What is occlusion culling in Unreal Engine 5?

Occlusion culling is a technique used in computer graphics to reduce the amount of work required by rendering systems. It involves selecting a portion of the scene that is not visible from the camera and discarding it from further processing, which can greatly improve performance.

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Distance-Based Culling

Distance-based culling involves selecting the objects in a scene that are closest to the camera and rendering them first. This can be done using a variety of algorithms, including simple bounding box tests or more advanced spatial partitioning techniques such as octree-based culling. In Unreal Engine 5, distance-based culling is implemented using the Distance-Based Culler component, which allows you to specify the maximum distance at which an object should be considered visible.

LOD Culling

LOD (level of detail) culling involves selecting only those objects in a scene that are visible from the camera and rendering them at their lowest level of detail. This can greatly improve performance by reducing the amount of work required to render an object, as lower-detail models have fewer polygons and textures to process. In Unreal Engine 5, LOD culling is implemented using the LOD component, which allows you to specify the minimum distance at which an object should be rendered at its lowest level of detail.

Combining Distance-Based and

LOD Culling

In many cases, it is possible to combine distance-based and LOD culling to further improve performance. For example, you might use distance-based culling to select the objects that are closest to the camera, and then use LOD culling to render only those objects at their lowest level of detail. In Unreal Engine 5, this can be done using a combination of the Distance-Based Culler and LOD components, which allow you to specify both the maximum distance at which an object should be considered visible (distance-based culling) and the minimum distance at which an object should be rendered (LOD culling).

Conclusion

Occlusion culling is a powerful technique for improving performance in computer graphics, and Unreal Engine 5 provides a range of tools to implement it effectively. By using distance-based and LOD culling algorithms together, you can create highly efficient rendering systems that deliver smooth, fast gameplay even on low-end hardware.