I've got a Revit model containing a few light fixture families. I've brought this into NW and predictably, Clash Detective is picking up the fact that one particular light fixture is made up of multiple composite parts. Nothing I didn't expect.
I noticed on the Rules tab that there is a default rule called "Items in previously found pair of composite objects." Re-running the test with this rule engaged eliminated 6 extra clashes - the ones that were caused by the composite objects. This is a good thing and is exactly what I was looking for...
Then I repeated the whole process from scratch. Exported the model from Revit again, created a new nwc, etc. I ran the first clash test with this rule checked and I noticed the results were the same - 2 legitimate clashes.
What I don't understand here is that the Help file claims that this rule affects composite objects picked up in a previous clash test. If there was no previous clash test (first run on a brand new file), how does it function?