security-game/docs/npc-model-sourcing.md

# NPC Model Sourcing

This page records the source evaluation and the active character plan. The
decision is [ADR-0017](adr/0017-quaternius-npc-base.md), which supersedes the
generator-first sourcing decision in [ADR-0015](adr/0015-npc-model-variety-sourcing.md).

## Active direction

**Quaternius Ultimate Modular Characters (CC0) is the primary NPC mesh and
animation source.** The project-owned procedural library remains the shipped
fallback until the Quaternius migration passes the silhouette and gear gates.

The migration keeps the runtime contract that Godot, gear and tests already
consume:

- one `npc_base` skinned mesh under the 13 required core bones (optional extras
  allowed);
- five tint slots: `skin`, `cloth`, `pants`, `accessory`, `hair`;
- front on Blender −Y / Godot +Z, feet grounded, height about 1.81 m;
- 24,000 triangles / 24,000 glTF vertices per character;
- gear stays at 1,500 triangles and props at 4,000;
- committed GLBs and maps only; no Quaternius, Blender or network dependency in
  CI, build or runtime.

### Stage 1 (default)

1. Import the researched Quaternius GLBs and choose a canonical base.
2. Map the 62 source joints to the 13-core contract and bake a proportion warp.
3. Skin the mesh, retarget Idle and Walk, and verify seated/arm-down poses.
4. Map the five slots, unwrap and bake 256² maps.
5. Fit the existing gear and render the silhouette gate.
6. Build the 12 variants, audit, and capture the 12 × 6 baseline.

The Quaternius 62-joint rig and its 24 animation clips are an **authoring
source**. They are not loaded at runtime.

### Stage 2 gate

The 62-joint T-pose source does not share the project's arm-down rest pose or
proportions. If the Stage 1 proportion warp cannot preserve the Quaternius
silhouette and deformation, stop the rollout and write a new ADR for adopting
the 62-joint rig at runtime. Do not ship a hybrid rig, a second gear offset
system or a silent `NpcAvatar` change.

## Research findings

The researched files are the three converted Quaternius outfits used by the
Ducz Character Creator: `Casual`, `Casual_Hoodie` and `Worker`. They are kept
locally in `tmp/npc-research/quaternius/` with the licence and mirror notes.

| File | SHA-256 | Structure |
| --- | --- | --- |
| `Casual.glb` | `bc2d84fba249ebaa0629cb9d133ad37234196e4b8004aa205a6397abed04e05c` | 4 meshes, 62 joints, 24 clips, 7 materials |
| `Casual_Hoodie.glb` | `f5b722199f7628b24550989af4230f65d5230727df9c326fd2b3e360effe5249` | 4 meshes, 62 joints, 24 clips, 7 materials |
| `Worker.glb` | `8d0f454336c2effc5c08f63a177af3a82d1a7af025ca9588b40e4c90c4703534` | 4 meshes, 62 joints, 24 clips, 11 materials |

Source: [Quaternius Ultimate Modular Characters](https://quaternius.com/packs/ultimatemodularcharacters.html)
and [Ultimate Modular Women](https://quaternius.com/packs/ultimatemodularwomen.html),
CC0 1.0. Download date: 2026-11-03 (via the Ducz Character Creator browser export).
The Ducz mirror is a browser builder over the same packs; it adds 21
outfits and a shared skeleton. The three full GLBs are the initial scope; the
21-part builder is a fallback for role coverage, not the default.

**Initial outfit scope (2026-11-05):** the three full GLBs (`Casual`,
`Casual_Hoodie`, `Worker`) are the canonical-base and silhouette-gate scope.
They cover only ~3 of the 12 roles (casual, hood, vest); the jacket, coat,
dress, responder (firefighter) and guard looks are not in the three GLBs, so
§4 roster coverage must pull those from the 21-part modular builder or author
new clothing. Do not start the modular builder until the canonical base passes
§3.

The first prototype measured 12,518 imported vertices, 3,199 after welding and
2,423 vertices / 4,654 triangles after a 0.75 decimate. Idle and Walk read well.
The source is a T-pose with a 62-joint realistic rig, roughly 0.96 m hip,
1.68 m arm span and 0.153 m shoulder offset, so a contract bake is required.

The 24,000 cap leaves room to stay much closer to the source LOD than the
prototype's 4,654 triangles. Do not decimate to the old 7,000-triangle target
before the silhouette gate.

## Quaternius GLB inventory (2026-11-05)

All three GLBs share one 62-joint rig and the same 24 animation clips; only the meshes and
materials differ. Each import also adds a 42-vert/80-tri `Icosphere` bone-display helper — ignore it.

### Meshes (verts / tris)

| GLB | Body | Feet | Head | Legs | Total |
| --- | --- | --- | --- | --- | --- |
| `Casual` | 5,338 / 2,654 | 1,082 / 538 | 5,122 / 2,526 | 1,426 / 706 | 12,968 / 6,424 |
| `Casual_Hoodie` | 6,132 / 3,048 | 1,024 / 512 | 3,836 / 1,888 | 1,526 / 758 | 12,518 / 6,206 |
| `Worker` | 6,074 / 3,018 | 928 / 464 | 1,862 / 936 | 1,670 / 822 | 10,534 / 5,240 |

### Joints (62)

- Spine: `Root, Hips, Torso, Body, Abdomen, Chest, Neck, Head` (8).
- Arms: `Shoulder.L/R, UpperArm.L/R, LowerArm.L/R, Wrist.L/R` (8) plus `PT.L/R` (2 pole targets).
- Fingers: `Thumb×3, Index×4, Middle×4, Ring×4, Pinky×4` × L/R (30).
- Legs: `UpperLeg.L/R, LowerLeg.L/R, Foot.L/R` (6).

### Animation clips (24)

`Idle, Idle_Neutral, Walk, Run, Run_Back, Run_Left, Run_Right, Wave, Interact, Death,
Gun_Shoot, Idle_Gun, Idle_Gun_Pointing, Idle_Gun_Shoot, Idle_Sword, Run_Shoot, Sword_Slash,
HitRecieve, HitRecieve_2, Kick_Left, Kick_Right, Punch_Left, Punch_Right, Roll`.

The retarget scope is Idle and Walk; combat/gun/sword clips are discarded (see §2).

### Material → slot map

The five project slots (`skin`, `cloth`, `pants`, `accessory`, `hair`) are assigned by mesh
region first, then material — the same material name can mean `cloth` on the body and
`accessory` on the feet.

| Material | Where | Project slot |
| --- | --- | --- |
| `Skin` | all meshes | `skin` |
| `Hair_Blond`, `Hair_Brown`, `Hair`, `Brown` (head), `Eyebrows`, `Moustache` | Head | `hair` |
| `Eye` | Head | `accessory` |
| `Worker_Yellow` | Worker body (vest stripe) + head (helmet) | `cloth` / `accessory` |
| `White`, `Grey`, `Purple`, `Black` | Body / Feet | `cloth` (body) / `accessory` (feet) |
| `Orange`, `LightBlue`, `LightBrown`, `Brown`, `Brown2` | Legs | `pants` |
| `Worker_Vest` | Worker body | `cloth` |

### Canonical base (built 2026-11-05)

`tmp/npc-research/quaternius_base.glb` is the welded, triangulated, grounded, animation-free
canonical base built from `Casual_Hoodie.glb` (the most detailed body) by
`tmp/npc-research/build_quaternius_base.py`:

- one `npc_base` mesh — 3,199 welded verts / 6,206 tris (Body + Feet + Head + Legs joined);
- 62 joints, skinned (no unskinned faces);
- height 1.81 m, feet at y 0, front on Godot +Z / Blender −Y (T-pose rest);
- no animation clips; `inspect` clean (no issues).

This is the §2 contract-bake input: the 62-joint rig is authoring-only and is mapped to the
13-core contract next, not shipped as-is.

## 62-joint → 13-core joint map (2026-11-05)

The Quaternius hierarchy (measured from `quaternius_base.glb`):

- `Root → Body → Hips → Abdomen → Torso → Chest → Neck → Head` (spine);
- `Chest → Shoulder.L/R → UpperArm.L/R → LowerArm.L/R → Wrist.L/R → fingers` (arms);
- `Body → UpperLeg.L/R → LowerLeg.L/R` and `Root → Foot.L/R` (legs — the foot is a separate
  child of Root, not of LowerLeg);
- `Root → PT.L/R` (IK pole targets, no deforming weights).

The contract is 14 bones (13 core + `Hips` root): `Hips, Spine, Neck, Head, Shoulder.L/R,
Elbow.L/R, Hand.L/R, Hip.L/R, Knee.L/R`. The map:

| Contract bone | Quaternius source | Notes |
| --- | --- | --- |
| `Hips` | `Hips` | `Root` + `Body` collapse into `Hips` |
| `Spine` | `Abdomen`, `Torso`, `Chest` | three collapse into one |
| `Neck` | `Neck` | |
| `Head` | `Head` | |
| `Shoulder.L/R` | `UpperArm.L/R` | the collar `Shoulder.L/R` collapses into `Spine` |
| `Elbow.L/R` | `LowerArm.L/R` | |
| `Hand.L/R` | `Wrist.L/R` | |
| `Hip.L/R` | `UpperLeg.L/R` | |
| `Knee.L/R` | `LowerLeg.L/R` | |

Optional extras (allowed by the contract; kept if they survive within 24,000 vertices):

- the 30 finger bones (`Thumb×3, Index×4, Middle×4, Ring×4, Pinky×4` × L/R) → optional finger
  bones;
- `Foot.L/R` → optional toe bones.

Dropped (never shipped): `PT.L/R` (pole targets carry no deforming weights), and the
`Root`/`Body`/collar-`Shoulder` collapse bones above.

## Rest-pose and proportion-warp measurement (2026-11-05)

The rest-pose bake (T-pose → arm-down) works: rotate the `UpperArm.L/R` pose bones −90° around
their local X, apply the Armature modifier to bake the deformation, then `armature_apply` to bake
it as the new rest pose (see `tmp/npc-research/warp_full.py`). The mesh deforms cleanly to the
arm-down pose (deformed bounds x ±0.221 vs the T-pose ±0.811).

The proportion warp to the contract positions is measured and it **distorts the silhouette**:

| Joint | Quaternius | Contract | Delta |
| --- | --- | --- | --- |
| Hips height | 0.869 | 0.62 | −0.249 (lower hip) |
| Head top | 1.614 | 1.82 | +0.206 (raise head) |
| Shoulder x | 0.148 | 0.27 | +0.122 (widen) |
| Arm (shoulder→wrist) | 0.402 | 0.60 | ×1.49 |
| Arm (shoulder→hand tip) | 0.429 | 0.70 | ×1.63 |
| Leg (hip→ankle) | 0.835 | 0.62 | ×0.74 |
| Torso (hip→head) | 0.745 | 1.20 | ×1.61 |

The vision judge reads the warped mesh as: paddle/claw hands (the 1.63× arm stretch blows the
hand out), forearms lost into the torso, stretched shins, and "long legs + short torso". The arm
must either stay short (a "shortened arm" vs the contract hand) or stretch 1.63× (a distorted
deltoid + hand) — both are the gate's rejection conditions.

**Finding:** the Stage 1 proportion warp cannot preserve the Quaternius silhouette at the
contract proportions; the gate fails and Stage 2 (a 62-joint runtime ADR) is indicated. Do not
start the 12-variant rebuild on the warped base.

[ADR-0018](adr/0018-quaternius-stage2-runtime-rig.md) records the Stage 2 decision (accepted
2026-11-05, owner chose option 2): adopt the **Quaternius 62-joint rig at runtime**, keep the
mesh at source LOD, re-derive gear attach points from the Quaternius skeleton, and use the
Quaternius Idle/Walk clips directly (no retarget).

## Pilot bake and shipped state (2026-11-05)

`npc_casual` is the first Quaternius-derived character. The reproducible pipeline lives in
`tmp/npc-research/` (local tooling, not shipped) and has two steps:

1. `build_base_minimal.py` — import `quaternius/Casual_Hoodie.glb`, join the four skinned meshes
   **without welding**, rename the upstream materials to the project tint slots, Smart-UV-unwrap
   and repack, export `quaternius_tpose.glb`.
2. `bake_armdown_v5.py` — pose `UpperArm.L/R` −90° local X, read the posed matrices, apply the
   Armature modifier, **reset the pose to identity**, set the rest matrices, re-add the modifier,
   export `quaternius_base.glb` and save `assets/models/blender_src/npc_casual.blend` for the AO
   bake.

Then `tools/bake_ao.py --only npc_casual` and a copy of the GLB to
`assets/models/blender/npc/npc_casual.glb`.

| Measurement | npc_casual (Quaternius) | procedural library |
| --- | --- | --- |
| Triangles | 6,206 | 4,812–6,046 |
| glTF vertices | 12,988 | 4,908–5,785 |
| Bones | 62 | 13 |
| Head height / body height | 0.134 | 0.16–0.22 (stylized band) |
| Shoulder width | 0.201 m head width, `fit` OK | `fit` OK |
| Texel density (256² maps) | 73–74 px/m | 75–96 px/m |
| Materials | `skin`, `cloth`, `pants`, `hair`, `accessory` + fixed `Eye`, `Eyebrows` | five slots + fixed detail |

Two source quirks shaped the bake:

- the upstream UV map is degenerate (every loop at 0,0) and its materials are flat colours, so the
  AO/texture bake must follow a real unwrap or it silently writes a black map;
- the upstream materials are named `Skin`/`Purple`/`LightBlue`/`White`/`Hair`, so the five-slot
  contract is applied as a rename, not a re-author.

The face/silhouette gate that chose the full swap is recorded in the follow-up decision of
[ADR-0018](adr/0018-quaternius-stage2-runtime-rig.md); its comparison sheets were retired with the
review pages.

## Shipped roster (0.9.9, owner chose the full swap)

Every public character name is baked from one of the three CC0 sources. The build is
`tools/blender_assets.py build` (default `--source quaternius`); the sources live in
`assets/models/blender_src/quaternius/` and the geometry pipeline is two passes:

1. `_quaternius_tpose_glb()` — import, drop the Icosphere helper, join **without welding**,
   repoint the upstream materials onto the five tint slots, Smart-UV-unwrap + repack, export an
   intermediate T-pose GLB. The round trip also normalises the mirrored upstream bone rolls,
   which is what makes the next pass symmetric.
2. `_bake_quaternius_rest()` — pose `UpperArm.L/R` -90° local X, read the posed matrices, apply
   the Armature modifier, reset the pose, write the rest matrices, re-add the modifier, export
   with `export_apply=False`.

Then `tools/bake_ao.py --only <name>`.

| Character | Source | Tris | Material slots |
| --- | --- | --- | --- |
| `npc_casual` | hoodie | 6,206 | skin, cloth, pants, hair, accessory + Eye, Eyebrows |
| `npc_jacket` | casual | 6,424 | five slots + eyes/brows |
| `npc_coat` | hoodie | 6,206 | five slots + eyes/brows |
| `npc_vest` | worker | 5,240 | five slots + hivis vest/hat, eyes, moustache |
| `npc_dress` | casual | 6,424 | five slots + eyes/brows |
| `npc_hoodie` | hoodie | 6,206 | five slots + eyes/brows |
| `npc_firefighter` | worker (vest + hat dropped) | 4,458 | five slots + eyes, moustache |
| `npc_guard` | worker (vest + hat dropped) | 4,458 | five slots + eyes, moustache |
| `npc_crowd_a` | casual | 6,424 | five slots + eyes/brows |
| `npc_crowd_b` | casual | 6,424 | five slots + eyes/brows |
| `npc_crowd_c` | hoodie | 6,206 | five slots + eyes/brows |
| `npc_crowd_d` | worker (vest + hat dropped) | 4,458 | five slots + eyes, moustache |

Source slot maps (`QUATERNIUS_SOURCES`): the `casual` tee is `Skin`/`White`/`Orange`/`Grey`/
`Hair_Blond`; the hoodie is `Skin`/`Purple`/`LightBlue`/`Hair`/`White`; the worker is `Skin`/
`LightBrown`/`Brown`+`Brown2`/`Grey`+`Black`/`Eyebrows`. Everything not in the map keeps its
authored colour (eyes, brows, moustache, hivis vest and hard hat), so the contract still holds if
upstream adds a material — it shows up as an extra fixed-colour slot instead of vanishing.

Head gear is authored for this head: `HEAD_GEAR_SCALE = 0.64` and `HEAD_GEAR_LIFT = 0.07` map the
0.315 m procedural head onto the 0.201–0.214 m Quaternius head. The procedural fallback therefore
wears slightly small hats.

## Modular outfit intake (2026-11-06)

The owner downloaded the *Ultimate Modular Men* pack once (CC0 1.0, 54.5 MB zip, 15 outfit families
plus weapons and a horse) into the gitignored `tmp/quaternius-intake/`. The pack ships FBX, not GLB,
so the intake composes each family into a single skinned base:

    python3 tools/quaternius_parts.py make-base \
      --family "tmp/quaternius-intake/Ultimate Modular Men- Feb 2022/Separate Skeletal Meshes and Animations/Suit" \
      --out assets/models/blender_src/quaternius/Suit.glb

What `make-base` has to undo, and why it is not a straight import:

1. each of the four FBX files carries its own copy of the armature — one is kept and the meshes are
   repointed at it, otherwise `join` leaves three meshes bound to deleted armatures;
2. the FBX rig adds zero-length `_end` leaf bones and a `neutral_bone` root; Godot's importer fails
   the exported GLB with them (`resource_format_binary` error), so they are stripped back to the
   accepted 62 joints;
3. the object transforms are baked before export, or the glTF node transforms change the rest pose
   on import and the character renders with a giant head;
4. the pack reuses one fabric material for jacket and trousers, so the leg meshes get their own
   `*_legs` copies that the slot map sends to `pants`;
5. imported parts share seams, which leaves zero-area triangles the audit rejects.

The pack itself is never committed. Only the composed bases are, with their SHA-256 here and in
`CREDITS.md`.

| Base | Source family | SHA-256 | Used by |
| --- | --- | --- | --- |
| `Suit.glb` | Suit | `674f2a63…` | `npc_coat` |

## Contract mismatch

The expensive part is the rig and proportions, not the mesh. The source has a
T-pose and a realistic skeleton; the runtime expects an arm-down 13-core rig,
fixed gear attach points and the existing pose composition. The Stage 1 bake
must therefore:

- rotate the arms down and match the contract wrist positions;
- warp the hips, knees, shoulders and head without collapsing the deltoid,
  shortening the arms or changing the silhouette;
- keep one skinned `npc_base` mesh and the five slots;
- verify gear against the new shoulder, hip and head positions.

If those constraints distort the model, Stage 2 is the correct next decision,
not a local workaround.

## Licence and provenance

- CC0 preferred. CC-BY is allowed only with attribution in
  [`CREDITS.md`](../CREDITS.md).
- No service asset whose terms restrict redistribution may be shipped.
- Keep the source URL, author, licence, download date and SHA-256 in this page
  and in `CREDITS.md`.
- Research files and generated previews stay in `tmp/` (gitignored). Only final
  audited assets and committed review sheets enter the repository.
- Quaternius models and animations are CC0; the existing credits entry already
  names Quaternius. Keep it accurate if the shipped source set changes.

## Closed tracks

The MakeHuman/MPFB body pipeline is closed for the NPC base. The accepted
MakeHuman head and the procedural `npc_base` remain tested fallbacks until the
Quaternius rollout is complete. Their research scripts and renders were removed
from `tmp/` after the pivot; the measurements and decisions remain in
[`DONE.md`](../DONE.md), [`MEMORY.md`](../MEMORY.md) and the review docs.

## Related documents

- [ADR-0017: Quaternius NPC base](adr/0017-quaternius-npc-base.md)
- [ADR-0016: 24,000-triangle character budget](adr/0016-npc-character-budget-24k.md)
- [Blender asset contract](architecture.md#character-and-gear-asset-contract)
- [`3d-model-review.md`](3d-model-review.md)
- [`asset-tooling.md`](asset-tooling.md)