In theory, any opaque object can act as an occluders. However, most in-game models are too complex to be considered as occluders. DigitalRune Graphics therefore uses "occlusion proxies". This means, occluders are artist-authored triangle meshes. These lightweight triangle meshes are used in place of the actual models during occlusion culling. Occluders are usually created as part of a model in the 3D modeling tool (see Asset Creation: Occluders). But they can also be created at runtime using code.

The class Occluder represents the occluder geometry. The Occluder can be assigned to a mesh (see property MeshOccluder) or to an OccluderNode.

The following scene nodes act as occluders during occlusion culling:

• An OccluderNode positions an occluder within a 3D scene. The sole purpose of this scene node is to provide an occluder for occlusion culling.
• A MeshNode acts as an occluder when its mesh has an occluder (see property MeshOccluder).
• A LodGroupNode acts as an occluder when LOD0 (the highest level of detail) has as an occluder.

See Asset Creation: Occluders to learn how to import occluders using the content pipeline.