Why Occlusion Culling Boosts Performance

Imagine your game is starting to pile up with hundreds, even thousands, of unique assets that need to get rendered at runtime, and as you go to run the game, it takes WAY too long to load just a small chunk of the world, or worse, it crashes your game! What do you do now? Thankfully, there’s something called occlusion culling that can prevent that from happening. What is occlusion culling, you may ask? Occlusion culling only loads and renders everything in front of the camera, saving your GPU some HP. And today I will be showing you how you can get that set up in your Unity projects!

Occlusion Culling works only on elements that are static or are viewed as static. In my project Scene, I’m going to turn all the elements under — STATIC — to be part of this occlusion culling process. To do that, we have two options. The first option is to turn on Occluder Static and Occludee Static tags.

The other option is to turn on everything except for Contribute GI. That is what I will go with in my Scene as I want the selected elements from earlier to have the other static tags with them.

Now that I have these elements set with those tags, we have to bake this data.

Now that its baked, check out the difference between the Scene (top) view and the Game (bottom) view as I rotate the Camera. Everything in front of the camera is rendered but everything that isn’t in front of it is not rendered.

Pretty neat huh? Now the last thing you might notice as you add this to your own projects is that some elements that are static are being considered to be dynamic and therefore not culled. The way to fix this is to go to Bake in the Occlusion tab and change the value of Smallest Occluder by 1 or 2 increments.

And that’s how you set up Occlusion Culling your Unity projects! I hope this helps and Happy Dev-ing!