Can you check for physical interferences between two moving parts in Autodesk Fusion?
Short Answer
Yes. In Autodesk Fusion, you can check for physical interferences between two moving parts using contact set during a motion study, which is the most common professional method for dynamic interference checking. It helps detect collisions while dragging or driving joints. Limitation: it is slower on large assemblies.
What You Need to Know Before
Warning: Contact detection in Fusion only works reliably when components are set up as separate components with proper joints or motion. A very common failure is testing imported bodies with no assembly relationships, which gives misleading collision behavior or no motion at all.
How to Check for Physical Interferences Between Moving Parts
Command: Contact Set
Shortcut: None
Quick Steps:
- In the Browser, make sure the parts are separate Components, then create the needed motion using Assemble > Joint on the toolbar.
- In the Browser, Ctrl-click the two components, right-click, and choose Contact Set.
- Drag the component or drive the joint from right-click Joint > Drive Joint, and Fusion will stop motion when the parts physically contact. If needed, enable Contact Solver in the assembly context.
Variables & Settings
Key Setting: Contact Solver toggle
Expert Setting: The Contact Solver must be enabled for Fusion to calculate collision response during motion. If it is off, components can pass through each other visually even when a Contact Set exists.
Why it Fails
- Cause 1 (Geometry): The parts are modeled as bodies instead of separate components, so Fusion cannot evaluate assembly motion and contact correctly.
- Cause 2 (layers/Locks): One or both components are grounded, rigidly constrained, or captured in a way that prevents expected movement during the test.
- Cause 3 (Command/Logic): The user runs a static interference idea on moving parts without assigning a Contact Set, so Fusion shows overlap only after penetration instead of preventing collision during motion.
Quick Fix & Best Practice
- Quick Fix: Convert the parts into proper components, apply a real Joint, then assign Contact Set and test with Drive Joint.
- Manager’s Verdict: Use Contact Set for realistic motion clearance checks in small to medium mechanisms. For large assemblies, use it only on critical part pairs because performance drops quickly.
FAQ
Can Autodesk Fusion detect interference without motion?
Yes, you can use static interference checking, but it will not simulate moving contact.
Do I need joints before using Contact Set?
Yes, in most professional workflows, joints are needed so the parts move predictably.
Why do parts still pass through each other in Fusion?
Usually the Contact Solver is off, or the parts are not set up as proper components with valid motion.
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