setModelBound making my objects disappear

whenever I add the setModelBound my objects all disappear.  Can anyone tell me why?


          Quad buttonQuad = new Quad(buttonName, 40f, 40f);        
          final TextureState ts = display.getRenderer().createTextureState();        
          final Texture texture = TextureManager.loadTexture(
                  getClass().getResource(texturePath),
                  Texture.MinificationFilter.Trilinear,
                  Texture.MagnificationFilter.Bilinear,
                  1.0f,
                  true);
        
          ts.setTexture(texture);
          int textureWidth = ts.getTexture().getImage().getWidth();
         int textureHeight = ts.getTexture().getImage().getHeight();
          ts.setEnabled(true);
          final FloatBuffer texCoords = BufferUtils.createVector2Buffer(4);
          texCoords.put(getUForPixel(0,textureWidth)).put(getVForPixel(0,textureHeight));         
          texCoords.put(getUForPixel(0,textureWidth)).put(getVForPixel(40,textureHeight));
          texCoords.put(getUForPixel(40,textureWidth)).put(getVForPixel(40,textureHeight));   
          texCoords.put(getUForPixel(40,textureWidth)).put(getVForPixel(0,textureHeight));
          buttonQuad.setTextureCoords(new TexCoords(texCoords));
          buttonQuad.setRenderState(ts);
        
      
          buttonQuad.setRenderQueueMode(Renderer.QUEUE_ORTHO);       
   
          buttonQuad.setLocalTranslation(localTranslation);
          buttonQuad.setLightCombineMode(Spatial.LightCombineMode.Off);
          buttonQuad.setModelBound(new BoundingBox() );  //<


THIS is line that removes/doesntshow objects on screen
          buttonQuad.updateModelBound();
         
          buttonQuad.updateRenderState();
          return buttonQuad;

when drawing things in ortho mode, you propably want to set the CullHint to Never.