feat(groom): author and look-develop the rigged human bob

.gitignore

@@ -261,4 +261,6 @@ scripts/steam/generated/
 /OloEditor/assets/tests/visual/TerrainSnow_*
 /OloEditor/assets/tests/visual/GroomSceneShadow_GL_Forward_VsmNearOccluder*
 /OloEditor/assets/tests/visual/VirtualShadowMap_Contact*
+# Native human-hair authoring matrix (#1593); curate review images in docs.
+/OloEditor/assets/tests/visual/HumanHairNative_*.png
 /.v-build/

OloEditor/SandboxProject/Assets/Grooms/HumanSource/Human.recipe.json

@@ -0,0 +1,34 @@
+{
+  "recipe": 1593,
+  "strands": 123974,
+  "pointsPerStrand": 32,
+  "tools": {
+    "python": "3.13.7",
+    "blender": "5.2.2 LTS",
+    "numpy": "2.5.4",
+    "scipy": "1.18.1"
+  },
+  "locks": 711,
+  "guides": 1149,
+  "scalpClearance": {
+    "controlsProjected": 1031642,
+    "maxCorrection": 0.010025072171657485,
+    "regrowthStrands": 17512
+  },
+  "generatorSha256": "2fb10e4d7970157cc1eef51867f2b986134315eed8b340fa81b6a6563731f17e",
+  "meshSha256": "d7fd26171110629e88965057ca597cab11f79fe0946bbc0a4bc3e2d6fcf6ca00",
+  "bufferSha256": {
+    "HeadRigged.bin": "fd5a2d5bdcd18e6c2f873dd9e8e7e93bd8dcd21e2b4bb350c5b47b5e1da882a3"
+  },
+  "curveSha256": "fd77e4daa29d524b99eafe55d91e1fcf7f3bd2eb97478aa9fc9edd733b524477",
+  "boundsMin": [
+    -0.11272127195649533,
+    0.17420390023914684,
+    -0.13635755850781456
+  ],
+  "boundsMax": [
+    0.10464214479973351,
+    0.43598300218582153,
+    0.11750753418165019
+  ]
+}

OloEditor/SandboxProject/Assets/Grooms/HumanSource/README.md

@@ -0,0 +1,101 @@
+# Author the head's hair from the rigged scan
+
+`build_human_hair.py` authors a centre-parted, jaw-length dark-brown bob for
+`assets/models/InfiniteScanHead/HeadRigged.gltf` (#1593). The scan, skin texture,
+rig, LookAround animation and measured thickness map are read only.
+
+The visual reference is the Alberta Ferretti SS21 runway photograph in
+[Marie Claire's centre-part gallery](https://www.marieclaire.it/bellezza/capelli/g34409654/tagli-capelli-riga-in-mezzo/)
+([photograph](https://hips.hearstapps.com/hmg-prod/images/riga-centrale-capelli-ss-2021-alberta-ferretti-1603091441.jpg),
+consulted 2026-10-11). It provides a narrow scalp part, swept forehead locks,
+continuous scalp-to-length flow, a dark body with localized uncoloured highlights,
+and separated tips above the shoulders. The photograph is a reference only;
+it is not redistributed, traced or used as a texture. The groom is authored here.
+
+## Reproduce and cook
+
+Use Python 3.13 with Blender's `bpy==5.2.2`, `numpy==2.5.4` and `scipy==1.18.1`
+in an isolated environment. The `bpy` wheel includes Alembic and runs headlessly.
+From the repository root:
+
+```powershell
+python OloEditor/SandboxProject/Assets/Grooms/HumanSource/build_human_hair.py `
+  --out <scratch>/Human.abc --blend <scratch>/Human.blend
+$env:OLO_HUMAN_HAIR_ABC = '<absolute scratch>/Human.abc'
+$env:OLO_HUMAN_HAIR_EXPORT = '<absolute scratch>/cooked'
+build-cached-core/OloEngine/tests/Release/OloEngine-Tests.exe `
+  --gtest_filter=GroomAnimalsAcceptanceEvidenceTest.ExportsHumanHairPair
+```
+
+Build through `.claude/skills/run-oloengine/build-lock.ps1` before cooking.
+The engine's Alembic importer, groom cooker and binding builder produce the pair.
+The cook exports only `Human.ologroom` and `Human.ologroombinding` to scratch;
+install both in `Assets/Grooms/Animals` after inspection. Existing registry handles
+are preserved. Regenerate Acceptance with `scripts/perf/generate-acceptance-scene.py`
+after updating HumanCoat's settings in GroomAnimals. Set its render budget from
+the recipe's strand count and disable extra length jitter: variation and locks
+are already authored into the source curves.
+
+Alembic and `.blend` are generated authoring outputs, kept outside the project
+asset directory. The script and the cooked pair are the shipping sources.
+`Human.recipe.json` records the geometry digest and counts; a count is an identity
+check, never a visual-quality verdict. Repeated authoring produces the same curve
+arrays; Alembic container metadata is not used as a geometry determinism oracle.
+
+## Coordinates and contracts
+
+Roots are sampled on the scan's triangles with their interpolated glTF root UVs.
+There is a curved frontal hairline, clearance above the ears, and a narrow part.
+Small hairline irregularities and a 3 mm density taper soften the forehead edge.
+The part's roots have 2.5 times the base density. Short regrowth from those
+sampled follicles combs backwards beneath the long locks, keeping the part
+covered through motion without turning the two sides into separate sheets.
+Regrowth uses the existing undercoat role and tapered 60–85 micrometre fibres;
+the scene's guide caps remain 512 long-hair and 128 undercoat guides.
+Voronoi locks are separated at the part; each lock follows the scalp before a
+tangent-continuous hanging section. Arc-length sampling concentrates controls
+near the scalp to follow its curvature. The curves
+carry tapered 65–95 micrometre root diameters. Guides and card-cook settings ride
+on Blender's hair-curve attributes and Alembic user properties. Locks gather
+less at their tips and individual fibres shorten along the tip tangent by up
+to 12 mm. Short emergence hairs soften the front boundary above the eyes.
+The ellipsoid is only a styling scaffold: non-root controls that enter the scan
+are projected onto its triangles with 6 mm crown volume and 1 mm lower clearance.
+The extra crown volume gives the dynamic guides room to sag above the scanned
+surface; flush arcs sank under the scalp despite correct root binding.
+The sampled roots stay
+on the actual bind surface. The recipe records the number and largest correction.
+
+HumanCoat uses the existing guide solver with stiffness 2000, damping 12 and
+gravity `[0, -4, 0]`, within its supported range. This is the same reduced-gravity
+authoring convention used by the short-coat showcase, with full simulation and
+collision enabled. The earlier stiffness 90 treated the scalp arcs like rope,
+pulling them into the head and across the eyes during runtime even though the
+static editor groom and binding checks looked correct.
+
+The historical Human groom frame contains GroomAnimals' head placement
+`[0, 1.24, 3.6]`. Blender uses Z up and faces -Y; its Alembic export converts
+back to the engine's Y-up, +Z-facing frame. The binding is cooked with the body's
+placement in that same frame. Changing it requires re-cooking both files.
+
+`GroomAnimalsCookedBinding.HumanHairFramesTheFaceAndClearsTheShoulders` pins the
+rest geometry's eye/cheek corridor and shoulder clearance. Cold/warm binding,
+pack parity, runtime motion and inspected multi-angle frames remain separate
+requirements; the rest-geometry contract cannot establish those.
+`SkinRiggedHeadCloseUp.NativeHairAuthoringEvidenceOnEveryPath` captures 1080p
+views, physical fibre lobes, a hair-off control and the full 7.24-second LookAround
+clip through the real OpenGL Scene pipeline. `NativePackedHairKeepsItsCookedPairAndBinding`
+checks the shipping pair through AssetPackBuilder and RuntimeAssetManager.
+The full generated image matrix is ignored; curate review images separately.
+
+For a cold standalone game check, set `OLO_HUMAN_HAIR_GAME` to an absolute scratch
+directory and run `SkinRiggedHeadCloseUp.ExportsHumanHairGame`. It calls the real
+GameBuildPipeline with this pair, the actual skin profile and staged model dependencies.
+Launch `HumanHair1593/HumanHair1593.exe --rhi=opengl` or `--rhi=vulkan` with its game
+directory as the working directory. The native runtime client was inspected on both
+backends; see [the evidence report](../../../../../docs/analysis/digital-human-hair-quality-1593.md).
+
+The scan-derived hair roots retain the scan's **CC BY 3.0** attribution chain:
+Lee Perry-Smith / Infinite, Morgan McGuire and Guedis Cardenas, and Keijiro
+Takahashi. See [the scan's licence](../../../../assets/models/InfiniteScanHead/LICENSE.md)
+and [attribution](../../../../assets/models/InfiniteScanHead/README.md).