Fix the prototype crotch material and loosen the shirt

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,