Nicholas ButzkeandClaude Opus 5
700d0925d7
momo's idle plays with her arms overhead and her waist pinched, and every assertion in the suite passes on her. The first suspicion was the retarget's rest-relative delta: it applies "what the clip does to the LIBRARY's rest" to THIS rig's rest, which quietly assumes the two rests are alike. rest_pose_check.gd tests that, and disproves it — miku's arms rest 41° off the library's and taila's 32°, and both animate correctly. The delta retarget handles a rest-pose difference, which is what it is for. Recorded in the reference so nobody spends that hour again. Writing the tool reproduced this project's own recurring mistake in miniature. Measuring "the direction from a bone to its first child" reported kiyoko's and aria's legs 71° off the library — because a thigh's first child is as likely to be a skirt bone as a shin, and it was measuring the hang of a skirt panel. Pointing it at the next limb BY ROLE dropped both to 1°. What momo actually has: `Root_001` through `Root_007` are in her driven_bones, and they are her HAIR roots — Hair_A is dominated by Root_001_001, Root_007 and Root_005. The animation is keying bones the spring solver is supposed to own, which is non-negotiable #2 broken by the role resolver rather than by a clip. The surface table corroborates it: her hair surfaces report 1.8% and 9.4% chain share, because most of their vertices belong to bones in no chain at all. Not fixed here. `Root_00N` matches no COSMETIC stem, and adding "root" to the stems would cost a rig whose actual root is called `Root` its hips. The structural fix is that a bone whose geometry is dominated by a mesh classified `hair` is a hair bone whatever it is called — which the surface table makes answerable at build time, and did not when momo was imported. It needs a Blender re-run and re-verification of all six characters. Co-Authored-By: Claude Opus 5 <[email protected]>
152 lines
7.7 KiB
Markdown
152 lines
7.7 KiB
Markdown
# Verification — and the trap that invalidated all of it
|
||
|
||
## READ THIS FIRST
|
||
|
||
**Godot restores every bone's local pose after the `SkeletonModifier3D` pass.**
|
||
|
||
So calling `force_update_all_bone_transforms()` and reading
|
||
`get_bone_global_pose()` from a `SceneTree` script, from `_process`, or anywhere
|
||
outside that pass recomputes the globals from the **animation alone**. The
|
||
shooter pose layer and the cloth solver are simply not in what you measure.
|
||
|
||
`debug/cloth_clip_check.gd` did exactly this. It reported the same ~95 mm of
|
||
leg-inside-skirt with collision fully enabled **and with the collision call
|
||
commented out**. Every number ever taken from that tool before 2026-07-26 is
|
||
void, and several rounds of "tuning did nothing" in the history were reading a
|
||
pose the solver never touched.
|
||
|
||
**To measure a pose layer, add your own `SkeletonModifier3D` as a child of the
|
||
`Skeleton3D` AFTER the one you care about, and snapshot inside its
|
||
`_process_modification()`.** The `PoseProbe` class in `cloth_clip_check.gd` and
|
||
`travel_dir_check.gd` is the pattern.
|
||
|
||
Two related traps:
|
||
|
||
- **Headless runs uncapped**, so the engine delta is sub-millisecond and anything
|
||
integrated barely moves. Set `SpringBones.fixed_delta = 1.0/60.0`.
|
||
- **A single frame of a locomotion clip measures the clip.** A run cycle twists
|
||
the torso against the hips by tens of degrees twice per stride, swamping
|
||
anything a pose layer does. Average over a stride.
|
||
|
||
## The tools
|
||
|
||
| Tool | Measures | Good |
|
||
|---|---|---|
|
||
| `spawn_smoke_test.gd` | spawn, skins, anim tree, camera, state cycling | 29 OK, 0 failures |
|
||
| `cloth_clip_check.gd` | leg-inside-cloth per movement state, per vertex | idle < 25 mm |
|
||
| `cloth_settle_check.gd` | deg/frame at a dead idle, contacts/frame | skirt < 0.1, hair < 0.01 |
|
||
| `cloth_perf_check.gd` | ms per character per frame | ~2.6 ms |
|
||
| `cloth_allow_check.gd` | how much of each limb the rest-clearance cap makes the solver blind to | 17–35 mm on Taila |
|
||
| `cloth_stretch_check.gd` | mesh tearing between panels | no 3× edges |
|
||
| `travel_dir_check.gd` | stride direction vs. travel direction | < 10° except a capped sidestep |
|
||
| `limb_deform_check.gd` | joint collapse | knee ~0.99 |
|
||
| `verify_character.py` | meshes, bones, weights of a SOURCE model | several meshes, cloth bones present |
|
||
| `surface_class_check.gd` | every surface resolves from the sidecar, not the fallback | 0 fallbacks on all six skins |
|
||
| `character_picker_check.gd` | the escape-menu roster: skeleton, clips, surfaces, and that the pose MOVES | 0 failures |
|
||
| `rig_anchor_check.gd` | a grip anchor physically moves the weapon, and clears | 0 failures |
|
||
| `anim_capture.gd` / `orbit_capture.gd` | renders, for looking | — |
|
||
| `roster_capture.gd` | one photo of every character, from the picker | — |
|
||
| `ui_capture.gd` | one photo of every menu screen | — |
|
||
| `rest_pose_check.gd` | each rig's bind-pose limb directions vs. the library's | see below |
|
||
|
||
## What `rest_pose_check` actually established
|
||
|
||
It was written to test a suspicion — that the rest-relative retarget silently
|
||
assumes both rigs rest alike — and it disproved it. Miku's arms rest **41°** off
|
||
the animation library's and Taila's **32°**, and both animate correctly. The
|
||
delta retarget handles a rest-pose difference, which is what it is for. Do not
|
||
go looking there again.
|
||
|
||
It also demonstrates the measurement trap in miniature. Written as "the direction
|
||
from a bone to its FIRST CHILD", it reported kiyoko's and aria's legs 71° off —
|
||
because a thigh's first child is as likely to be a skirt bone as a shin, and it
|
||
was measuring the hang of a skirt panel. Pointing it at the next limb BY ROLE
|
||
dropped both to 1°. The same rule as everywhere else in this pipeline: resolve
|
||
roles, never take whatever the rig happens to hand you.
|
||
|
||
## Assert the consequence, not the plumbing
|
||
|
||
Three of these exist because the obvious check passes on a broken system.
|
||
|
||
- `character_picker_check` asserts the skeleton's pose CHANGES over a dozen
|
||
frames. Asking the model which clip it is playing does not work: that is a
|
||
variable the class sets on itself, and it reads `"Idle"` just as happily when
|
||
the animation tree is not ticking at all.
|
||
- `rig_anchor_check` asserts the weapon MOVES by the offset asked for. An anchor
|
||
system is easy to build so that the sliders move, the file saves and the JSON
|
||
round-trips while the gun does not budge — the value read into a variable
|
||
nobody consumed. It measures in the attachment's frame, not the world's:
|
||
the attachment tracks a bone on an animating skeleton, so a world-space delta
|
||
is mostly the idle animation.
|
||
- `surface_class_check` FAILS on a surface that falls through to the heuristic
|
||
instead of resolving from the table. A model whose names stopped matching still
|
||
renders — the fallback catches it — and quietly loses its per-class art
|
||
direction. Nothing else would report that.
|
||
|
||
And four of the last five real defects came from LOOKING, not from asserting:
|
||
a preview showing the back of the character's head, a turntable that carried on
|
||
from the previous character, an unstyled list, and momo's idle pose. Every one
|
||
passed every assertion. Run `roster_capture` and `ui_capture` and open the PNGs.
|
||
|
||
Run them:
|
||
|
||
```bash
|
||
godot --headless --path . -s res://debug/<tool>.gd
|
||
godot --headless --path . -s res://debug/<tool>.gd -- res://assets/characters/skins/<name>.glb
|
||
```
|
||
|
||
Scripts run with `-s` MUST extend `SceneTree`. A `Node` script never quits and
|
||
hangs forever.
|
||
|
||
## Measure the right quantity
|
||
|
||
`cloth_clip_check.gd` used to report "how much CLOSER the leg got than the artist
|
||
modelled it". A hem 200 mm clear of a shin legitimately comes 180 mm closer when
|
||
the leg kicks out in a slide, and counting that as a failure buried the real
|
||
clipping under motion the character is supposed to have. It now reports how far
|
||
INSIDE a capsule a cloth vertex is, over and above however far inside it was
|
||
modelled — only cloth actually within the capsule can be showing a leg through.
|
||
|
||
It also applies the collider's `from` offset, so it tests the same band of thigh
|
||
the solver is defending. Measuring the full bone tests the hip cap the solver
|
||
deliberately excludes and reports it as clipping no tuning can fix.
|
||
|
||
## What the suite still does not check
|
||
|
||
It verifies that a character is WELL-FORMED, not that it is CORRECT. Those are
|
||
different properties, and only the first was ever asserted — which is how four
|
||
characters shipped "All checks passed" while lying on their backs, seven times
|
||
too large, facing backwards, or unable to hold a gun. See `failure-modes.md`.
|
||
|
||
`posture` and `bone roles reachable at runtime` are now hard checks. Still
|
||
missing, and worth adding when a source next exposes them: facing measured on the
|
||
OUTPUT, and per-vertex validation that a generated cloth chain actually tracks
|
||
the geometry it was given.
|
||
|
||
## Diagnosing "the solver isn't working"
|
||
|
||
In order:
|
||
|
||
1. **Is the measurement inside the modifier pass?** (Above. Do this first.)
|
||
2. **Does the solver SEE the contact?** `debug_hit_report()` — bone → deepest
|
||
overlap it found. If ~0 while the mesh is deep inside a leg, the collision
|
||
hull does not cover the geometry that is clipping.
|
||
3. **Does it CONVERGE?** `debug_residual_report()` — overlap left after the
|
||
relaxation. Seen 93 mm, left 95 mm is a standing fight, not slow convergence;
|
||
quadrupling the iterations will buy nothing. Find what is pulling back.
|
||
4. **Only then, tune.**
|
||
|
||
That order was learned the hard way: the drape, the bend limits, the backstop,
|
||
the iteration count and the hull sampling were each suspected and tested, and
|
||
the answer was in step 1.
|
||
|
||
## Also run
|
||
|
||
```bash
|
||
godot --headless --path . -s res://movement/tests/run_fsm_tests.gd # 11 tests
|
||
godot --headless --path . --check-only --script res://<file>.gd # syntax
|
||
```
|
||
|
||
Autoload identifiers report false "not found" errors under `--check-only` —
|
||
ignore those.
|