i've gone over the spec many times, and no where does it say in what coordinate system the mass_frame and velocities are defined in rigid_body and instance_rigid_shape.
There is a small vague comment on instance_rigid_body:
What is the "root" shape?!?Defines the center and orientation of mass of the rigid-body relative to the local origin of the “root” shape.
What is the coordinate system of a rigid body?!
The COLLADA book on page 159 says this:
So does that mean that all the 'target' attributes in <instance_rigid_body> do not set the initial position and orientation of the rigid_body? do all rigid_body instances start with the identity transformation?!The 'parent' is a reference to a <node> in the <visual_scene>, using its id. This allows a physics model to be instantiated under a specific transform node, which will dictate its initial position and orientation......
any help would be most appreciated, since we don't want to get this wrong