   Weird behaviour with Bullet Physics
  Hello I have the following problem:I have integrated the bullet physics library into my game engine and experienceda weird behaviour. The collision handling seems to be working properly but as you can se from this videowhen some balls fall onto a plane the are not rotating correctly.Does anybody have an idea what the source of this problem could be?Thanks in advance   
  It looks like you're just computing the rendering transform incorrectly. Can you show us the code for how you convert the bullet world transform into one you use for rendering?   ;  After the physics step has finished I use the motion state of the rigid body to get the world transform.Afterwards I use btTransform::getRotation().getAxis() and getRotation().getAngle()The rotation axis and angle I then use for the call to glRotate;  did you ensure that the angle is in the proper units (radians or degrees)? and that the axis is unit length ? and that the handedness are the same?You know there is any easier way, using bullet. I believe the btTransform class has a member getOpenglMatrix( ); or something like that. You should be able to get a 16 float array out of that, which you should then pass to glMultMatrixf, versus calling translate and rotate separately.glMultMatrixf( GL_MODELVIEW, trans.getOpenglMatrix( ) );Also, your game should probably be making use of a matrix class. To handle all your transformation tasks without depending on glTranslate and glRotate.It would then be wise to make a utility conversion function to go between your matrix and the bullet transform.MyMatrixType ConvertBulletToMy( const btTransform& bt );btTransform ConvertMyToBullet( const MyMatrixType& mt );That way you can initialize the bullet objects from your game transforms, and easily get game transforms from the bullet objects. You matrix type should support a similar function to getOpenglMatrix() so that it can be passed to glMultMatrixf when you need to draw objects.   ;  The problem was the handedness I think.I am now using getOpenGLMatrix and all works finethanks a lot   