[QUESTION] What is the joint angle target for JOINT_MODE_TARGET_POSTION?

[lisiyao21]

Hi! Thanks for this great work! I wish to know what is the target for joint_6d angles when using JOINT_MODE_TARGET_POSTION?
When I use joint_6d with only 3 rotational freedom, should the "positional" target here be joint rotation?

But It seems not to be axis angle. In XPBD integrator code:

    rel_q = wp.quat_inverse(q_p) * q_c
    qtwist = wp.normalize(wp.quat(rel_q[0], 0.0, 0.0, rel_q[3]))
    qswing = rel_q * wp.quat_inverse(qtwist)

    # decompose to a compound rotation each axis
    s = wp.sqrt(rel_q[0] * rel_q[0] + rel_q[3] * rel_q[3])
    invs = 1.0 / s
    invscube = invs * invs * invs

    # handle axis-angle joints

    # rescale twist from quaternion space to angular
    err_0 = 2.0 * wp.asin(wp.clamp(qtwist[0], -1.0, 1.0))
    err_1 = qswing[1]
    err_2 = qswing[2]

When setting joint_act, should I first transform the rotvec (axis angle) to such decomposition? thanks!