rigid body > low poly concave mesh

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toothlesshobo
Posts: 1
Joined: Wed Apr 16, 2014 2:52 am

rigid body > low poly concave mesh

Post by toothlesshobo »

i am running into a problem with large triangles on a concave mesh. i am seeing box shapes, and convex hulls fall through btBVHTriangleMeshShapes and btGImpactMeshShape. see video: https://vimeo.com/92090298

i'm wondering if somebody knows of a way to help prevent this from happening without setting the margins high and/or subdividing the collision mesh more than the render mesh. what functions/classes i should be looking at to understand this better? i'm digging through the code and it's a bit overwhelming..

i am getting this type of problem in my engine using bullet, but figured i could best demonstrate it using blender2.7. it also happens in the demos. i could send the .blend if anyone would like to see it.

**EDIT**
i have discovered that setting m_fixContactNormalDirection = false; in btGjkPairDetector::getClosestPointsNonVirtual seems to fix ConcaveConvexcastDemo, where some boxes would fall through the mesh. is this important, should i leave it enabled?
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