

An angle still needs its angle notation: 90°. Mixed units must be identified. For units and precision, use Measurement Language; for tolerance values, limits and fits, use Tolerances and Fits.

Use a diameter for a full circle and a radius for an arc

⌀ before a value means diameter. R before a value means radius. Thus ⌀.60 describes a full circular diameter of .60, while R.30 describes an arc radius of .30. The values are related, but the callouts describe different kinds of feature.

n X means the requirement applies in n places. A repeated size still needs an unambiguous pattern: center coordinates, spacing, or a fully defined bolt circle. A sketch that merely looks evenly spaced is not enough.

A round-ended slot needs size, location and direction

For a straight slot with semicircular ends, give its width and either its overall length or the distance between the end centers. Make the chosen meaning clear. Then locate the slot and establish its direction relative to the part.

Do not control the width, end radius, center spacing and overall length all at once. That repeats the relationships already built into the semicircular-ended shape. If a slot is not semicircular-ended, this shortcut does not apply.

Read a hole callout from the main hole to the added recess

The first size usually describes the main hole. Read the remaining symbols with the values immediately following them. All examples below are invented decimal-inch teaching values.

Read the leader and section view to identify the entry side. A hole callout supplies size and end condition; it still needs location dimensions. A countersink angle is not automatically 90°.

A spotface provides a local flat seat

A spotface provides a flat circular seating surface around a hole. Its modern symbol puts SF inside the counterbore-shaped mark. Older drawings may use the counterbore mark with a note or context identifying the spotface.

A spotface may have a stated depth or remaining material thickness. If neither is specified, the ASME convention is the minimum depth needed to clean up the specified diameter. Do not invent a depth from the sketch.

Supporting detail: Addendum 29 — Reading old and new symbol styles.

Choose a graphic for the question you need to answer

Engineering graphics communicate technical ideas and problem solutions. Aim for accuracy, simplicity, and clarity. A graphic succeeds when another person can use it for the intended task.

Ideation sketch

A quick drawing for exploring and comparing ideas. Designers and teammates use it to discuss shape, motion, or arrangement before committing to detailed geometry. Label uncertain sizes and assumptions.

CAD model

A digital description of geometry. Designers use it to develop parts, examine how components fit, and support analysis or manufacturing preparation. A realistic appearance alone does not prove that the design works.

Engineering drawing

Selected views with dimensions, tolerances, and notes. People making, assembling, and inspecting the product use this information to understand what is required. See Working Drawings and Title Blocks.

Choose a graphic for brainstorming

Use testing to send the design back for refinement

Begin with the task and its requirements: what must the design do, and what limits must it satisfy? Sketch alternatives, develop promising geometry, then test it against those requirements. Testing may involve calculations, simulation, a prototype, or a combination.

When a test reveals a problem, revise the design and test again. Update the affected graphics so that the model, drawings, and test record describe the same design.

Supporting detail: Addendum 30 — Why the process is a loop.

Choose a graphic for a fit review

Release identifies the information approved for use

Release means approving a defined design state for its intended use through the organization's review process. Before release, check the model, drawing set, and supporting requirements together. A saved file is not automatically an approved file.

A maker needs part requirements; an assembler needs component relationships; an inspector needs criteria for deciding whether the result is acceptable. Match the information to the reader's job. For drawing-based work, use Creating Drawings from CAD Models to prepare the sheets and CAD History, Versions, and Sharing to distinguish an editable design from a preserved milestone.

Supporting detail: Addendum 31 — Does every design require a separate drawing?.

Follow the specified drawing standard and its applicable edition

Standards give drawing readers shared rules for interpreting views, lines, dimensions, and symbols. The ASME Y14 series is widely used in US engineering drawing practice; ISO technical drawing standards are widely used internationally. These are not exclusive geographic boundaries. Read the drawing's stated requirements rather than choosing a convention from a country name.

A convention is an accepted way of presenting information. A company may add conventions for sheet layout or numbering, but those choices must remain consistent with the governing requirements. Use the current applicable edition specified for the work; do not silently apply an old classroom example or change an existing drawing's governing edition.

Check units, projection method, and the stated standards before interpreting a drawing. Continue with Orthographic Projection and the Glass Box and Choosing Drawing Views for view interpretation. This overview does not reproduce standard clauses or serve as a compliance checklist.

Check the governing convention

Send the drawing type that answers the reader's job

Detail or part drawing

Defines an individual part for making and inspection, using the necessary views, dimensions, tolerances, material information, and notes. A part drawing is not the same thing as an enlarged detail view.

Assembly drawing

Shows how components relate and fit together. It may include item identification, assembly requirements, and overall or interface dimensions. See Exploded Views and Bills of Materials for exploded views, item balloons, and parts lists.

Working-drawing set

The coordinated drawings needed to make and assemble a product: typically assembly drawings and the required part drawings, with supporting lists and notes as needed. A set may span several sheets and drawing numbers.

An assembly view alone usually does not provide every requirement needed to manufacture each component. Confirm that the recipient has the required sheets and revisions.

Choose a drawing for making a part Choose a drawing for assembly

Read identity, units, and scale before reading dimensions

The title block identifies the drawing and records key information about it. Its layout varies. Read field labels; do not assume a familiar-looking border has familiar settings.

The part name tells you what the item is; the part or drawing number identifies the controlled record. Those numbers may be different. Units tell you how to interpret dimension values. Scale describes the displayed view size relative to the object, not the part's actual size. Check individual view labels for scale overrides, and use stated dimensions rather than measuring a print.

Find the units Interpret sheet scale

Find material, tolerances, and responsibility in the block or notes

General practice includes fields or notes for material, general tolerances, revision, and drawn/checked information. Some templates also carry dates, approval status, finish requirements, or a projection symbol. A material field may refer to a separate specification; read that reference rather than guessing from the appearance of the model.

A tolerance states the permitted variation from a requirement. Read the scope of the general tolerance note and any specific tolerances at features. Displaying more decimal places is not, by itself, a complete tolerance instruction. See Dimension Anatomy and Placement, Choosing Dimensions, and Hole and Feature Callouts.

Drawn and checked entries record responsibility. They do not replace the organization's approval or release process. Missing or conflicting requirements need clarification before the drawing is used.

Locate a material requirement

Choose the model and sheet settings before placing views

Start with the intended part or assembly and confirm its configuration or version: the selected design variant or saved design state. A drawing of the wrong variant can look convincing and still describe the wrong product. See CAD Files and Documents and CAD History, Versions, and Sharing.

A drawing template supplies starting settings. A sheet format supplies the border and title-block layout. CAD systems package these differently, so inspect the resulting sheet: size, units, projection method, scale, and dimension style all matter.

Use the workflow below as a sequence of tasks. Interface names vary by product and release; these are generic descriptions rather than menu instructions for SOLIDWORKS or Onshape.

Place a base view, then derive aligned projected views

Insert a base view from the model, choosing an orientation that communicates the shape clearly. Create projected views from that parent view, maintaining the required alignment and projection arrangement. Leave room for dimensions and notes.

The figure uses third-angle placement only as an example. Follow the drawing's declared projection method. Choose enough views to define the shape; three views are not a requirement for every part. Use Choosing Drawing Views, Section Views, and Auxiliary and Detail Views when ordinary views do not explain a feature clearly.

Choose how to add a related view

Distinguish dimensions that control geometry from dimensions that report it

A driving model dimension controls geometry, such as the length of an extrusion. A dimension created by selecting drawing geometry usually reports that geometry. Changing a displayed label is not a sound way to change the part.

Some CAD workflows import model dimensions into drawings and allow linked edits to affect the model. Check the dimension's type and behavior before editing. Do not assume that all drawing dimensions are editable model controls, or that all are independent annotations.

Select dimensions to communicate manufacturing and inspection requirements, not merely every value used while modeling. Add needed tolerances, material information, and feature notes; CAD does not infer all design requirements from shape. Use Choosing Dimensions and Dimension Anatomy and Placement for the dimensioning method.

Distinguish a dimension from a label

Choose a part, assembly, or drawing for the work you need to do

A part describes geometry. An assembly positions components relative to one another. A drawing communicates that design through views, dimensions, and notes. Start by deciding which job you need the document to do.

SOLIDWORKS part: .sldprt

Contains part geometry and its modeling features. A part can contain one body or multiple bodies; the file extension does not mean there is exactly one solid.

SOLIDWORKS assembly: .sldasm

References components, including parts and subassemblies, and stores their arrangement and assembly relationships.

SOLIDWORKS drawing: .slddrw

Usually references a part or assembly to generate drawing views. It is a separate document from the model.

Continue with Feature-based Modeling, Assembly Files and Mates, or Orthographic Projection and the Glass Box for the modeling and drawing methods.

An Onshape document holds tabs inside a workspace

An Onshape document is a container for related design information. Open a workspace to edit that information, then select the tab for the task.

• Part Studio: create geometry using sketches and features. One Part Studio can produce several related parts.
• Assembly: insert and position part or subassembly instances and define their relationships.
• Drawing: create drawing sheets and views of models.
• Tabs and tab folders: organize the document's contents. Use the Tab Manager to find a tab when the row becomes crowded. A tab folder organizes tabs; it does not mate parts together.

Several parts created together in a Part Studio are not automatically an assembly with motion relationships. See Sketch Entities and Planes to begin geometry and CAD History, Versions, and Sharing to distinguish a workspace from a version.

Supporting detail: Addendum 33 — Vendor help for the document model.

Keep referenced files together when you transfer a design

For a typical file-based SOLIDWORKS design, the assembly points to component files, and a drawing points to its model. Sending only the assembly file may leave the recipient without the parts. Renaming or moving files outside a reference-aware workflow can break those connections.

Use Pack and Go to gather a design's related files. Review the package contents, including required drawings, then open the transferred design and check for missing references. Files can be reorganized when references are updated; they do not have to remain permanently in the original folder.

Supporting detail: Addendum 35 — Why a folder copy needs checking.

Check file references Choose a tab Check units

Zoom, pan, and rotate change your view of the model

Zoom changes how large the model appears. Pan shifts it across the window. Rotate orbits the view so you can inspect another side. These viewing operations do not resize the part or move an assembly component.

Use zoom to fit to recover the whole model, zoom to window to enlarge a boxed region, and zoom to selection when you need a selected detail. Mouse buttons, modifier keys, and wheel direction depend on your device and control preferences. Check those settings instead of assuming two platforms use the same gestures.

Use Onshape's view cube or SOLIDWORKS view-orientation controls to return to a known direction. The axis triad helps you keep track of model directions while orbiting.

Normal to looks straight at a selected plane

Front, rear, top, bottom, left, and right are standard model directions. Normal to a planar face or sketch plane means looking along a direction perpendicular to it. An inclined face can therefore have a normal view that is different from every standard view.

Isometric, dimetric, and trimetric are angled parallel-projection views. The three principal axes have equal foreshortening in isometric, two equal in dimetric, and three different in trimetric. Perspective adds apparent size change with distance; turn it off when comparing parallel projected shapes.

Supporting detail: Addendum 37 — Viewing direction is separate from drawing layout.

Choose a display style for the edges you need to inspect

Keep the viewing direction fixed while comparing styles. Shading shows surfaces; edge settings decide which boundaries you can see. Labels differ between platforms, so read the option's effect.

Shaded without edges

Filled surfaces emphasize overall form without drawn edge outlines.

Shaded with edges

Filled surfaces plus visible edge outlines make face boundaries easier to follow.

Hidden lines/edges removed

An unshaded view shows visible edges and leaves concealed edges out.

Hidden lines/edges visible

Concealed edges are also shown, distinguished from visible edges. Useful for finding geometry behind the front surface.

Wireframe

Shows the edge framework through the model without opaque shaded faces. Overlapping edges can make depth difficult to read.

Onshape also provides translucent display and shaded display with hidden edges. Translucency lets you see through faces; hidden-edge display highlights concealed boundaries. Neither removes material.

Supporting detail: Addendum 38 — Find the view options in vendor help.

A model section view reveals the inside without cutting the part

Use a section view in the model window to clip away the near portion visually. Choose a plane or planar face, set the cut position and direction, and inspect the exposed interior. Turn the section off afterward to see the complete model again.

A viewing section does not create an extruded cut feature. It also does not automatically create a documented section view on a drawing sheet. See Onshape Section View help for the available section controls.

Mass needs material density as well as geometry

Assign a material to the intended part or body before relying on mass properties. A color or metallic appearance alone is not proof that the material density is correct. Check which bodies or components are included, the units, and any overrides before accepting mass or center of mass.

For a uniform solid, mass = density × volume. A correct volume with the wrong density still gives the wrong mass. Center of mass describes how mass is distributed; it need not lie inside the solid material of a hollow or curved part.

Supporting detail: Addendum 40 — Material assignment and mass-property help.

Choose a display style Check normal to Check a section Check mass Check a selection

The feature list describes how geometry is built

The SOLIDWORKS FeatureManager design tree and the Onshape feature list help you find sketches and modeling features. Later features can depend on earlier geometry. Rename important features so another reader can tell what they do.

A tree also contains items such as planes, bodies, or components; not every row is a modeling operation. To understand how features build a part, continue with Feature-based Modeling.

A rollback bar lets you work at an earlier position in the feature sequence while later features are temporarily left out of regeneration. Move it forward again to evaluate the complete model and check dependent features. Rolling back does not retrieve an old saved revision, and it is not the same operation as separately suppressing one feature.

Supporting detail: Addendum 41 — Rollback follows the regeneration sequence.

A SOLIDWORKS save or file copy needs its own revision plan

In a local file workflow, Save writes the current document to disk. A deliberate copy can preserve an earlier state, but a filename alone does not establish a managed revision or capture all referenced files. Keep descriptive names and know which copy is the active design.

Before copying an assembly or drawing for an alternative, check what its references will point to. Two assembly copies can still use the same part file; editing that shared part can affect both. Use the transfer checks in CAD Files and Documents.

SOLIDWORKS installations may use PDM or connected data management for version and revision control. Follow that system's workflow when present; local Save and Save As are not a universal replacement for it.

Choose the sketch plane before drawing the shape

A 2D sketch is a set of points and curves on one plane. The plane places the sketch in the model; the sketch's origin and axes give you references for locating its geometry.

• Standard plane: Front, Top, or Right is a useful starting reference for a new part. Choose the view that makes the intended profile easiest to describe.
• Model face: use an existing planar face when the new sketch belongs on that face. A curved face is not itself a 2D sketch plane.
• Reference plane: an added plane can locate a sketch where the standard planes and existing faces do not.

The origin is a point, not a plane. Starting a line or circle at the origin can anchor its position, but you still need a sketch plane. You may start elsewhere when that suits the design; then constrain the location relative to a deliberate reference.

Look normal to the sketch plane: straight at it, rather than at an angle. Horizontal and vertical refer to the sketch's axes, even when you rotate the model on screen.

Supporting detail: Addendum 43 — Sketch placement in Onshape.

Use the simplest entity that describes the shape

Rectangle and slot tools create useful groups of geometry. They do not guarantee that the resulting sketch is fully defined. Inspect their relations before adding more.

Supporting detail: Addendum 44 — Find the tools by their software names.

Construction geometry guides the sketch without outlining material

A centerline is a common use of construction geometry: a reference for a center, symmetry, angle, or axis. Construction geometry participates in dimensions and relations, but does not serve as the ordinary boundary of a filled profile.

In SOLIDWORKS, Centerline creates construction geometry. In Onshape, use Construction to toggle selected sketch entities or to create construction geometry. Use a construction circle for a layout circle just as you would use a construction line for an axis.

Supporting detail: Addendum 45 — Vendor reference for construction geometry.

Check connections before moving on to a feature

Two endpoints that look joined may still be separate. A tiny gap can prevent a profile from closing. Use a coincident relation to make the connection intentional, then inspect the sketch.

Closed and fully defined are different checks. A closed circle can still move or change size. A fully defined chain of lines can still be open. Later features such as extrude or revolve use sketches in different ways; choose the profile that the intended feature needs.

Continue with Geometric Relations in Sketches and Fully Defined Sketches and Design Intent. For view interpretation, see Orthographic Projection and the Glass Box; for drawing dimensions, see Dimension Anatomy and Placement.

Practice: choose a sketch reference

Relations preserve geometry when dimensions change

A geometric relation is a rule the sketch must continue to satisfy: two lines stay parallel, two circles keep one center, or an endpoint stays on a curve. Onshape generally calls these rules constraints; SOLIDWORKS calls them relations.

Choose the entities carefully. Selecting a circle's center is different from selecting its circumference. A relation can remove some motion while leaving other motion available. The diagrams show only the named rule, not a complete dimensioning scheme.

The before/after drawings are original geometry diagrams, not software icons. Their line colors do not indicate sketch status.

Coincident connects a point; midpoint puts it halfway along

Supporting detail: Addendum 46 — Point selection and vendor names.

Collinear shares a line; parallel shares only its direction

Software vocabulary: SOLIDWORKS has a Collinear relation. Onshape's documented toolbar has no separate Collinear entry. For two nonzero straight segments, placing both endpoints of one coincident with the other's underlying line enforces the same geometric condition. This is a construction from point-on-line constraints, not an Onshape command name.

Horizontal and vertical use the axes; perpendicular uses another line

Supporting detail: Addendum 47 — Why horizontal plus vertical can already supply a right angle.

Concentric shares a center; equal shares size; coradial shares both

Supporting detail: Addendum 48 — Check the circular relation definitions.

Tangent controls direction at contact; Fix holds a reference in place

SOLIDWORKS qualification: its relation reference says endpoints of a fixed line can still move along the underlying infinite line, and arc endpoints can move along the supporting circle. Check the entity and its endpoints. Onshape describes Fix as grounding the selected entity on the sketch plane.

Supporting detail: Addendum 49 — Vendor help for tangent and fixed geometry.

Watch automatic relations, then check what was stored

Sketching tools can add relations while you draw. A visual alignment is useful feedback; inspect the resulting relation icons before assuming the intended rule is present.

• SOLIDWORKS: with Automatic Relations enabled, its documented cursor cues include horizontal, vertical, coincident, midpoint, perpendicular, and tangent. Hold Ctrl while sketching to suppress automatic relations temporarily.
• Onshape: Automatic Inferencing documents horizontal, vertical, midpoint, parallel, and coincident as common inferences. Hover near existing geometry to activate the relevant inference; Shift suppresses inferencing while dragging.

These are documented examples, not an exhaustive promise for every tool. For equal, concentric, coradial, collinear, or fix, deliberately apply or verify the required rule. Rectangle, slot, and other creation tools can supply their own relations.

If an unwanted rule was stored, remove that specific rule before adding a conflicting dimension. Continue with Fully Defined Sketches and Design Intent.

Supporting detail: Addendum 50 — Automatic behavior depends on the tool and settings.

Practice: distinguish circular relations

Count independent ways the geometry can still change

A degree of freedom (DOF) is one independent variable still available to change. Constraints remove freedom. Count the geometry's possible motion, not the number of icons.

A circle's diameter dimension removes one DOF; its center can still move in two directions. Making its center coincident with the origin removes those two. A line with one endpoint at the origin still has length and direction to determine.

Supporting detail: Addendum 51 — Why subtracting one per relation gives wrong answers.

A driving dimension controls size; a driven dimension reports it

A driving dimension is a constraint: changing its value asks the solver to change the geometry while keeping the other rules. Length, angle, radius, diameter, and location dimensions can all supply constraints.

A driven or reference dimension measures a result already controlled elsewhere. It does not remove another DOF. For example, a circle whose size is set by a 24 mm driving diameter already has a 12 mm radius; a second driving radius dimension duplicates that control.

Use a relation for an enduring geometric rule and a dimension for the independent value you intend to change. Two lengths that must remain equal need an equal relation and one driving length, rather than two unrelated numbers that happen to match today.

Onshape automatically makes a newly added dimension driven if it would over-define the sketch. Check whether a displayed value is driving before expecting it to control geometry.

Supporting detail: Addendum 52 — Software treatment of redundant dimensions.

For drawing presentation and dimension placement, see Dimension Anatomy and Placement.

Read the sketch state in the software you are using

• Under-defined / underconstrained: some position, orientation, or size remains free.
• Fully defined / fully constrained: no free motion remains with the current driving values. Editing those values can still change the sketch.
• Over-defined / overconstrained: dimensions or relations conflict or add control the solver treats as redundant. Repair the conflicting set.

Read status messages and inspect relations as well as color. One black edge does not prove that the entire sketch is fully defined. An under-defined construction line or endpoint can be easy to overlook.

Supporting detail: Addendum 53 — Current vendor references for status colors.

Test design intent with a change, not just the starting shape

Fresh practice part: a circular inspection plate. Sketch two circular boundaries for an annular plate. Put their common center at the origin; use concentric and separate diameter dimensions of 46 mm and 18 mm. Increasing the outer diameter to 58 mm should leave the inner opening centered and unchanged in size.

Fresh practice part: a rectangular label blank. Use an axis-aligned rectangle with its lower-left corner at the origin, width 64 mm, and height 22 mm. Increasing the width to 80 mm should move the right edge while the left edge stays at the origin. If the intended part must grow equally left and right, choose a centered construction instead.

These two origin choices describe different editing behavior. There is no single best anchor for every part. Decide what should stay put before dimensioning.

Practice: count remaining freedom Practice: spot duplicate control

Repair the unwanted rule, then check the intended change again

When an added dimension causes an error, inspect what already controls that measurement. Keep the relation or dimension that expresses the intended design. Remove the duplicate, or make a measurement driven if it is only there to report a result.

A horizontal line cannot also have a nonzero vertical separation between its endpoints. Equal circles cannot have different driving diameters. These are contradictions; adding still more dimensions will not solve them.

SOLIDWORKS offers Display/Delete Relations and SketchXpert for diagnosis. Onshape's Constraint manager filters constraints and dimensions to help locate problems. A suggested deletion is still a design decision: check what behavior you would lose.

Supporting detail: Addendum 54 — Redundancy is not the same as contradiction.

Return to Geometric Relations in Sketches to compare rules, or Sketch Entities and Planes to review the geometry they act on.

Build the main shape, then add and remove material

A parametric model stores instructions for building a shape. Dimensions and relationships are inputs; the solid is the result. Change an input and rebuild to see the result update.

The base feature creates the initial solid. Later features add material, remove material, or modify faces and edges. For a simple spacer, start with its main cross-section and extrude it. For a stepped round knob, a revolved section may describe the main shape more directly. There is often more than one valid feature sequence.

A body is a connected piece of solid geometry. A SOLIDWORKS part file can contain multiple bodies. An Onshape Part Studio can create multiple parts from a shared feature list. Neither arrangement, by itself, defines assembly motion or assembly relationships.

Start with sketch dimensions and relations in the Engineering Graphics collection. Then choose extrude or revolve for a straight or rotational shape, or sweep or loft for a path or a changing cross-section.

The feature tree records a build sequence and its dependencies

Read the tree from the base feature toward the end. A feature that supplies a sketch, face, edge, or other reference is a parent; a feature that uses that reference is a child. A child can depend on more than one parent. Being later in the list does not, by itself, make a feature a direct child of every earlier feature.

For example: a plate extrusion supplies a top face for a hole-position sketch. A hole feature uses that sketch. A pattern uses that hole as its seed. Delete the hole and the pattern loses its seed; delete the plate and the sketch loses its support as well. Inspect the deletion dialog before accepting dependent deletions.

Rename features for their purpose, such as Main plate, Locating hole, and Hole row. Renaming a feature in the tree is different from renaming a referenced part file. File references need their own reference-aware workflow.

Supporting detail: Addendum 55 — Why a small edit can break a later feature.

Choose references that express what must stay aligned

A reference plane locates a sketch or defines symmetry. A reference axis supplies a direction or center of rotation. Neither adds material. Use the origin and default planes when they express the design; add offset, angled, or mid-planes when needed. Reference geometry can also have parents.

Design intent is what should stay true when dimensions change. A centered plate should grow equally on both sides of its center plane. A hole required to pass through the plate should remain through when the plate gets thicker. A row of identical holes should share one seed definition and a spacing rule.

Put major shape and functional references early. Add small edge treatments later when they are finishing details. This is a useful starting order, not a rule that every fillet must be last: a large blend that defines the main shape may belong before shelling or other features.

Supporting detail: Addendum 57 — Fewest features is not always the best model.

Extrude carries a cross-section in a straight direction

For a plain solid extrusion, select a closed sketch region and give it depth. A rectangular region makes a block; a circular region makes a cylinder. Without draft, the cross-section remains constant along the extrusion.

A boss/base extrusion creates or adds solid material. An extruded cut removes material where the extrusion intersects the target solid. Check the arrow, preview, and selected bodies. A cut pointing away from the part cannot remove material from it.

In Onshape, choose the result operation New, Add, or Remove. In SOLIDWORKS, check the boss/cut command and merge or feature scope settings. Adding touching material and creating a separate body are different intentions.

Supporting detail: Addendum 59 — Closed profiles, thin features, and surfaces.

Revolve rotates a section around an axis

Select a section, an axis of rotation, and an angle. A full turn is 360°; a smaller angle produces a partial rotational shape. A boss revolve adds material, and a revolved cut removes it. Start with a closed section on one side of the axis for a straightforward solid revolve.

A straight sketch line, centerline, or reference axis can define rotation when supported by the command. The axis must be deliberately located. A diameter describes the distance across a round shape; the distance from the axis to its outer wall is the radius.

A stepped sleeve can often be built with one revolved section including its bore. Repeated extrusions and cuts can also build it, but put the coaxial steps under separate controls. Choose the sequence that makes the important dimensions easiest to change.

Supporting detail: Addendum 61 — Check overlap and axis selection before adding complexity.

Pick the base feature from the shape's main organizing rule

Use extrusion when a useful section stays the same along a straight direction. Use revolution when a useful section repeats around an axis. A cylinder can be made either way. A rotationally stepped part often makes the reason for choosing revolve clearer than a plain cylinder does.

Before accepting either feature, confirm the profile, direction or axis, end condition or angle, and result body. Then make one trial dimension change. Does the model still express the intent described in Feature-based Modeling?

Practice choosing a base Practice a scoped feature count

A sweep needs a profile and a path

A profile describes the cross-section; a path describes where it travels. A circular profile swept around a smooth bend makes a bent solid rod. An annular profile can make a tube. For a basic sweep, keep the section size constant and choose how it stays oriented along the path.

Place the profile on a plane normal (perpendicular) to the path at its start for an easy first construction. Constrain its position to the path. A shape that looks connected in one view can still be separated in three dimensions. Select the complete intended path, not a neighboring model edge.

A sweep can create material or remove it from an existing part. Advanced sweep options can control twist or scaling; a constant circular section is a simpler starting case. See Onshape: Sweep.

A loft passes through profiles selected in order

A loft transitions between two or more sections. Put sketches on suitable planes, then select the sections in the order the shape should pass through them. A broad oval transitioning to a smaller oval is a simple example; the section size changes along the length.

Use a guide curve when the profiles alone do not control the shape between them. For a straightforward boundary guide, constrain it to meet every profile at the intended boundary point. A Pierce relation can locate a sketch point where a curve crosses that sketch plane. Do not accept a connection solely because it looks right in an isometric view.

Match corresponding locations around successive profiles. If one section's corner connects to an unrelated corner on the next, the loft can twist. Inspect connection handles and a section view before adding more profiles.

Supporting detail: Addendum 62 — More profiles do not automatically make a better surface.

Use the controlling geometry to choose sweep or loft

These are starting choices, not exclusive capabilities. For example, a loft can follow a centerline, and a sweep can vary with advanced controls. Prefer the feature that states the intended change clearly.

Practice profile and path Practice changing sections

Pattern a seed when the copies should change together

A seed is the original feature being repeated. A feature pattern makes the repetition explicit: edit the seed's size once and rebuild the copies. Model independent features when their sizes or locations must change independently.

A linear pattern uses a direction, spacing, and count. For a single-direction row with N total instances including the seed, the distance from first center to last is (N − 1) × spacing. Some dialogs also offer a total-span mode; check which distance the field means.

A circular pattern repeats around an axis. N evenly spaced instances around a complete circle have an angular pitch of 360°/N. A partial arc with both endpoints occupied instead has N − 1 intervals across that arc. Inspect whether the dialog asks for total angle or angle between instances.

Choose feature, face, or body/part pattern deliberately. A feature pattern repeats selected operations; a body/part pattern repeats a larger solid. Check target bodies, skipped instances, and whether every copy actually intersects the intended material.

Supporting detail: Addendum 63 — Copied geometry and recalculated end conditions can differ.

Practice linear spacing Practice angular spacing

Mirror across a plane when symmetry is the rule

A mirror reflects selected features or bodies across a plane. Corresponding points lie at equal distances on opposite sides. It is not a rotation: an asymmetric shape changes handedness.

A stable center plane is usually a better symmetry reference than a face likely to move independently. Check whether the mirror should join material into one body or create another. Assemblies use separate tools to position components; part-level mirror features do not define assembly motion.

See Onshape: Mirror for selection and result options.

Practice symmetry

Hole features store type and size as well as position

Use a hole feature when the hole needs structured information such as a fastener size, fit, counterbore, countersink, or tapped-hole specification. A counterbore is a larger cylindrical recess; a countersink is a conical recess. A plain circular cut can make geometry, but does not automatically carry the same hole definition.

In SOLIDWORKS Hole Wizard, use Type for the hole parameters and Positions for its centers. Select the appropriate standard, type, size, fit where offered, and end condition. Locate the centers with dimensions and relations. Different hole types require separate Hole Wizard features.

For tapped holes, distinguish drill depth from thread depth. A cosmetic thread represents thread information without cutting a helical groove in the solid. Inspect the selected thread option before expecting detailed thread geometry in an export.

Read hole callouts and drawing symbols in the Engineering Graphics dimensioning topics. This page covers the model feature, not callout syntax.

Supporting detail: Addendum 64 — Hole options depend on type and software version.

Fillet rounds an edge; chamfer bevels it

A fillet creates a rounded transition. A chamfer creates a beveled transition. Select the intended edges, set the radius or chamfer dimensions, and inspect the preview all the way around the selection. A small radius can still fail where neighboring faces leave too little room.

Keep edge treatments separate when they have different functions or are likely to change independently. Cosmetic edge breaks often belong late; a large blend that controls the main shape may belong early. See planning feature order.

Shell hollows a solid and leaves a controlled wall

Select faces to remove and specify the remaining wall thickness. Removing the top face of a block makes an open container; keeping all faces can make an enclosed cavity. Check whether the thickness is offset inward or outward.

If shell fails, inspect small radii and narrow regions where offset faces collide. Try a simpler outer shape or revisit the intended thickness. Do not silently reduce a required wall just to make the command succeed. See Onshape: Shell.

Practice hollowing a part

Draft tapers faces; a rib adds a thin support

Draft inclines faces relative to a pull direction, often to help a molded part release. In a neutral-plane construction, that reference keeps its size while selected side faces tilt. Check the direction and which end grows or shrinks. There is no universal draft angle for every material and process.

A rib adds a thin web between supporting regions. It usually starts from sketch curves plus a thickness and direction. Although grouped here with finishing features, a rib needs sketch geometry. Check that it meets the intended walls and merges with the intended part.

See Onshape: Draft, Rib, and the feature tool glossary. After any applied feature, rebuild, inspect the section, and make a trial change to its parent geometry.

Practice support features Practice draft

An assembly records which parts belong together and how they fit

A part defines a component's shape. An assembly places instances of parts and subassemblies and records relationships between them. Two instances of one part can occupy different positions while using the same part definition.

In a file-based SOLIDWORKS assembly, the .SLDASM normally references external .SLDPRT and other assembly files. An assembly drawing references the assembly. Sending only the assembly file can leave the recipient without its components. Virtual components are an exception: their definitions can be stored inside the assembly.

Onshape organizes Part Studios, Assemblies, and Drawings as tabs in documents. Inserted instances reference their source definitions; a tab name is not a Windows filename. Share the document with the appropriate access and identify the intended version when a fixed design state matters.

Supporting detail: Addendum 65 — Definitions, instances, and design changes.

Ground a base, then count the motion you intend to keep

A free rigid component in three-dimensional space has six degrees of freedom (DOF): translation along three axes and rotation about three axes. A degree of freedom is an independent motion, not a count of arrows or mates.

Choose a base or housing as the reference. Fix it, or fully locate it to the assembly origin and planes. In SOLIDWORKS, insertion options include fixing only the first component, fixing inserted components, or leaving them floating. Check the actual state; do not assume that the first component is always fixed. Fixing a base away from the origin holds it there; it does not move it to the origin.

A lever should still rotate about its pivot. A cover should stay put. Fully locating every moving part would turn a mechanism into a rigid model.

Supporting detail: Addendum 67 — Check the insertion setting.

Use geometric mates to describe the intended contact

Select the actual locating faces, axes, or reference planes. The same mate name can accept different geometry, so its effect depends on what you select. The diagrams below are schematic before/after comparisons, not complete constraints for whole assemblies.

Coincident

For two planar faces, put their supporting planes together. The faces can still slide in that plane and rotate about its normal. Coincident planes do not guarantee that finite faces overlap.

Concentric

Put two cylindrical axes on the same line. Without a rotation lock or other mates, a shaft can still slide along and rotate about that line.

Supporting detail: Addendum 68 — Why subtracting one DOF per mate gives the wrong answer.

Parallel and perpendicular mates set orientation

Parallel keeps selected planes parallel without setting their separation. Perpendicular keeps selected planes at a right angle. Neither condition alone fully locates the part. These diagrams show the planes edge-on.

Distance, angle, and tangent mates control gaps and contact

Distance sets a separation between selected entities. For parallel planar faces, use the normal gap, not a slanted edge length. Angle sets the angle between selected entities; check alignment and direction so the model uses the intended side of the angle.

Tangent keeps compatible curved and planar or curved surfaces touching tangentially. Tangency alone does not enforce rolling without slipping.

Choose a joint or mechanical relationship when motion is the point

For a simple lever on a grounded pin, align the pivot axes and locate the lever axially. Leave rotation free. A hinge mate expresses this single rotational freedom directly. In Onshape, a Revolute mate serves that joint purpose; Cylindrical allows axial slide and spin, Slider allows one translation, and Fastened allows no relative motion. Mate connectors establish the joint frames.

A slot mate locates a pin or similar feature relative to a slot. Select free travel or a prescribed position to match the design; other motions depend on the selections and remaining mates. Onshape's Pin Slot mate allows rotation about the connector's Z axis and translation along its X axis. Set appropriate travel limits; it is not an identical set of SOLIDWORKS slot options.

A gear mate or gear relation couples rotations by a ratio. Locate the shafts first. The relation does not create teeth or prove they mesh without interference. Use Gear Ratios for the ratio calculation and Torque for the separate question of turning effort.

Supporting detail: Addendum 69 — Compare vendor joint vocabulary.

Build reusable parts and subassemblies with deliberate dependencies

Bottom-up design starts with existing parts and brings them into an assembly. Top-down design starts with an overall layout or shared design references and develops parts around them. A mixed approach is common: use a shared layout for custom plates and insert purchased hardware.

A subassembly groups parts into a reusable unit. Give it a useful function, such as a pivot cartridge, rather than hiding unrelated parts in it. Check whether its internal joints are allowed to move at the parent level; a rigid subassembly can make a working joint appear locked.

Top-down references can keep mating holes aligned when the layout changes, but they also create dependencies. Keep the direction of those dependencies understandable and check them when copying or sharing the design.

Supporting detail: Addendum 70 — What makes a feature top-down?.

Use SOLIDWORKS Toolbox or Onshape Standard Content, where available, for standard hardware. Choose the standard, size, thread pitch, length, and material or grade deliberately. A visually similar bolt or an automatic size suggestion is not a completed fastener selection.

Supporting detail: Addendum 71 — Library hardware still needs checking.

For sketching and part-modeling topics, browse Engineering Graphics and CAD. Continue with Checking CAD Assemblies and Exploded Views and Bills of Materials.

Practice shaft freedom Choose locating mates

Judge remaining motion against the design intent

A successful rebuild means the CAD system can solve the model. It does not mean the model describes the mechanism you intended. Try moving each component and name the motion that should remain.

Under-mated means freedom remains. That is a defect for a loose cover, but rotation at a lever pivot can be intentional. Over-mated or conflicting constraints ask for relationships that the solver cannot satisfy together. A redundant constraint repeats an existing condition; it adds no useful location and can complicate diagnosis.

For a shaft with concentric axes and seated shoulder faces, one rotation remains. Adding another mate that merely keeps those axes parallel is redundant. Adding an angle mate to lock that remaining rotation may be correct for a stationary shaft and wrong for a rotating lever. Review Assembly Files and Mates for the geometry.

Check interference and clearance as different questions

Interference is shared volume: two solid parts occupy the same space. Clearance is the gap between parts. A model with no overlap may still lack enough room for movement, manufacturing variation, or tool access.

Run interference detection on the relevant components in the intended configuration and position. Inspect each result. An intentional press fit or simplified thread representation can produce overlap, but an unwanted bolt tip inside a moving path needs attention. Record the reason for any accepted interference.

Supporting detail: Addendum 72 — Selection scope can hide an interference.

An exploded view separates parts to explain their relationship

An assembled view shows the working arrangement. An exploded view spaces components apart so the reader can identify them and follow how they fit. The separation is for communication; it is not an operating clearance or a change to the part geometry.

Separate components along understandable directions, keep related parts aligned, and use explode lines where the connection would otherwise be unclear. Preserve the working assembly and create a saved exploded view rather than deleting mates to pull the model apart.

Supporting detail: Addendum 74 — Use the saved view in a drawing.

A balloon finds a BOM row; a part number identifies the component

A bill of materials (BOM) lists the components required for the stated assembly. A drawing balloon points to a component and usually shows its BOM item number. The item number is a row identifier in that drawing's list. The part number identifies the part for reuse, manufacture, or purchase.

Balloon 4 identifies HW-410, not four washers. Its quantity is two per assembly. This list has five distinct rows and six component instances. Repeated instances of the same specified part share an item number; different sizes or variants need distinguishable identities.

Supporting detail: Addendum 75 — Linked tables reduce manual mismatches.

Decide whether the BOM lists units or their internal parts

A top-level list can show a purchased subassembly as one unit. A structured list can show the assembly hierarchy, while a flattened list collects the underlying components without that hierarchy. State the scope before interpreting a quantity. Do not order a complete unit and all its contents accidentally.

Verify part numbers, descriptions, quantities, and relevant configuration or revision information. A library model's filename is not automatically a useful purchasing description. The teaching identifiers above are examples, not an orderable hardware specification.

Supporting detail: Addendum 76 — Subassembly display changes what the table means.

Use a certification to document assessed skills, not to replace design experience

A CAD certification is a provider's record that you passed a defined assessment. Depending on the program, that assessment may cover drawing interpretation, sketches, parts, assemblies, documentation, collaboration, manufacturing, or analysis. It can give a learner a concrete practice goal and give an employer one more piece of evidence about a specific product or workflow.

Its meaning is bounded. A credential does not guarantee employment, prove that every model is manufacturable, or replace a portfolio, coursework, supervised practice, and engineering judgment. Product names and versions also matter: proficiency in one CAD system does not automatically transfer to every other system.

This overview leads with mechanical CAD. Architecture and construction, CAM, simulation, additive manufacturing, product-data management, and platform roles are useful branches when they match the work you want to do. Program information below was checked against official sources on October 29, 2026; recheck the linked catalog before registering.

Choose the product and work first, then the credential level

Do not begin by looking for a universal Associate → Professional → Expert ladder. Providers use those words differently, and some products offer only selected levels. Begin with the software and tasks used in your course, internship, workplace, or intended field.

Core mechanical design

Look for sketching, parametric part modeling, assemblies, drawings, dimensions, materials, and model checks.

Specialized design

Sheet metal, surfacing, weldments, mold tools, drawing tools, and generative design usually require narrower practice than a general design credential.

Manufacturing and additive

CAM, turning, milling, additive-process, and design-for-manufacturing credentials connect geometry to process planning. They are not substitutes for machine or shop authorization.

Simulation

Static, thermal, flow, frequency, nonlinear, and other analysis credentials assess both software operation and interpretation. Passing does not make an unchecked result physically valid.

Platform and data roles

Cloud collaboration, revisions, lifecycle, PDM, and administrator credentials may assess data workflows rather than only geometry creation.

Read the assessed skills on the exact credential page. A badge for completing a course, a training certificate, and a certification earned by passing an assessment are not automatically the same thing.

Compare SOLIDWORKS and Autodesk mechanical paths

SOLIDWORKS

The official SOLIDWORKS catalog groups the general design path as Design Associate, Design Professional, and Design Expert, but the levels assess different depth rather than the same checklist three times.

Design Associate (CSWA)

Foundational sketches, common part features, patterns, dimensions, materials and mass properties, component insertion and mates, drawing views, and annotations.

Design Professional (CSWP)

Professional parametric part design from drawings, linked dimensions and equations, configurations and design tables, mass-property changes, and assembly modeling across three segments.

Design Expert (CSWE)

Advanced part and assembly problem solving, including multibody/imported geometry, complex features, in-context work, configurations, and advanced bills of materials. Eligibility requires CSWP plus at least four of exactly these five advanced-topic exams: Sheet Metal, Weldments, Surfacing, Mold Tools/Mold Making, and Drawing Tools.

Those five design specialties form the CSWE prerequisite set. Other Professional credentials—such as CAM, MBD, API, and Flow Simulation—assess valuable but different work and are not listed as substitutes in the CSWE requirement. Additive Manufacturing Associate assesses processes, materials, design, slicing, and preparation without requiring SOLIDWORKS software during the assessment.

The simulation family is separate: Simulation Associate covers statics, materials, loads, mesh, and result checks; Simulation Professional adds static, frequency, thermal, beam/shell, and convergence work; Simulation Expert requires CSWP, CSWA-S, and CSWP-S and adds advanced contact, composites, thermal, dynamics, and nonlinear analysis. Flow Simulation Professional is another specialty, not a step in that three-credential prerequisite chain.

Cloud xDesign and xShape credentials are not alternate names for desktop CSWA/CSWP. The xDesign Professional and xShape Professional pages require the relevant app, prescribed training, 3DSwymer Associate, ENOVIA Collaborative Industry Innovator Associate, and a new collaboration space. Exact student-cloud bundle mapping remains unclear, so confirm access before choosing one.

Route matters for students. Through the Academic Certification program, free exams depend on the school being an Academic Certification Provider, an active subscription, and region-specific license minimums; this is not an entitlement for every student. The current Design Premium for Students offer separately lists CSWA and CSWP attempts, while free Design Standard software does not list them. Recheck the current offer before purchase. Ordinary CSWP publishes no general prior-certification requirement, except that K–12 students using an Academic Certification Provider must first pass CSWA. The distinct CSWP-Academic route requires CSWA-Academic at least 30 days earlier and qualified, proctored institutional delivery.

Autodesk

Autodesk names four broad levels: Certified User (ACU), Certified Associate (ACA), Certified Professional (ACP), and Certified Expert (ACE). Not every product has every level, and the official overview does not establish a universal prerequisite ladder.

Mechanical starting points include ACU exams for AutoCAD, Inventor, and Fusion; ACA in CAD for Mechanical Design; ACP in Inventor for Mechanical Design, AutoCAD for Design and Drafting, and Design for Manufacturing; and ACE in Generative Design for Manufacturing. Optional extensions include Fusion CAM credentials, ACP in Simulation for Static Stress Analysis, and AEC credentials for Revit, Civil 3D, and BIM management.

ACU registration runs through Certiport; Autodesk's current ACU guidance says exams may be delivered online or in person, so do not assume a testing-center-only route. ACA, ACP, and ACE pages instead route candidates through Autodesk's application/dashboard to Pearson VUE or OnVUE. Those ACA/ACP/ACE exams use selected-response questions rather than live CAD software, so preparation should include concepts and workflow decisions as well as software practice. See Autodesk certification support for current policies and preparation routes. Free Autodesk education software and free learning resources do not establish a free exam or student discount.

Compare Onshape, Creo, NX, and Solid Edge

Onshape

The live Learning Center certification catalog lists Certified Onshape Associate for parts, multipart design, assemblies, drawings, and collaboration, and Certified Onshape Professional for advanced modeling, motion, in-context work, versioning, branching, and linked-data collaboration. No Associate prerequisite is published for Professional. Register through the Learning Center and its Training Dashboard. A student Associate voucher has been described only through a conditional preparation route; current course access and voucher availability must be confirmed.

PTC Creo

The current PTC Learning Connector uses Product Proficiency for foundational sketches, features, assemblies, properties, and analysis; Modeling Specialist for advanced design intent, sketches, and solids; and Surfacing, Sheetmetal, Assembly, and Documentation specialists for their named workflows. Older User/Associate/Professional labels should not replace the live catalog. Enroll through the specific Learning Connector exam with appropriate active LEARN access; learning paths are recommended, and the current FAQ says prior certifications are not prerequisites. A separate academic certification-only route offers Product Proficiency, Modeling Specialist, Assembly Specialist, and Documentation Specialist after Proxi.id academic verification. It does not include every specialist or prove a universal student entitlement.

Siemens NX

The live Siemens Xcelerator Academy catalog lists NX Design Associate for solid and assembly models, modeling strategies, parametric/non-parametric methods, and interpart links; NX Design Professional adds curves and surfaces, PMI, validation, downstream model use, and drafting. The NX Design learning map makes Associate a prerequisite for Professional. Register from the catalog's Buy route. Optional NX CAM Associate/Professional and Additive Manufacturing Associate paths assess manufacturing work. Academic discounts or free vouchers may depend on institutional licensing; no universal student entitlement is established.

Siemens Solid Edge

The Solid Edge registry publishes Associate, Professional, and Expert. Associate covers introductory parts, assemblies, sketches, and drawings; Professional adds advanced synchronous, sheet-metal, assembly, and documentation work. Associate before Professional is recommended, not stated as mandatory; Expert requires Professional and assesses advanced ordered/synchronous modeling and detailing. Use Getting Started to register, complete the profile, review the guide, and select an exam. Enrollment pages currently display the exams as free, but verify region and delivered software version.

Keep CATIA V5 and 3DEXPERIENCE credentials separate

Dassault Systèmes publishes two different families. 3DEXPERIENCE role certifications include Associate roles such as Mechanical Designer, Mechanical & Shape Designer, SheetMetal Designer, and Function Driven Generative Designer. Associate exams use the Edu Space and certification-credit route with access to the appropriate roles/apps. The Professional registry covers advanced Mechanical Designer, Function Driven Generative Designer, and SheetMetal Designer work through authorized certification centers—public centers for general candidates or private academic centers for their students. Role trigrams identify software roles, not separate marketed exam codes.

CATIA V5 certification is another center-delivered family, marketed at Associate and Expert levels for Part Design, Assembly Design, and Surface Design. Its catalog describes training and regular practice as preparation, but the inspected pages do not publish a prior Associate credential as a universal Expert gate. Contact an authorized center for the available V5 route rather than registering through the 3DEXPERIENCE Associate Edu Space.

Student CATIA/3DEXPERIENCE offers can bundle software and exams under eligibility, billing-country, age, and noncommercial-use conditions. Official pages conflict on the exact bundled exam roster and renewal wording, so confirm the cart and current student terms rather than promising a particular set of credentials.

Use one verified route from comparison through preparation

1. Name the product and work you want to demonstrate: general mechanical design, drawings, manufacturing, simulation, or data workflow.
2. Open the provider's current catalog and the exact credential page. Record the title, assessed skills, delivery route, and published prerequisites.
3. Mark recommendations separately from requirements. Confirm that you can access the needed software, account, testing center, or remote-proctor setup.
4. Ask your institution about participation or vouchers without assuming it has them. Verify any student offer, region, expiration, and checkout total directly.
5. Use official preparation materials without copying exam questions, answer keys, or protected sample parts. Practise the underlying workflow with original drawings and models.

For a worked preparation case, continue to CAD Certification Preparation. It uses CSWA to organize drawing, modeling, assembly, units, material, mass-property, checking, and revision practice while keeping the official exam specification outside CourseWiki.

Use certification as a goal for building dependable CAD skills

A CAD certification gives you a way to demonstrate skills assessed by its provider. Preparing for one can help you become more productive, build models that survive changes, and describe your skills on a resume. Passing does not guarantee a job or prove that every design you make will work.

The Certified SOLIDWORKS Associate (CSWA) is the worked case here, offered through Dassault Systèmes' SOLIDWORKS certification program. Its hands-on modeling workflow does not describe every vendor exam: some routes use selected-response questions, testing-center delivery, platform roles, or different software-access rules. Compare those routes first in CAD Certifications. CourseWiki is an independent learning resource and is not affiliated with or endorsed by Dassault Systèmes.

Practise reading, modeling, assembling, and checking

Use these general skill areas to organize practice; use the official description to confirm what your chosen certification assesses.

• Read a drawing: identify views, dimensions, and feature notes before building. Start with Drawing Terminology Review.
• Sketch deliberately: use dimensions and geometric relations to control size and shape. Review Geometric Relations in Sketches.
• Build and revise parts: choose features that express the shape, then change a dimension and check the result. Review Feature-based Modeling.
• Assemble components: place parts and constrain their intended positions or motion with mates. Review Assembly Files and Mates.
• Inspect the result: measure dimensions, check mass properties, and confirm the correct model state. Review CAD Model Views and Checks.

Build accuracy first, then practise with a time limit

Choose an original, ungraded drawing you have permission to use. Build the part without following a click-by-click demonstration. Explain how each view supports the geometry, then check the dimensions and material. Repeat with a changed dimension to see whether the model updates as intended.

Once that process is reliable, set a practice time limit. Include time to read, model, check, and save. Record where you lose time and practise that skill next. During an actual attempt, follow the provider's rules about navigation, returning to questions, and saving work.

Keep a short error log: drawing interpretation, sketch control, feature choice, assembly position, units, or material. Rebuild after correcting the cause instead of memorizing the previous answer.

Identify the view before interpreting the shape

This short vocabulary review supports CAD certification preparation. It is general drawing language, not a list of guaranteed exam terms.

A view is a picture of the part from a chosen direction. First identify how the picture represents the part; then read its lines, dimensions, and notes.

Orthographic view

The principal orthographic views look straight at the part from the front, above, or a side, using parallel lines of sight perpendicular to each viewing plane. Front shows width and height; top shows width and depth; a side view shows depth and height. Read the views together to understand one three-dimensional part.

Isometric view

An angled pictorial that helps you see width, height, and depth together. Its three principal axis directions are 120° apart and use the same scale. An isometric projection foreshortens lengths equally along all three axes; an ordinary isometric drawing lays out axis-parallel lengths at the chosen drawing scale. Use stated dimensions to model the part rather than measuring its apparent lengths on the picture.

Line conventions describe edges and centers within a view

A view type tells you how the part is represented. A line convention tells you what a particular mark means within that view. Visible, hidden, and center lines are line conventions, not additional view types.

Visible line

A continuous line shows an edge or outline you can see from this viewing direction.

Hidden line

Short dashes show an edge concealed by material.

Center line

A long-short pattern identifies an axis, center, or symmetry reference. It is not a physical seam in the part.

Read dimensions and callouts as instructions about features

Dimension and extension lines

A dimension gives a size or location. A dimension line is a thin line, usually ending in arrowheads, that shows the extent of the measurement; extension lines carry the edges of the measured feature out to it. Read the value and units instead of measuring a picture. See Dimension Anatomy and Placement.

Diameter and radius

Diameter spans a circle through its center; radius runs from its center to its edge. The diameter symbol is Ø; R denotes radius. Confusing them changes the modeled size. See how holes and arcs are called out in Hole and Feature Callouts.

Hole and feature callout

A note describing a feature, possibly including quantity, size, depth, or thread information. A through hole passes through the material; a blind hole stops within it. See Hole and Feature Callouts.

Tolerance

The permitted variation in a specified dimension. Read the stated limits or applicable drawing note; do not assume that every dimension has the same tolerance. See Dimension Anatomy and Placement.

Practise radius and diameter

Distinguish a section, a detail, and an auxiliary view

• Section view: shows the part as if cut by an imaginary plane so internal features can be read. A cutting-plane indication locates the cut; section lining identifies material crossed by it. See Section Views.
• Detail view: enlarges a selected area so small features are easier to read. Check its scale and labels.
• Auxiliary view: looks perpendicular to an inclined surface to show its true shape. Compare it with a detail view in Auxiliary and Detail Views.

Before modeling, point to the view or callout that establishes each feature. If a shape is unclear, look for another view rather than guessing from a pictorial.

Check the purpose of a detail view

Classify the mechanism before comparing process names

Additive manufacturing builds three-dimensional geometry by adding material. The standard process families describe how material is placed and joined. They are different from this course's five purpose categories, which describe what an operation is intended to accomplish.

Use three questions when you meet an unfamiliar name: What feedstock enters? What places or selects each region? What joins or solidifies it? Then ask what must happen after the build before the part is ready to inspect or use.

For the course's purpose model, additive shape-building is primarily Forming. Removing supports is a later Separating operation; curing or heat treatment can be Conditioning; finishing can change a surface. The seven AM families below do not replace those five purpose categories.

Supporting detail: Addendum 78 — Vocabulary, brand attribution and source scope.

Seven families place and join material in different ways

Material names do not move freely between families. A printer, process version and qualified feedstock must be considered together. Polymer, metal, ceramic, composite, sand and cementitious examples exist in particular systems; that does not mean every material works in every printer.

Powder and droplets can play three different roles

Powder bed fusion

The powder is the build material; selected regions are thermally fused during the build.

Binder jetting

The powder is the build material; jetted binder holds a green shape that may require later densification.

Material jetting

The droplets themselves contain build material; a separate support material may also be deposited in some systems.

HP Multi Jet Fusion belongs with powder bed fusion because agents help control where powder is fused by heat. It is not binder jetting simply because a printhead deposits an agent. See the manufacturer's mechanism comparison for that distinction.

Powder bed fusion repeats a spread, select, and lower cycle

Powder bed fusion (PBF) is one additive-manufacturing family. A machine spreads a thin powder layer, applies thermal energy to selected regions, lowers or advances the build, and repeats. Unselected powder remains around the growing parts until they are unpacked.

The family name does not specify one material or energy source. Polymer and metal examples can share the layer cycle while differing in temperature, atmosphere, thermal behavior, support strategy, cooldown, powder recovery, postprocessing and inspection.

Start with Additive Manufacturing Process Families for the seven-family map. PBF thermally fuses powder during the build; it is not binder jetting, where deposited binder first creates a green shape.

Supporting detail: Addendum 79 — Readable process sources.

Polymer SLS and MJF select powder in different ways

Selective laser sintering (SLS)

A laser scans selected regions of a polymer powder layer and thermally joins the particles. Unfused powder surrounds the parts in the stated process, so dedicated support structures are generally unnecessary; the build must cool before unpacking and depowdering.

Multi Jet Fusion (MJF)

A printhead places fusing and detailing agents on polymer powder, then applied heat fuses selected regions. The agents control fusion; they are not binder that leaves a green part for later sintering.

Both examples belong to PBF because powder is thermally fused during the build. Neither description proves that any polymer powder, color, wall, gap or enclosed cavity will work on a particular machine.

Loose powder can carry surrounding geometry during these stated polymer builds, but it must still be removed. A sealed hollow region can trap powder. An internal passage needs an accessible route for cleaning and inspection; “no dedicated supports” does not mean “no design constraints.”

Metal laser and electron-beam PBF need process-specific thermal reasoning

The metal examples here use a laser or electron beam to melt or fuse selected regions of metal powder. The part develops through repeated melt-and-solidify events, so orientation and connection to the build system can affect heat flow, residual stress, distortion and later removal.

In a stated laser PBF case, sacrificial supports may anchor an overhang to the build plate and conduct heat away. Loose metal powder surrounding the part is not automatically an adequate thermal path. That does not create a universal rule that every metal PBF system and geometry needs the same supports.

Electron-beam PBF has process-specific strategies and exceptions. Current commercial examples can reduce or replace traditional supports for some parts. Record the exact machine, material, melt strategy, orientation and acceptance plan instead of transferring one support rule to every metal powder process.

Supporting detail: Addendum 80 — Why the support statement is qualified.

Build the part by adding layers

Additive manufacturing makes a shape by adding material. This page uses thermoplastic-filament material extrusion: a printer feeds filament through a heated nozzle and deposits it along paths, much like a controlled hot-glue gun. Fused filament fabrication (FFF) is generic usage for this route; fused deposition modeling (FDM) is a registered trademark of Stratasys.

A slicer divides the model into horizontal cross sections and plans the paths for each layer. The nozzle and build surface move relative to one another to build the next layer. A CAD model describes the desired shape; the sliced file describes how a particular printer will make it.

This page focuses on filament printing. Resin, powder and metal routes use different placement, joining and post-build mechanisms; compare them in Additive Manufacturing Process Families. Their preparation, handling and finishing procedures are not interchangeable.

Use walls for the shell, infill for the interior, and supports where needed

Walls, also called perimeters, trace the outside and hole boundaries. Infill fills some of the interior. Solid top and bottom layers close the part. Increasing infill is not a substitute for choosing suitable walls and orientation.

Layer height sets the thickness of each deposited layer. Smaller layers can reduce the steps on sloped surfaces but usually add print time. They do not by themselves make a thin wall or tiny hole printable: nozzle size and extrusion width matter too.

Supports are temporary material beneath regions that cannot print reliably in the chosen orientation. They use material and time, may leave rough contact surfaces, and must be reachable for removal. A short bridge between two supported edges differs from an unsupported overhang; check the machine's demonstrated capability instead of assuming one universal angle limit.

Supporting detail: Addendum 82 — Why more infill does not solve every strength problem.

Orient for load direction, surface quality, and support removal

Ask which way the part will be pulled or bent. Filament prints are often weaker when a load pulls adjacent layers apart. For a straight bar pulled along its length, laying its length in the build plane is usually a better starting point than printing it upright. Test a representative part before relying on it under load.

Then consider the important faces. A face against the bed takes the bed's texture; a supported underside may need cleanup; a slope shows layer steps. Rotating the part can improve one surface while making another worse. A broad, stable bed contact usually makes the start easier than a narrow footprint.

Practice choosing an orientation

Use the preview and the failed part to find the next check

Missing thin feature

Inspect the sliced paths. A feature visible in CAD may be too thin for the selected extrusion width; revise the feature or an approved setup.

Loose first layer or lifted corners

Check bed preparation, first-layer setup, and the material profile against the machine procedure. Warping involves shrinkage as the part cools.

Sagging underside

Check the orientation, unsupported spans, and support placement before repeating the same job.

Gaps, strings, or shifted layers

Check material condition, extrusion, temperature/profile, and machine motion as appropriate. These symptoms have several possible causes; change one justified factor at a time and record the result.

In the preview, inspect the first layer, small holes, supports, and the final top layers. Estimate time and material before starting. Follow Equipment Operating Procedure and Machine Hazards and Housekeeping for operation and handling; the nozzle and build surface may remain hot after motion stops.

For parts that must fit together, continue to Choosing a Fabrication Process and Tolerances and Fits.

Use vector paths for outlines and raster scans for filled marks

A vector operation follows lines and curves. A raster operation scans across an area to make a surface image or filled mark.

A vector path can cut through a sheet or make a shallow score, depending on the material and settings. Raster engraving typically changes the surface without cutting out the part. A bitmap picture of an outline is not automatically a usable vector cutting path.

Practice choosing cut or engrave

Offset the path toward the waste by half the kerf

Kerf is the width of material removed by a cut. In the simple model below, the laser follows the center of a constant-width kerf. Half the removed width lies on each side of the path.

For an outside part boundary, move the path outward by kerf / 2. For an opening, move the path inward toward the material being removed. Without compensation, a cutout part becomes smaller and a hole becomes larger.

For a desired outside width W, the path-to-path width is W + k, where k is kerf. For a desired opening width H, it is H − k. These are whole-width changes; the offset at each edge is only k / 2.

Measure a test cut in the same material and setup. Kerf can vary with thickness, focus, and settings, and cut edges may taper. If software already compensates the path, do not apply the same allowance again. See Tolerances and Fits for fit requirements.

Practice an outside dimension Practice an opening

Treat power, speed, and pulse settings as a matched setup

Power controls laser output; speed controls how quickly the spot travels. With other conditions held fixed, higher power or slower travel generally puts more energy into a length of cut. That can also increase scorching or melting rather than improve the edge.

Frequency or pulse settings control how pulses are delivered. Controls may use pulses per second, pulses per distance, or a machine-specific scale; read the manual's definition. A percentage from one machine is not a transferable recipe for another.

Use the posted procedure and the manufacturer's starting settings for the exact machine, material, and thickness. Confirm the result on an approved test piece. Check that the cut separates and that engraving is readable before running the complete job.

Supporting detail: Addendum 85 — Manufacturer guidance for selecting a starting setup.

Confirm the material and stay with the operating laser

Only process materials approved for that machine. Suitable grades of wood and acrylic are common CO₂-laser examples, but coatings, adhesives, thickness, and machine capability matter. A material that can be marked is not necessarily one the machine can cut through.

Do not cut or engrave PVC or vinyl containing PVC. Do not guess the identity of an unknown plastic. Never leave an operating laser unattended. Use the required extraction and follow the machine procedure for a flare-up or other abnormal condition.

Use Equipment Operating Procedure, Fire Safety, and Personal Protective Equipment for the shared safety rules.

Supporting detail: Addendum 86 — Manufacturer safety reference.

Choose from the required shape and material first

Start with what the part must do. A process is useful only if it can produce the geometry in a suitable material with the required performance.

Filament printing

Builds three-dimensional shapes in layers. It suits changing cross sections, bosses, and internal features when those features can be printed and supports can be removed. Layer direction and service temperature affect the choice.

Laser-cut sheet

Produces planar profiles from a sheet of existing thickness. It suits flat panels, plates, and repeated outlines. Three-dimensional structures need joints, stacked layers, or another forming operation.

A flat nameplate with surface lettering is a natural laser candidate if the sheet is approved. A one-piece curved knob with a raised boss is a natural printing candidate if a suitable printable material meets the load and temperature requirements. Neither choice establishes production time without a job estimate.

For setup details, use 3D Printing from CAD and Laser Cutting and Engraving from CAD.

Design features the selected process can actually make

Printed walls and holes

Check that the slicer generates the intended paths. Leave access for support removal. Do not assume a CAD hole prints at its nominal size; measure a representative sample.

Laser-cut webs and corners

Leave enough material between cuts for the part to survive fabrication and use. Account for kerf and heat effects. An infinitely sharp CAD corner does not guarantee an infinitely sharp cut corner.

Sheet joints

Design slots from measured sheet thickness and the intended clearance. Kerf compensation controls the cut edge; clearance controls how two finished parts fit. They solve different problems.

Assembly

Plan how pieces enter their final position and how they are held. A collision-free CAD assembly does not prove that real parts will fit or can be assembled; see Assembly Files and Mates.

Supporting detail: Addendum 87 — Why there is no universal minimum wall or perfect press-fit allowance.