# NPC Model Sourcing

This page records the source evaluation behind [ADR-0015](adr/0015-npc-model-variety-sourcing.md).
The shipped path is the project-owned Blender/procedural library; external sources
remain references or local prototypes unless a later ADR accepts them.

## Evaluation

The library needs variety beyond the original eight silhouettes while preserving
the `npc_base` contract: mesh node, 13 required core bones (optional extras
allowed), five tint slots, −Y/+Z front, grounded feet and the 16,000/16,000
character budget.

| Source | Licence | Result |
| --- | --- | --- |
| Quaternius Ultimate Modular | CC0 | Good silhouette/decimation material, but a 62-bone T-pose realistic rig and different proportions; not a drop-in. Kept as a reference/prototype. |
| Kenney Blocky Characters | CC0 | No matching rig; style is much blockier than the project look. |
| Khronos CesiumMan / RiggedFigure | CC BY 4.0 | Different bone names/rest pose and no five-slot materials; not a drop-in. |
| MakeHuman / MPFB base | CC0 | Useful body-shape base, but requires retopology, a custom rig, clothing and part integration. Active local pipeline, not the shipped path. |

The contract mismatch is the expensive part, not decimation: retargeting a
different rig or rebuilding slots/weights can distort the body and invalidate
gear placement. Any future second-rig path needs its own ADR and animation/gear
offsets.

## Decision and outcome

- Extend the project-owned procedural generator as the primary shipped path
  (12-character library, crowd variants, role pools).
- Keep Quaternius as a studied reference, not a shipped base.
- MakeHuman is a local development pipeline for body-shape diversity; it must
  consume the same head/hand parts as the procedural library and never become a
  CI/build dependency.
- Record CC0/CC-BY provenance; CC-BY previews require attribution in
  [`CREDITS.md`](../CREDITS.md).

## MakeHuman prototype notes

The local prototype (`tmp/npc-research/`, never committed) scaled the base to
1.82 m, grounded it, triangulated/decimated it and retargeted it to the 13-core
armature. The first retarget measured **6,444 / 16,000 tris and**
**7,726 / 16,000 verts**, 14 bones, skinned, arm-down, five slots. It exposed
the expected issues: a 1.63× arm-scale warp at the deltoid/shoulder, blocky
decimated hands, rough slot boundaries and a head/neck shadow gap. The later
project head/hands swap reduced this to **6,407 / 16,000 tris and**
**6,651 / 16,000 verts**, but manual shoulder/neck retopology and part cleanup
remain before it can be considered shippable.

A standalone MakeHuman head is recorded in
[`makehuman-head-review.md`](makehuman-head-review.md). The owner accepted the basic
human head on 2026-11-04; the assembled path (`build_character(head="mh")`) adds a
skull-conforming hair cap and hides the scalp under it. The 12 shipped GLBs still use
the procedural head until the hair/body review and rollout in [`TODO.md`](../TODO.md).
The MakeHuman body should reuse the approved local head/hand parts rather than forking
a second face implementation.

The current local MPFB full-body prototype (`tmp/npc-research/build_mpfb_npc.py`) assembles the
accepted head on an MPFB 2.0.18 body at **15,213 / 16,000 tris**, 1.810 m, 14 bones and 10
materials, with project hands, bevelled shoe shells, pant cuffs, accessory cuffs and flat slot
colours. It is a review candidate, not a shipped asset. The neck is a radial cut of the decimated
column bridged by a four-ring, 20-segment lathe (lower rings painted cloth, reading as a crew neck);
the ankles are hidden by 0.12 m shoe shells and 0.08 m pant cuffs, and a light smoothing pass
softens the closed thigh/hip region. Remaining polish: a V-shaped shirt hem at the crotch, a
skin-tight shirt and angular thigh facets; a proper shirt shell is the fix. A torus collar, cloth
cylinder collar, skin neck-blend sphere, destructive vertex-smoothing pass and untucked shirt-hem
band were tried and removed because they read as a brace, shelf, donut or hanging flap, or tore a
hole at the collar. The production integration decision (bake a committed
source GLB or keep the procedural body) and the owner review are tracked in `TODO.md`; MPFB itself
must not become a CI/build dependency.

## Provenance rules

- CC0 preferred; CC-BY only with attribution in `CREDITS.md`; no service asset
  whose terms restrict redistribution.
- Downloaded research and generated previews stay in `tmp/`/gitignored folders;
  only final audited assets and committed review sheets enter the repository.
- Record source URL, licence, author, date and what decision the reference
  informed. Never treat a generated concept as licensed map/model data.

Measurements, visual decisions and accepted limits are in
[`3d-model-review.md`](3d-model-review.md) and
[`npc-visual-review.md`](npc-visual-review.md). Commands are in
[`asset-tooling.md`](asset-tooling.md).