These runtime warnings are not helpful, it may be intentional to have
an object that sometimes does not contain entities of a specific kind,
without changing the drawmode when this happens.

```
warning: numIndices is 0 in renderobject: VolumeMeshNodeVertices
warning: numIndices is 0 in renderobject: VolumeMeshNodeFaces
warning: numIndices is 0 in renderobject: VolumeMeshNodeEdges
```