static void rotateAroundAxis(DoubleTransform dtr, DVec3 localAxis, double angle)
    {
        var axis = (dtr.localRotation * localAxis).normalized;
        var rot  = DQuat.fromAxisAngle(axis, angle).normalized;

        dtr.localRotation = (rot * dtr.localRotation).normalized;
    }
 public PhysBodyRecord(DoublePhysicsBody phys_, DoubleTransform dtr_)
 {
     phys = phys_;
     dtr  = dtr_;
 }