Real-Time Physics Simulation Forum

Thanks! I read Brian's thesis years ago which is why I was looking to use Bullet for this project. I'm fully aware of the underlying theory. I've implemented featherstone's ID/FD algorithms twice at this point for proprietary systems because the opensource solutions back then were not flexible, suff...

Also, eigen decomposition or svd work fine to get the principle axis and the rotation from the inertia tensors orientation to the principle axis. Since inertia tensor are 3x3 and symmetric there is a closed form solution. Are you trying to compute the rotation that would diagonalize the matrix? Yes,...

Example inertia tensor: 0.00076275 -0.00047298 0 -0.00047298 0.0019185 0 0 0 0.0022293 btMatrix3x3 inertia(0.00076275, -0.00047298, 0, -0.00047298, 0.0019185, 0, 0, 0, 0.0022293); btQuaternion q = btQuaternion::getIdentity(); inertia.extractRotation(q); The omega computed in extractRotation is 0 on ...

Before my questions I have a little reference diagram attached that I'll reference. The purple frame is the world coordinate system. The red frame is the center of mass and principle axis orientation. The black frame is a revolute joint location, the axis is along the z in this image. The gold frame...