My geoClipMapping terrain setup has a constant I use to set the mesh resolution. If I set it to 50 or lower, culling works great, and if I set it to 51 or higher, none of the terrain culls. See line 114 of http://github.com/Craig-Macomber/Panda3D-Terrain-System/blob/devchaos/renderer.py:
rezFactor=50
Here it is working properly. You can guess what the nothing culls case looks like.
Everything here uses Bounding Boxes, and they go all the way down to geoms with custom sized bounding boxes. Each ring of LOD is one node with several separate geoms (for culling purposes only). Height is done on the GPU and varies over time, so the boxes are all rather tall.
I’m baffled as to how this could happen. The bounding boxes do depend on rezFactor, but they shouldn’t change much between 50 and 51. I’d been using 80 until I discovered the issue.