@VehiclePhysics@vuchithien95@VVaryvdin The physx documentation is quite clear about the definition of deltax:
"where deltax is the deviation from the defined rest pose.."
@VehiclePhysics@vuchithien95@VVaryvdin This is actually very simple - it all depends on the definition of zero displacement. We are free to choose any definition we like as long as we correct for that with an appropriate constant.