Fixes the two root causes behind four of the seven reported breakages, and
rejects the source that cannot be fixed.
STAND UP FIRST. flatten_and_scale() now derives the up axis from the
skeleton and rotates the model upright before measuring anything. Aria and
Momo are correct: 1.75 m tall, 1.43 x 0.41 and 1.52 x 0.39 across, verified
by render.
The up vector is measured from the FEET to the HIPS, not from the hips to
the head. The head is not a reliable landmark — the spine walk ends on the
last non-cosmetic bone in the chain, which on a rig with a facial skeleton
can sit BELOW the hips. Momo's did, so the first cut of this fix stood her
neatly on her head: right size, right proportions, upside down. Feet cannot
be mistaken.
REACH BONES BY ROLE. SkinnedPlayerModel gained _role_bone(), and set_weapon
uses it. Four characters could not hold a gun because one hardcoded lookup
knew three spellings and their hands are called "Right wrist" and
"J_Bip_R_Hand" — both resolved perfectly in the sidecar the whole time.
HIKARI IS REJECTED. She now fails the gate: her feet and spine disagree
about which way is up, so the stand-up correction cannot resolve her
either, on top of zero-length cosmetic bones and a second armature that was
smuggling its own clips into the export. That is not a tuning problem, it
is a file that has been through two toolchains. De-registered and removed
rather than shipped broken — which is what the gate is for.
Six GLB skins remain, all passing. Smoke 0 failures, 11/11 movement tests.
Still open, recorded in the skill: kiyoko faces backwards, miku's grown
hair stretches under animation, the mannequin's rifle hold does not
convince, and taila's front skirt clipping.
Co-Authored-By: Claude Opus 5 <[email protected]>
Seven characters shipped "All checks passed" and four were visibly broken
in game — lying on their backs at seven times scale, facing backwards, or
holding a gun that floated near their chest. Nothing in the suite was
wrong; it just never asked the questions that mattered. That distinction
is the whole lesson, and it is now written down in the skill as
references/failure-modes.md, generalised per failure.
Two root causes are measured and certain:
- flatten_and_scale() normalises the bounding box along Blender Z because
Z is up. For a model that arrives lying along Y that measures the
character's THICKNESS, so it scales by ~7 and leaves them on their back.
One assumption, both symptoms. The trap is that the normalised number
always comes out right — the exporter maps Blender Z to glTF Y, so "is
the height 1.75" passes on a character who is 7.5 m tall lying down.
All three casualties are VRM files that went through a Blender
round-trip and came back with a baked axis rotation.
- SkinnedPlayerModel.set_weapon() finds the hand with three hardcoded
spellings, which match none of the four non-Rigify rigs — their hands
resolve perfectly in the sidecar as "Right wrist" and "J_Bip_R_Hand".
When it misses, the weapon is parented to the model root at a fixed
chest offset, so it is not attached to the character at all. Same class
of bug as the leg check that name-matched thigh/shin. rig_map.py exists
so nothing downstream has to guess a bone name; only some consumers read
the roles it publishes.
Three new hard checks, none needing more than the vertices and the
sidecar:
character stands up in world space — against WORLD up, not against the
model's own proportions. "Is the spine the longest axis?" catches
nothing: a model rotated as a whole is internally consistent and
passes it comfortably.
character is a plausible size / height
every role the runtime needs is resolved
They separate the four good characters from the three broken ones on the
first run. Also fixed the posture measurement to read vertices rather than
object.bound_box, which is cached and still stale right after an import —
it reported a 1.75 m character as 1.18 m tall.
Recorded but not yet fixed: kiyoko faces backwards (facing is inferred by
two independent mechanisms and verified by neither), miku's grown hair
chains stretch under animation (generated chains are never validated
against the geometry they drive), and the mannequin's rifle hold does not
convince despite resolving correctly.
Co-Authored-By: Claude Opus 5 <[email protected]>
