Fix the prototype crotch material and loosen the shirt

MEMORY.md

@@ -33,9 +33,9 @@ canonical implemented-features list in `docs/development-status.md`.
   points/weights, removes the rig, applies the helper MASK, scales to 1.81 m, retargets the A-pose
   arms to the contract wrist, cuts the neck at 1.505, decimates, bisects the clothing boundaries,
   paints the five slots, adds a short neck flare, project hands, rounded shoes and cuffs, the
-  accepted head and the 14-bone contract armature. Current output: **15,317 tris / 13,507 glTF
-  verts / 13,513 seam-split verts / 1.810 m / 14 bones / 10 materials**; `inspect` clean and feet
-  grounded. The torso is inflated radially by 8% between z 0.84 and 1.40 to loosen the shirt. The
+  accepted head and the 14-bone contract armature. Current output: **15,317 tris / 13,690 glTF
+  verts / 13,702 seam-split verts / 1.810 m / 14 bones / 10 materials**; `inspect` clean and feet
+  grounded. The torso is inflated radially by 12% through z 0.72–1.40 to loosen the shirt. The
   neck is a radial cut of the decimated column bridged by a four-ring, 20-segment lathe (lower
   rings painted cloth, reads as a crew neck); the ankles are hidden by a bevelled 0.11 m shoe
   shell, an inset 0.111 × 0.286 m sole, a tongue and a 0.08 m pant cuff. Sleeve cuffs use the
@@ -45,10 +45,14 @@ canonical implemented-features list in `docs/development-status.md`.
   brace, shelf or donut, and vertex smoothing tore the open collar boundary into a dark hole. An
   untucked shirt-hem band at the hips also failed: it read as a hanging white flap at the crotch.
   Protruding flat sole plates read as skates/bricks and were replaced by an inset sole under a
-  rounded shell; laces were dropped for triangle budget. Remaining polish: V-shaped shirt hem at
-  the crotch, partly loosened shirt, angular thigh facets; a proper shirt shell is the fix. The
-  prototype uses flat slot colours because the one-shot MPFB UV unwrap does not match the per-slot
-  NPC atlases. Renders: `tmp/npc-parts/mpfb_proto/renders74/`; body-only: `body_only.glb`.
+  rounded shell; laces were dropped for triangle budget. The neck skin rule needed a `z > 1.35`
+  guard: without it the `radius < 0.08` test painted skin at the crotch. Lowering the hem to
+  z 0.80 (unitard), tilting it up at the front (high-cut swimwear) and a 13% hem flare (peplum)
+  were all rejected; the remaining crotch V is the dark hollow under a body-painted shirt, and a
+  separate loose shirt shell is the real fix. Remaining polish: crotch V, partly loosened shirt,
+  angular thigh facets. The prototype uses flat slot colours because the one-shot MPFB UV unwrap
+  does not match the per-slot NPC atlases. Renders:
+  `tmp/npc-parts/mpfb_proto/renders82/`; body-only: `body_only.glb`.
 - **Project agent skills (2026-11-03):** two tracked skills live in `.agents/skills/`:
   `gig-line-blender-asset-contract` and `gig-line-release-qa`. They are guidance only,
   add no runtime dependency and are referenced from `tools/README.md`. The third-party

TODO.md

@@ -203,9 +203,10 @@ owner reviews the silhouette and a production integration decision is recorded.
       apply the helper MASK, scale to 1.81 m, retarget the A-pose arms to the contract wrist
       (`x=±0.27`, `z=0.78`), cut the neck at 1.505, decimate, bisect the clothing boundaries, paint
       the five slots, add a short neck flare, project hands, rounded shoe shells, cuffs, the
-      accepted head and the 14-bone armature. Current output: **15,317 tris / 13,507 glTF verts /
-      13,513 seam-split verts / 1.810 m / 14 bones / 10 materials**; `inspect` clean, feet grounded.
-      The torso is inflated radially by 8% between z 0.84 and 1.40 so the shirt is less skin-tight.
+      accepted head and the 14-bone armature. Current output: **15,317 tris / 13,690 glTF verts /
+      13,702 seam-split verts / 1.810 m / 14 bones / 10 materials**; `inspect` clean, feet grounded.
+      The torso is inflated radially by 12% through z 0.72–1.40 (tapering out at the collar) so the
+      shirt reads as fabric rather than body paint.
 - [x] Replace the spiky decimated MPFB hands with the project palm/finger primitives, straighten the
       splayed MPFB feet so the shoes point forward, and use rounded shoe shells + cuffs instead of
       flat blocks. Use flat slot colours in the prototype because the one-shot MPFB UV unwrap does
@@ -228,11 +229,20 @@ owner reviews the silhouette and a production integration decision is recorded.
       for triangle budget after they proved too small to read.
 - [x] Reject the untucked shirt-hem band: both the 0.09 m and 0.12 m cloth cylinders read as a
       hanging white flap at the crotch. The V hem needs a proper clothing shell, not a band.
-- [ ] Owner reviews the updated MPFB body renders (`tmp/npc-parts/mpfb_proto/renders74/`).
-      Remaining known defects: white shirt hem still forms a V at the crotch, the shirt is only
-      partly loosened by the 8% torso inflation, and the 2k-tri body budget leaves some angular
-      thigh facets. A shirt shell is the proper fix for the first two; these are polish, not
-      blockers for the body direction.
+- [x] Fix the neck material rule: the `radius < 0.08` skin test had no Z floor, so it painted a
+      skin patch at the crotch. It is now guarded to `z > 1.35`; the crotch stays pants.
+- [x] Reject three cheap hem fixes: lowering the shirt to z 0.80 turns it into a unitard; tilting
+      the hem up at the front reads as high-cut swimwear; a 13% hem flare reads as a peplum.
+      The remaining V is the dark crotch hollow under a body-painted shirt, not a slot bug.
+- [ ] Owner reviews the updated MPFB body renders (`tmp/npc-parts/mpfb_proto/renders82/`).
+      Remaining known defects: the crotch hollow still reads as a V under the shirt hem, the
+      shirt is only partly loosened by the 12% torso inflation, and the 2k-tri body budget leaves
+      some angular thigh facets. A separate loose shirt shell is the proper fix for the first
+      two; these are polish, not blockers for the body direction.
+- [ ] Build a separate loose shirt shell (open hem, shaped to the hips) instead of body-painted
+      cloth. It must fit in the 683 spare triangles or come with a head/body triangle rebalance.
+- [ ] Rebalance the triangle budget before rollout: 683 spare is below the ~1,200 the firefighter
+      and hoodie variants need. Protect the head budget first; do not lower the accepted face.
 - [ ] Fix the low-budget seams before any rollout: weld the torso/hip/arm components after the
       bisects, protect the hip/knee loops during decimation (or rebalance head/body triangles).
 - [ ] Record the production integration decision: either bake the approved MPFB body to a committed

docs/npc-model-sourcing.md

@@ -57,12 +57,15 @@ a second face implementation.
 The current local MPFB full-body prototype (`tmp/npc-research/build_mpfb_npc.py`) assembles the
 accepted head on an MPFB 2.0.18 body at **15,317 / 16,000 tris**, 1.810 m, 14 bones and 10
 materials, with project hands, bevelled shoe shells with inset soles and tongues, pant cuffs,
-cloth sleeve cuffs and flat slot colours. The torso is radially inflated by 8% between z 0.84 and
-1.40 to loosen the shirt. It is a review candidate, not a shipped asset. The neck is a radial cut
+cloth sleeve cuffs and flat slot colours. The torso is radially inflated by 12% through z 0.72–1.40
+to loosen the shirt. It is a review candidate, not a shipped asset. The neck is a radial cut
 of the decimated column bridged by a four-ring, 20-segment lathe (lower rings painted cloth,
 reading as a crew neck); the ankles are hidden by 0.11 m shoe shells and 0.08 m pant cuffs, and a
-light smoothing pass softens the closed thigh/hip region. Remaining polish: a V-shaped shirt hem
-at the crotch, a partly loosened shirt and angular thigh facets; a proper shirt shell is the fix.
+light smoothing pass softens the closed thigh/hip region. The neck skin test is guarded to z >
+1.35 so it cannot paint the crotch. Remaining polish: the crotch hollow still reads as a V under
+the shirt hem, a partly loosened shirt and angular thigh facets; a separate loose shirt shell is
+the fix. Lowering the hem to z 0.80, tilting it up at the front and a 13% hem flare were rejected
+as a unitard, high-cut swimwear and a peplum respectively.
 A torus collar, cloth cylinder collar, skin neck-blend sphere, destructive vertex-smoothing pass
 and untucked shirt-hem band were tried and removed because they read as a brace, shelf, donut or
 hanging flap, or tore a hole at the collar. Protruding flat sole plates read as skates or bricks,