walk your data as a voxel world
{ palette:[{name,hex}], blocks:[[x,y,z,colorIdx],…] } — raw voxels
{ pts:[[x,y,z],…], labels?:[…] } or [[x,y,z],…] — 3-D point cloud
{ pts3d:[{v:[x,y,z],p,g}],… } — labeled cloud (HRL format)
{ N, x:[…], y:[…], cls:[…] } — 2-D field (extruded by class)