Hi Maxime! Thanks for the info about Poly Reduction and ideas with ExecutePasses I will try that immediately
I am currently on the latest, R21.115. However I tested this same stuff happening on R20 as well.
Cloners are usually okay as long as they don't reference a spline (which now makes sense knowing about the cache thing).
However, I am right now getting a very strange thing where a cloner and a null with dynamics tag (applied to many children) go from importing normally to not.. depending on how many children are in the Fracture.1 null. But perhaps this is a separate issue. When testing with the manual FBX export, it takes some time.. I am assuming it has to animate the dynamics tag to it's current position before exporting... Perhaps unity does not know how to wait for this operation unless it is very fast. Perplexing why it would have anything to do with the cloner, though, as it is not in any way connected to the Fracture.1 null or the dynamics system. Removing one or the other object results in a successful import into unity. The attached scene fails import into unity unless you delete the cloner, the dynamics tag attached to the null, or at least 10-50 more children of the null.fbxtest_v03.c4d. This is different than the original issue I posted about, where the scene import does not fail, but merely comes in with missing objects.
I will try the ExecutePasses thing now! Thanks again!