nx_derm.nx

nx_derm.nx -- PIPELINE STAGE 4: SKIN AS AN ENVELOPE, computed from the layers beneath it. The industry's fourth stage is "the final visible mesh acts as an envelope, calculating wrinkles and stress maps based on the movement of the inner layers". An audit found ours was the opposite: an INDEPENDENTLY EMITTED SHELL that merely happened to render outermost. Nothing about it was derived from the muscle underneath, so nothing could wrinkle, stretch or slacken when the body moved -- the layer stack had the right topology and the skin was not actually on top of anything. ★THE INVERSION THIS ORGAN MAKES: skin position is no longer authored, it is DERIVED. For each station the skin sits at (muscle radius + fat thickness), so when nx_myo bulges a muscle the skin above it rises BY CONSTRUCTION rather than by a second edit that has to be kept in sync. The envelope invariant -- skin can never sink beneath the muscle it covers -- is enforced arithmetically, not checked afterwards. ★AND THE PART THAT MAKES IT A SKIN RATHER THAN A BALLOON: STRESS. When the underlying surface shortens, the skin over it has more area than it needs and must go somewhere: it slackens and WRINKLES. When the surface lengthens, the skin is stretched taut and smooths out. So wrinkle amplitude is a function of local COMPRESSION, which means wrinkles appear where a body actually creases and nowhere else. nx_derm <muscle_r> <rest_muscle_r> <fat> -> the skin state over that muscle nx_derm selftest license_tier: ORIGINAL expect_exit: 0 No hw writes (Rule 26).