Simulate Set of Keys with Bullet?

[andymc4997]

Hey everyone, 

So I'm wanting to simulate a set of keys falling onto a table, but I'm struggling getting the sim to run correctly with Bullet. Simply, Bullet will not recognize the holes in the keys and keyless remote active bodies. 

Start of sim:

Result:

As you can see, the items just sort of fall through each other, as if Bullet is ignoring the negative space inside each object and treating them as "shells". Is this just a limitation of Bullet, or is there a way to achieve a realistic result?

I did try using both nCloth and traditional active/passive rigid bodies for this, but both were extremely slow on my PC, probably due to the high poly count of the objects. 

Any help would be greatly appreciated. Thanks in advance!

[mspeer · Accepted solution]

Hi!

The main reason why Bullet is so much faster is because bullet uses simplified geometry for the collision.

You can try to change the collider shape of some or all objects in bulletRigidBodyShape -> Collider Properties to "auto Compound".

If this is still not precise enough you need to use one of the other tools for your dynamic simulation.

[andymc4997]

Ok @mspeer , thanks for your quick reply. I also think I'm gonna have to do a bit better planning for simulations like this, and figure out ways to go lighter with my geometry. The remote piece alone took a long time for Bullet to calculate when I switched everything to Auto Compound. I might even try duplicating the pieces, running a Mesh>Reduce, then trying to run the sim with Bullet. After that, I should be able to just match each piece's transformations. 

Thanks again!