code: public void build(Node rootNode, SimpleApplication app) {
          house = (Node) app.getAssetManager().loadModel(urlResource);
          house.setUserData("ID", houseId);
          house.setUserData("ROLE", "House");
          System.out.println("\n\nBuinding " + house.getName());
          physicalEntities = (Node) house.getChild("PhysicalEntities");
  
          Node physicalStructure = (Node) house.getChild("Structure");
          visualStructure = (Node) physicalStructure.getChild("Visual");
          physicsStructure = (Node) physicalStructure.getChild("Physics");
          logicalEntities = (Node) house.getChild("LogicalEntities");
          spatialCoordenates = (Node) logicalEntities
                  .getChild("SpatialCoordenates");
  
          initSpatials();
          initLights(app);
  
          app.getStateManager().getState(BulletAppState.class).getPhysicsSpace().addAll(physicalEntities);
          app.getStateManager().getState(BulletAppState.class).getPhysicsSpace().addAll(physicsStructure);
  
          rootNode.attachChild(house);
  
          PhysicsUtils.updateLocationAndRotation(house);
      }
docs: Build the house with physics properties and add it to rootNode (the
  world).
  
  @param rootNode
  @param assetManager
  @param physicsSpace