A character has arrived as separate body, garment and hair meshes since the
pipeline stopped joining them — but nothing recorded which was which, so every
system downstream re-guessed from the material. That guess ("untextured and
nearly black means ink") had already rendered the mannequin's flat yellow body
as a black silhouette once.
The question is answerable once, at build time, where the mesh, the weights and
the skeleton are all in hand. tools/surface_map.py answers it three ways, in
order of how much it trusts them: the material name, which on VRoid exports is
formal and on hand-authored models is still explicit; the weights, which are
decisive when the name says nothing — a surface pulled by the skirt chain is a
skirt whatever it is called; and the material flags, which catch the model's own
line-work. The answer goes in the rig sidecar next to the roles and the chains,
and SkinSurfaces reads it.
All eighteen of Taila's surfaces, and every surface of the other five skins,
now resolve from the table with nothing falling through to the heuristic
(debug/surface_class_check.gd). The heuristic stays as the fallback, which is
the one job it was ever right for.
What that buys immediately is per-class art direction, which was impossible
while every surface had to take numbers calibrated on skin. Hair takes a much
thinner line — at the body's 5 mm each strand's hull swallows its neighbour and
the head reads as a solid dark cap. Cloth takes a heavier line and a crisper
terminator, because a garment's silhouette is most of what separates a character
from the background at range. Accessories take the heaviest. `body` is unchanged
on purpose, so the look this was all calibrated against does not move.
That required moving the outline from the instance to the surface: Miku's body,
face and hair are three surfaces of ONE mesh, so an instance-wide overlay could
only ever give all three the same weight.
Two things found on the way, fixed here because they are one line each: the
surface classifier skips meshes with no vertex groups, which drops the stray
42-vertex Icosphere that rides inside every shipped skin — two older tools
already skipped it by spelling its name — and load_model now clears _rig_info,
which a model with no skeleton used to inherit from the last character loaded.
Co-Authored-By: Claude Opus 5 <[email protected]>
The finger roles only reach the runtime through <model>.rig.json, so a
character whose sidecar predates them keeps flat, open hands however good
the pose layer is. Aria, Momo, Miku and the Mannequin re-imported; all six
skins now carry 10 finger chains.
Verified on the Mannequin, which is untextured and so the clearest
diagnostic of the three checked: stock at the shoulder, trigger hand on the
grip, support hand out on the handguard, both fists closed, arms not
crossing. Its arm is a full 0.524 m against Taila's 0.468 and it scales the
weapon independently — 0.231 m of hand separation against her 0.217 — with
the slide-back loop never firing on either.
Known remaining: the support hand's wrist roll leaves the hand hanging a
little under the handguard rather than wrapping it squarely. The grip
POSITION is right on every character; it is the roll about the barrel that
wants another pass.
Co-Authored-By: Claude Opus 5 <[email protected]>
WEAPON MOUNT, all models. set_weapon() seated the gun with a fixed
rotation_degrees = (0, 90, -90). A bone attachment is expressed in the
BONE's axes and no two rigs agree on those, so one constant mounted the
weapon differently on every character. It never needed to be right: the
pose layer aims the gun by rotating the wrist until the weapon's forward
lies on the aim line, so the identity means "forward is the hand bone's
-Z", which is true on any rig, and the wrist absorbs the roll. The grip
now sits at the bone origin, so the gun is in the hand rather than at an
offset from a differently-oriented bone. Verified by render on kiyoko:
rifle shouldered, both hands on it.
FACING. flatten_and_scale() now measures toes-versus-ankles and snaps the
character to face Blender -Y, the convention the runtime's blanket flip is
built around. Kiyoko was 180 degrees off. Snapped to the nearest quarter
turn so splayed feet in a rest pose are not read as a turned character.
MIKU. Re-imported without --grow-cloth. Her grown hair chains were the
cause of the stretching: cloth_bones.py clears a vertex's body weights and
re-assigns it to the fitted polyline, so a poor fit does not degrade to
"stiff", it degrades to "torn". She now has no hair simulation — stiff but
correct — until that tool blends against the weights it replaces instead
of destroying them.
ARIA'S SKIRT IS NOT SIMULATED. Worth recording plainly, because it looks
better than Taila's and the obvious conclusion is the wrong one: aria has
ZERO cloth chains. Her skirt never clips because it is rigidly skinned and
follows the legs it is weighted to. There is nothing to port to Taila
except switching her simulation off.
Co-Authored-By: Claude Opus 5 <[email protected]>
Miku shipped with 0 cloth chains against Taila's 35, so her twin tails
hung off her skull like a helmet. Nothing downstream could fix it: the
spring solver simulates cloth BONES, and a garment with none is welded to
whatever body bone it was weighted to. Every auto-rigged model is in that
state, and her source was an unrigged mesh.
tools/cloth_bones.py builds them, which is the job a technical artist does
by hand on a model like this. It finds the geometry by MATERIAL SLOT — the
artist already answered which surface is hair, and on a joined mesh (what
the auto-rig leaves behind) the slot is the only separation left. Hair is
split into connected islands, because a strand is a connected piece of
surface and clustering by position would merge two ponytails passing near
each other. A skirt is split into radial wedges instead, because a skirt
is ONE connected surface and islands would return the whole thing as a
single piece — the bell-shaped failure. Each clump gets a polyline fitted
down its middle by binning vertices by distance and taking centroids, so
the chain follows the piece's own curve rather than cutting the corner on
a bend, and vertices are re-weighted onto it while the first 22% keeps its
original body weight so the scalp stays on the skull.
On Miku: 19 chains, 57 bones from one `hair` slot. Sidecar 0 -> 19 chains.
Idle stability 0.007-0.018 deg/frame. Mesh intact, verified by render.
Opt-in, via `pipeline.py --grow-cloth`, and run before the retarget so
describe_rig() finds the chains by name exactly as it would an artist's.
Known limits, recorded in the skill: it cannot find a garment sharing a
material with the body (Miku's skirt is on her `body` slot, so she got
hair and no skirt), and grown chains are a fallback — an artist's chains
carry intent that no geometric fit recovers.
Co-Authored-By: Claude Opus 5 <[email protected]>
Nicholas Butzke