public void addCollisionObject(PhysicsCollisionObject obj) {
        if (obj instanceof PhysicsGhostObject) {
            addGhostObject((PhysicsGhostObject) obj);
        } else if (obj instanceof PhysicsRigidBody) {
            addRigidBody((PhysicsRigidBody) obj);
        } else if (obj instanceof PhysicsVehicle) {
            addRigidBody((PhysicsVehicle) obj);
        } else if (obj instanceof PhysicsCharacter) {
            addCharacter((PhysicsCharacter) obj);
        }
    }
adds an object to the physics space
@param obj the PhysicsControl or Spatial with PhysicsControl to add
jme3-jbullet/src/main/java/com/jme3/bullet/PhysicsSpace.java