Different types of LODs:
### CPU LOD group
This toggle an entire subtree on the cpu side. For example:
```yaml
- "root":
lod_cutoffs: [0.5, 0.3]
cpu_lod: 0
children:
- "a":
lod_group: ()
lod_visible: true
- "b":
lod_group: ()
lod_visible: false
```
### Mesh lod