RTR is at its most efficient when there is nothing!

Before Rendering: CPU → CPU → GPU

Occlusion process - builds up a list of all visible models/objects

It happens per object - not per polygon

1. Distance Culling (LOD)

2. Frustum Culling

3. Precomputed Visibility

   • divide the scene into a grid, each grid cell remembers what it can see

   

4. Occlusion Culling

   • accurately checks the visibility state on every model (heavy)