The surface is rebuilt on the GPU: the shader decodes the primitive (octahedral sphere, (2,4,4) square sphere, plane, or folded brush) and adds the displacement map.
Drag to orbit, scroll to zoom. Samples come from export_web_sample.py: raw float32 displacement in
vdm.bin plus the baked PBR maps. The same decode lives in vdm_octahedral.glsl, which the
UE5 and Magnum examples mirror.