Box jitters when sliding along flat convex hull shape

cj3j
Posts: 8
Joined: Wed Nov 20, 2013 6:40 am

Box jitters when sliding along flat convex hull shape

Post by cj3j »

I'm experiencing an issue with a simple box sliding along a flat ground. If the flat ground is another box shape, the box slides nice and smooth. However if it's a convex hull shape, the sliding box pops off the ground a little at the contact points.

The combined friction is 0.49, combined restitution 0.30.
The size of the sliding box is x=1.3 y=0.92 z=0.23. The box is an only child of a compound shape.
Default collision margins (0.04)
Using default collision configuration.

Any suggestions?
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Erwin Coumans
Site Admin
Posts: 4221
Joined: Sun Jun 26, 2005 6:43 pm
Location: California, USA

Re: Box jitters when sliding along flat convex hull shape

Post by Erwin Coumans »

By default, btBoxShape versus btConvexShape only creates one contact point per frame. Over multiple frames there will be more contacts, for stable resting, unless the objects are sliding.

You can enable SAT and create multiple contact points:
for both btBoxShape and btConvexShape, call the initializePolyhedralFeatures method.

Thanks,
Erwin