How do you use occlusion culling to reduce draw calls in Unity?

2 How to enable occlusion culling in Unity?

Unity has a built-in occlusion culling system that you can enable in the Window > Rendering > Occlusion Culling menu. There, you can set up the parameters for the occlusion map, such as the cell size, the accuracy, and the smallest hole. You can also see the occlusion statistics and preview the occlusion culling in the scene view. To use occlusion culling, you need to mark your objects as static or occluder static, and bake the occlusion map by clicking the Bake button.

3 How to optimize occlusion culling in Unity?

Occlusion culling can improve your performance, but it also has some costs, such as memory to store the occlusion map and CPU time to update it and perform the culling. To optimize occlusion culling, you need to balance these costs with the benefits. When optimizing occlusion culling in Unity, you should use a reasonable cell size that matches the scale of your scene and your objects. A smaller cell size can increase the accuracy of occlusion culling, but also increase the memory usage and baking time. You should also use a low accuracy value and smallest hole value that still provide a good visual result. Occluder static objects should be used sparingly and strategically since they contribute to the occlusion map and occlusion culling, but also increase the memory usage and baking time.

4 How to test occlusion culling in Unity?

To test occlusion culling in Unity, you can use the occlusion culling window and the scene view. In the occlusion culling window, you can see the statistics of your occlusion map and your draw calls, such as the size, the cells, the objects, and the reduction percentage. You can also see the errors and warnings of your occlusion map, such as invalid objects or overlapping cells. In the scene view, you can enable the occlusion culling visualization mode by clicking the Occlusion button. There, you can see the occlusion map in a grid of blue cells, and the objects that are culled in red wireframes.

5 How to troubleshoot occlusion culling in Unity?

Occlusion culling is a powerful technique that can help optimize game performance by reducing draw calls. In Unity, it's easy to set up and test occlusion culling for your game. However, sometimes it may not work as expected or cause issues. Common problems include objects not being culled or culled incorrectly, objects popping in or out of view, and performance getting worse with occlusion culling. To fix these issues, you should check your object settings, rebake your occlusion map, adjust your parameters, limit camera speed or distance, increase accuracy or smallest hole values, reduce cell size or accuracy values, and simplify scene geometry or object hierarchy.

6 Here’s what else to consider

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