protected void buildObject() {
        if (gObject == null) {
            gObject = new PairCachingGhostObject();
            gObject.setCollisionFlags(gObject.getCollisionFlags() | CollisionFlags.NO_CONTACT_RESPONSE);
        }
        gObject.setCollisionShape(collisionShape.getCShape());
        gObject.setUserPointer(this);
    }
<i>From Bullet manual:</i><br>
GhostObject can keep track of all objects that are overlapping.
By default, this overlap is based on the AABB.
This is useful for creating a character controller,
collision sensors/triggers, explosions etc.<br>
@author normenhansen
jme3-jbullet/src/main/java/com/jme3/bullet/objects/PhysicsGhostObject.java