Hi, I want to use a cube as a transparent container and that all new objects that I add to the world, have the same size as this one

I tried to do it with setBoundingBox but it does not work for me

//Log.d("OBJECT3D", "estoy entrando");
cube = new Object3D(Primitives.getCube(1));
///////////////con un OBJ
try {
spider= Object3D.mergeAll(Loader.loadOBJ(mActivity.getModel3D(),mActivity.getMaterial3D(), 1f));
} catch (IOException e) {

e.printStackTrace();
}
cube.calcBoundingBox();
float[] bb=cube.getMesh().getBoundingBox();
    float xDiff=bb[1]-bb[0];
    float yDiff=bb[3]-bb[2];
    float zDiff=bb[5]-bb[4];
    float s=cube.getScale();
  SimpleVector out = new SimpleVector(xDiff*s,yDiff*s,zDiff*s);

//Log.d("OBJECT3D", "he pasado!");
cube.translate(0, 0, 10);
   
spider.calcBoundingBox();
    spider.setBoundingBox(bb[0], bb[1], bb[2], bb[3], bb[4], bb[5]);
   
    spider.setCenter(cube.getCenter());
   
    spider.build();
    spider.translate(0, 0, 10);
//cube.setTexture("tl");
world.addObject(spider);
world.addObject(cube);

light= new Light(world);
light.setIntensity(128, 128, 128);