How to check if two parts are hitting each other (Interference) in SolidWorks?
Short Answer
Yes — in SolidWorks, the fastest professional way to check whether two parts are hitting each other is with Interference Detection in an assembly. It highlights overlapping volumes between components and lets you review ignored contacts or multibody results. Limitation: it only works reliably when the parts are positioned correctly in the assembly.
What You Need to Know Before
Warning: Interference Detection can report false issues if components are intentionally mated with slight overlap, imported geometry is faulty, or bodies are not fully resolved. A very common failure is checking a lightweight or outdated assembly state and trusting the result without rebuilding first.
How to Check Interference in SolidWorks
Command: Interference Detection
Shortcut: No default keyboard shortcut
Quick Steps:
- Open the assembly, then go to the Evaluate tab on the CommandManager and click Interference Detection.
- In the PropertyManager, select the components to check or leave the full assembly selected.
- Turn on Treat coincidence as interference if you need to catch touching faces, then click Calculate to review the interfering parts and volumes.
Variables & Settings
Key Setting: Treat coincidence as interference
Expert Setting: When enabled, SolidWorks flags components that merely touch as interfering. Leave it off for normal hard-overlap checks; turn it on when validating tight-clearance designs, seal contact, or no-gap assembly requirements.
Why it Fails
- Cause 1 (Geometry): Imported or corrupt solid geometry can create invalid body intersections or missed interference results.
- Cause 2 (layers/Locks): Components may be lightweight, suppressed, or not fully resolved, so SolidWorks does not evaluate them correctly.
- Cause 3 (Command/Logic): Running the check on the wrong configuration, without rebuild, or with coincidence settings disabled can hide real contact problems.
Quick Fix & Best Practice
- Quick Fix: Rebuild the assembly with Ctrl+B or Ctrl+Q, resolve lightweight components, then rerun Interference Detection with the correct configuration active.
- Manager’s Verdict: Use Interference Detection as the standard first-pass validation tool in assemblies. For moving mechanisms, do not rely on it alone—combine it with clearance checks or motion study when dynamic contact matters.
FAQ
How do I check if parts are only touching, not overlapping?
Enable Treat coincidence as interference in Interference Detection.
Can I run interference detection on a multibody part?
Yes, but the most common workflow is to check it in an assembly for clearer component-level results.
Why is SolidWorks not showing an expected interference?
The assembly may need rebuild, the parts may be lightweight, or you may be checking the wrong configuration.
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