Level of Detail (LOD)

Level of detail (LOD) is one of the most important ways to optimize rendering (and performance in general) in a 3D project, along with occlusion culling.

The LOD node

The LOD node provides a simple way of automatically switching between visual representations as the node gets closer or further from the Camera, in order to increase performance.

You might:

  • substitute lower poly count meshes

  • swap several separate meshes for a single approximate mesh

  • swap from a mesh to a billboard

  • turn off particle effects, animations, sounds, scripts according to distance

  • entirely remove visuals in the distance

The LOD node should be added as a parent to whatever you wish to use to show the object, e.g. a MeshInstance. You can place several Spatial derived nodes as children.

../../_images/lod_node_scene.webp

The LOD node will automatically hide and show Spatial children depending on the distance from the Camera.

Tip

You can react to NOTIFICATION_VISIBILITY_CHANGED in scripts to detect when a node has been shown or hidden.

Children are shown in order with the first children shown when closest to the Camera, and the latter children shown when further away.

You can determine the distance at which these swaps occur by setting the lod_range property of Spatial.

Note

Children of the LOD node can in turn have any number of children, of any type. These grandchildren will inherit their visibility as the LOD node operates.

One of the most common cases is to swap between high-poly and low-poly models.

From most detailed (left) to least detailed (right), wireframe view

From most detailed (left) to least detailed (right), wireframe view

Note

Redot 3.x does not currently generate decimated meshes for you. You are advised to generate several versions of a mesh in your modeling program (e.g. using the Decimate modifier in Blender).