nx_skullsdf_region_gate_t334.nx

nx_skullsdf.nx -- the skull as a FUSED SHELL WITH OPENINGS, built in the implicit path. ★WHY THIS EXISTS, from two render cycles of evidence rather than preference. nx_skullgen emits the skull as seven LOFTED TUBES. Rendered, that is seven separate objects sharing a bounding box: the nasal bones float clear of the face, the zygomatic arch is a rod passing through nothing, and the braincase is a balloon with a jaw hanging near it. Moving the tubes closer helps a little and cannot fix the class of problem, because A SKULL IS NOT A SET OF TUBES -- it is one continuous fused shell with holes cut in it. Tubes cannot fuse and cannot have holes. ★THE IMPLICIT PATH DOES EXACTLY THOSE TWO THINGS AND WE ALREADY OWN IT: smooth-union joins bones into one surface, subtraction cuts the orbits and the nasal aperture as real openings, and nx_isosurf's surface_nets polygonizes the result into nx_trimesh. The plan reserved SDF for viscera on the grounds that it cannot resolve an eyelash -- true, and irrelevant to bone, whose features are centimetres. ⚠So this does NOT replace the loft path for skin. It claims the skull only. nx_skullsdf <out.nxmesh> [sex 0-1000] [robust 0-1000] [grid] license_tier: ORIGINAL expect_exit: 0 No hw writes (Rule 26).