How to Use Interference Detection in SOLIDWORKS

Interference Detection is the SOLIDWORKS assembly check you run when two or more components occupy the same physical space. It is especially useful before releasing a design for machining, 3D printing, fabrication, or purchasing, because a small hidden clash can turn into a failed fit later.

Use this tool after the main assembly mates are in place, after a major design change, and again before you export drawings or manufacturing files. The check is quick on small assemblies, and on larger assemblies you can narrow the selected components so SOLIDWORKS only tests the area you are working on.

Open the Interference Detection tool

1. Open the assembly you want to check.
2. Go to the Evaluate tab in the CommandManager.
3. Click Interference Detection. You can also use Tools > Evaluate > Interference Detection from the menu.
4. Choose the components to include. If nothing is selected, SOLIDWORKS can check the full assembly.
5. Click Calculate to generate the interference list.

For a small assembly, checking everything is usually fine. For a heavy assembly, select only the fastener group, moving subassembly, enclosure, or bracket area you need to inspect. This keeps the calculation easier to read and usually much faster.

Read the interference results

After the calculation finishes, SOLIDWORKS lists each detected interference. Selecting an item highlights the problem area in the graphics window so you can see which parts overlap. The result may include the component names and the approximate interference volume, depending on the model and mode.

Do not fix every result automatically. Some intersections are real design errors, while others are intentional or harmless for your specific model. For example, a press fit, a simplified weld bead, or simplified thread geometry may appear as an interference even when the physical design is acceptable. The important step is to inspect each result and decide whether it should be corrected, ignored, or documented.

Fix common interference problems

Most real interferences come from one of four causes: an incorrect mate, a part revision that changed size, a fastener that is too long, or a clearance that was never modeled. Start with the simplest explanation before editing part geometry.

• Wrong mate: suppress or edit the mate, rebuild, and run the check again.
• Fastener clash: compare screw length, washer stack, and hole depth. If needed, update the hardware from Toolbox or your parts library.
• Missing clearance: edit the affected part and add the needed cut, slot, counterbore, or relief.
• Revision mismatch: confirm that the inserted component is the correct configuration and latest revision.

If the issue is around hardware, it may help to review how to use Smart Fasteners in SOLIDWORKS and how to use SOLIDWORKS Toolbox. Those workflows can reduce repeated fastener mistakes, but you should still run Interference Detection after changing hardware.

Use Ignore carefully

The Ignore option is useful when a listed interference is intentional. Use it for known conditions, not as a way to hide results you have not reviewed. If the assembly is part of a team workflow, add a note in the design documentation or drawing package so the next person understands why the overlap was accepted.

A good habit is to run the tool twice: once before you make corrections and once after the corrections are complete. New interferences can appear after moving a component or editing a part in context.

Interference Detection tips for larger assemblies

Large assemblies need a little more discipline. Instead of calculating the whole model every time, isolate the area being changed. Check one subassembly against another, test hardware groups separately, and suppress cosmetic or nonessential detail when it makes the results noisy.

If performance is still slow, open the assembly in a lighter workflow where appropriate, then use the check on the most relevant components. SOLIDWORKS documentation notes that Interference Detection is available in Large Design Review mode in current versions, although some result details can be limited in that mode.

Quick checklist before releasing the assembly

• Run Interference Detection after the final mate changes.
• Review every result instead of only checking the count.
• Fix incorrect mates and wrong part configurations first.
• Document intentional interferences such as press fits or simplified threads.
• Run the check again after corrections.
• Update drawings only after the assembly passes the check.

For related design checks, see SOLIDWORKS detailing and drawing techniques before preparing release drawings.

Reference: SOLIDWORKS Help covers Interference Detection from the Evaluate tools, including current notes for assemblies and large design review workflows.