I assumed it, it seems the greater size becomes the ‘assembly root’ (I called it the WeldFather), this behavior shouldn’t be, the Part0 should be the WeldFather. Please be careful when automating things, ROBLOX Design team (someone designed this ‘greater size becomes root’ behavior)
I’ve read threads a year old about this issue now, it doesn’t seem like staff pay much attention to it. Why is ROBLOX’s design team trying to force-tie physics to everything? Staff, you are smart enough to know that that is a hair off impossible in a game. You just need a strong physics engine, not a perfect one, and especially not a system that you force onto people. You were reluctant to remove CollisionFidelity being based on Geometry in CSG I think to preserve a ‘physics environment’, and you’ve spoken passion about making ROBLOX a very physics-associated game, so I suspect this forceful behavior from ROBLOX.
Other threads on this issue:
(first 2 provided by Echo)