It was the SKIRT, not the legs. Every leg check I ran hid the skirt to see the
thighs, so I was never looking at what is actually on screen. Rendering the full
model side-on shows it immediately: at rest the skirt is a flared shape with
real volume, and the moment the legs split for a run or a jump it collapses flat
against the body. The lower-body silhouette loses its shape, which reads as the
legs squashing.
Cause: the skirt is weighted to BOTH thighs. At a split stride the two thighs
pull it in opposite directions and linear-blend skinning averages them, so the
skirt is dragged inward and flattened. The earlier repair deliberately left it
that way, on the reasoning that a skirt should be free to drape across both
legs — correct in principle, wrong at these stride angles.
Draping cloth now hangs from the hips: vertices that clear both leg bone chains
keep at most 20% leg influence and the rest goes to DEF-hips, so the skirt holds
its shape and swings as a unit. Limb vertices are still snapped to one leg, so
the two are now modelled differently on purpose.
Bounded ABOVE THE KNEE. The first attempt used distance from the bone chain
alone, and chunky boots sit further from the ankle than the limb radius, so they
read as "drape", lost their leg weight and trailed off the hips — the legs came
out far worse than before. A skirt hem is above the knee; boots and stockings
are not.
Legs unchanged by this: knee cross-section stays 0.99, and the knee helper work
from the previous commit is intact. Taila snaps 4024 vertices, Miku 670.
FSM tests 11/11, spawn smoke test 0 failures.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
