Wondering if anyone has had this issue? Sometimes a rotational motion blur works fine - but sometimes (same scene, same frame) - it seems to get too excited and the wheel in question is almost transparent as if its going too fast. This is in both IPR and a PV render in C4d R25. Sometimes, stepping back a few frames - then stepping forward again to the same frame is enough to suddenly fix it... Its a bit puzzling. I've attached one that worked and one that was wrong (not many passes on that one). Cheers!