nx_meshcheck.nx

nx_meshcheck.nx -- MESH INTEGRITY, the check nothing in this estate performed. WHAT THIS IS AND WHY IT IS MISSING-SHAPED. The estate GENERATES meshes -- surface nets from SDFs, layered bodies, skulls, faces -- and measures them for SHAPE AGREEMENT against a reference (nx_mmdev_lib md_measure, exact per-vertex deviation) and for anatomical plausibility. Nothing asks the prior question: IS THIS MESH STRUCTURALLY WELL-FORMED AT ALL. A mesh can sit perfectly on its reference and still have inverted winding on a third of its faces, an edge shared by three triangles, or four hundred vertices no triangle references -- and every one of those shows up to the eye as junk while every ruler we own reports agreement. THE ONE PRIOR CHECK, AND WHY IT IS NOT ENOUGH. nx_faceanat_mesh_gate carries a WATERTIGHT tooth using the Euler characteristic: for a closed genus-0 triangle mesh V = F/2 + 2, tested within a tolerance of F/16. That is a real check and it is NECESSARY, NOT SUFFICIENT, for two reasons the tooth itself cannot see. First, Euler is a SINGLE SCALAR over the whole surface, so compensating defects cancel: punch a hole and add a handle and the characteristic is unchanged. Second, it is computed on ONE subject inside ONE gate, so it is a tooth rather than a ruler -- no other mesh in the estate is ever asked. This organ counts the actual incidences instead, which is the direct measurement Euler is a proxy for. EVERY DEFECT CLASS IS COUNTED SEPARATELY AND CARRIES A WORKLIST. A single is-it-broken boolean is not actionable, and two defect classes with opposite remedies must never share a counter: a boundary edge means the surface is OPEN, a three-face edge means it is NON-MANIFOLD, and an inconsistently wound pair means the surface is CLOSED but its normals disagree. Those are three different repairs. Each class reports its count AND the first offenders by index, and says so when that list is a PREFIX rather than the whole set. PURE INTEGER, NO FLOAT ANYWHERE. Coordinates are caller-defined integer units (micrometres is the estate's habit). The area test is an exact integer cross product, so a degenerate triangle is PROVEN degenerate rather than declared so by an epsilon somebody picked. license_tier: ORIGINAL No hardware writes (Rule 26). Reads buffers, opens nothing.