Hi, I was wondering if there is any way that I am not aware of to cache or precalculate the collision data that gets calculated at the beginning of a packed Bullet simulation.

I've got a scene with approx 11,000 rbd objects from a shatter as a packed fractured bullet rbd, and it takes approx 5 minutes to get thru the first frame where it is I assume, building the collision convex hulls for the geo? Is this normal?

I would assume there's some way to cache that and re-use it? but I don't see anything. The startup time on a sim is killing me.

Any ideas?

thx

-redpaw

That sounds very slow for only 11000 objects - it would be a good idea to submit a bug

I figured it out.. I had everything in a group per object , like “piece_#” When it unpacked that, it took a long time, which clued me in, and if i deleted all those groups first before making the packed prim fracture the unpack went significantly faster and so did the build of the collision stuff in the bullet sim as well.

-john

Ah, that makes sense. It's much more efficient to use the ‘name’ attribute to partition the primitives instead of having a separate primitive group for each piece.