zwitschi
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Group the top-level docs into docs/project, docs/design, docs/assets and docs/process, each with its own README index. Delete the superseded docs/screens/head-review page and sheets. Rewrite every markdown link, absolute docs path and tool/test reference to the new locations, fix the pre-existing broken anchors and remove the dead Joke Shop photo-board link. check_docs OK, Python tooling 167/167.
90 lines
4.4 KiB
Markdown
90 lines
4.4 KiB
Markdown
# ADR-0015: NPC model variety sourcing
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- **Status:** Superseded by [ADR-0017](0017-quaternius-npc-base.md) (2026-11-05)
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- **Date:** 2026-11-03
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## Superseded
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ADR-0017 replaces the generator-first decision below: Quaternius is now the
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primary NPC base. The evaluation, licence rules and consequences remain as the
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record of the 2026-11-03 decision.
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## Context
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The library has eight skinned characters, and role/seed selection reuses them
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across the three venues. Crowds therefore repeat the same faces, builds and
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outfits. The existing contract is strict: `npc_base` mesh node, 13 named bones at
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fixed rest positions, five tint slots, front on Blender −Y and an 8,000
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triangle/vertex budget.
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A review compared free/open-source sources against that contract. Quaternius
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Ultimate Modular (CC0), Kenney Blocky Characters (CC0), Khronos CesiumMan and
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RiggedFigure (CC BY 4.0) and the MakeHuman base mesh (CC0) were imported and
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measured. None was a drop-in; the full results are in
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[`docs/assets/npc-model-sourcing.md`](../assets/npc-model-sourcing.md).
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## Decision
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1. **Ship only CC0, or CC BY with recorded attribution.** No service asset whose
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terms restrict redistribution may be used.
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2. **Extend the project-owned procedural generator as the primary path** for
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shipped NPC variety. The first target is four crowd-variety looks, bringing
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the library to twelve characters.
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3. **Keep Quaternius as a reviewed reference/prototype, not a shipped base.** A
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contract retarget is a no-go because the source is a T-pose 62-bone realistic
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rig with substantially different proportions from the arm-down 13-bone
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contract. A future external-rig path would need its own ADR covering its
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skeleton, animation source and per-model gear offsets.
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4. **MakeHuman is deferred to a separate local development pipeline.** Its CC0
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base mesh can be decimated into budget, but it needs retopology, a custom rig
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and project-owned clothing before it is usable. It must not become a CI or
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build dependency.
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5. **Commit research previews with attribution.** CC-BY preview images are
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development-only and are not bundled with the game or its release packages.
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## Consequences
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### Positive
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- The shipped library keeps one art direction, one skeleton and one audit gate.
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- Crowd variety lands without a new runtime dependency or a second animation
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system.
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- The licence position is simple: project-owned assets plus explicit CC-BY
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attribution where a preview or future asset requires it.
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- The Quaternius evaluation removes a tempting but high-risk retarget from the
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critical path.
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### Negative
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- Procedural variation is still limited by the existing face and clothing
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vocabulary; four variants do not provide full age/body diversity.
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- Quaternius' animation set remains unused unless a second rig path is approved.
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- MakeHuman body-shape diversity is postponed.
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- External previews add a small documentation footprint that must stay out of
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release packages.
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## Alternatives considered
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- **Retarget Quaternius onto the `npc_base` contract.** Rejected for now:
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welding brings the geometry inside budget, but the rest pose and body
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proportions differ enough that a contract rebuild would either distort the
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model or require a full proportion warp.
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- **Use Quaternius' own rig and animations directly.** Deferred: attractive
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animation quality, but it adds a second skeleton/animation path and per-model
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gear offsets to `NpcAvatar`.
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- **Use MakeHuman as the primary body source.** Rejected for this milestone: high
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polygon count, no rig in the base mesh and a separate authoring dependency.
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- **Use Mixamo or Ready Player Me.** Rejected: service terms are not a simple
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free/open-source redistribution basis for shipped meshes.
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## Amendment 2026-11-04
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- The character budget is raised to **16,000 triangles / 16,000 glTF vertices** per character.
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The required 13 core bones remain; optional extra bones (fingers, face, toes) are allowed if
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they do not move the core rest positions. The low-poly fallback remains the fallback, not a
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second contract.
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- MakeHuman is now an active local development pipeline (body retarget plus project-owned
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head/hands), while the procedural library remains the shipped path and CI fallback.
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- Blender MCP is optional interactive tooling only; it is not a build, CI, test or runtime
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dependency. Setup is in [`docs/assets/asset-tooling.md#optional-interactive-blender-mcp`](../assets/asset-tooling.md#optional-interactive-blender-mcp).
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