Joint orientation: relative to parent joint or world frame?

Technical Support & Q&A Advanced
1

If I access a joint object as follows:
joint = &body->joints[ASTRA_JOINT_LEFT_HAND];
and get orientation (astra_matrix3x3_t ):
&joint->orientation

Is this rotation relative to the parent or to wrf?

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2

In the Unity context, these values seem to all be relative. There is a GameObject in the sample (“JointRoot”) that becomes the parent for all skeleton joints. Simply creating a new Joint as a child of “JointRoot”, using those inputs as “localPosition”, seems to work very well.

You can also position and rotate the “JointRoot” to represent the camera in your scene. You can also counter-rotate the “JointRoot” to account for any rotation of the physical camera.