Now let’s look at how well the occlusion culling is working with the Tome data you just computed. To visualize how well the culling is performing you can highlight all the occluded objects with red color. See image below.
Now, in both views, you can see all the hidden objects shaded in red. By default, the left hand view port is the main occlusion culling camera and the right hand view port is a debugging viewport used for visualizations.
The Query Statistics pane show you how many milliseconds it takes to process the visibility query over time and how many objects are visible and hidden.