nx_gsplat_frommesh_gate.nx

nx_gsplat_frommesh_gate.nx -- THE GATE FOR MESH -> GAUSSIANS (gs_from_mesh, landed 2026-09-04). The subject is the ingest edge of the splat lane: the estate could render, fit, densify and cage-bind gaussians but could not MAKE them from a mesh, so an authored sculpt could not enter the representation. ★ANTI-VACUITY IS THE POINT OF THIS FILE. A converter that emitted one fixed blob per triangle, ignored the density argument, painted every splat one colour and picked a constant radius would still "produce gaussians" and would pass any tooth that only counted them. So the load-bearing teeth are the ones such an implementation FAILS: density must move the count (T2), density must move the radius INVERSELY (T6), two faces of different size must get the SAME radius at one density (T7 -- uniform coverage is the whole reason the radius is derived rather than picked), and a three-coloured face must yield more than one splat colour (T5). ⚠T6/T7 ARE AN ARITHMETIC IDENTITY, NOT A HOPE: side = isqrt(density*area/GFX^2) and rtan = isqrt(area/nsamp), so rtan reduces to GFX/isqrt(density) -- INDEPENDENT of area. That is why a bigger face gets more splats of the same size instead of bigger splats, and it is checked as an identity. MEASURED on the first run: rtan 32 at density 1024 and 16 at 4096, which is GFX/isqrt(density) exactly. ⚠NEGATIVE CONTROLS CARRIED: an empty mesh must yield nothing rather than fabricate (NC1), and a degenerate zero-area triangle must be skipped without crashing and without inventing a surfel (NC2). ⚠⚠EVERY CONJUNCT IS BUILT WITH NESTED ifs, NEVER WITH gv_env_pair. That helper PRINTS a pair and RETURNS 0, so passing it as a condition feeds the tooth a constant zero. v1 of this gate did exactly that and read 7/12 RED with `[1,1]` printed ahead of every failure -- the pair values proving BOTH conjuncts were true while the tooth recorded FAIL. A helper whose return value is not its meaning is the cheapest way to build a gate that lies in the safe direction. nx_gsplat_frommesh_gate license_tier: ORIGINAL expect_exit: 0 No hw writes (Rule 26).