security-game/docs/blender-assets.md

Blender asset library

Architecture context: the asset contracts and fallback path are summarized in architecture.md.

Status: built, audited, and integrated (2026-11-01). NpcAvatar selects the character variants and attaches the gear; WorldBuilder loads the prop library with colliders and phase-driven emissives.

Generator: tools/blender_assets.py. Manifest (the source of truth for integration): assets/models/blender/manifest.json.

Art direction

The references were the AI mockups in docs/screens/designs/ and the current captures in docs/screenshots/.

• People (targeting_npc, joke_shop_queue, studio_arrival, crowd_panic, responder_arrival): ordinary adults in sweaters, jackets, long coats, hoodies and beanies; a security guard in a dark uniform with a cap and belt; a firefighter in a dark turnout coat with yellow reflective bands, a helmet and an SCBA tank. The current skinned npc_base is a set of boxes and cylinders with a flat face, so silhouette was the main gap.
• Props (prop_gallery, venue_overview, late_night_avenue, joke_shop_queue): the gallery mockup has an octagonal tapered bollard, a slatted bench with thin metal legs, an octagonal green litter bin with a slot and recessed panels, a stone planter with a lumpy shrub, a blue news box with a window and a slanted top, and a hydrant with caps and nozzles. The venue shots add ornate street lamps, palm trees, round stone pots with topiary, a chalkboard A-frame sign, a wall lantern, a bulb-lit marquee, glazed double doors, stair handrails and a dark sedan. Today's in-game props are primitive boxes, and the trees are cones.

Running it

# Build every asset (or --only a,b,c). Writes GLBs, .blend sources, manifest.
flatpak run org.blender.Blender --background \
  --python "$PWD/tools/blender_assets.py" -- build
# Cycles previews (CPU, ~3 s each) -> docs/blender_previews/<name>.png (gitignored)
flatpak run org.blender.Blender --background \
  --python "$PWD/tools/blender_assets.py" -- render
python3 tools/blender_assets.py sheet   # -> docs/blender_previews/sheet_<category>.jpg
python3 tools/blender_assets.py audit   # stdlib only; exit 1 on any issue
python3 tools/blender_assets.py fit     # head/clothing fit + bag-body clearance, per character
python3 tools/blender_assets.py list
godot --headless --path . --import      # after any rebuild

The flatpak cannot read /tmp and its cwd is /app/blender, so the script derives every path from its own location. A full build takes about 5 s; a full render about 2.5 min.

Layout

Kind	Path	Count
Characters (skinned)	assets/models/blender/npc/<name>.glb	8
Gear (static)	assets/models/blender/npc_gear/<name>.glb	18
Props (static)	assets/models/blender/props/<name>.glb	20
Editable sources	assets/models/blender_src/<name>.blend (.gdignored)	46
Review sheets	docs/blender_previews/sheet_{npc,npc_gear,props}.jpg	3

Conventions

• Blender is Z-up. The glTF exporter converts to Godot Y-up.
• Front = Blender −Y = Godot +Z, the face direction that NpcAvatar.yaw_towards() assumes.
• Foliage (street_tree, planter_box, round_planter) is a cluster of many small flat-shaded clumps plus outer clumps that break the silhouette, not one smooth blob. That is how the realism pass made the street greenery read as leaves; the three assets carry fresh AO maps (street_tree is 2,592 triangles).
• Grounded assets have their origin on the floor (min y ≈ 0). The two exceptions are wall_lantern (origin on the wall plate, at mount height) and marquee (origin at the wall where the canopy meets it, at canopy height).
• Units are metres, at the same scale as the current world (1.82 m characters).

Characters

All eight use the npc_base contract, so each one can replace npc_base.glb without code changes:

• mesh node npc_base under an armature that imports as Skeleton3D
• bones Head, HipL/R, KneeL/R, ShoulderL/R, ElbowL/R, HandL/R (plus Hips, Spine, Neck) at the same rest positions as npc_base. test_character_joints_line_up_with_npc_base checks this within 1 cm, so the animation proxies in _build_skinned_body() stay valid.
• material slots skin, cloth, pants, accessory, hair carry the same neutral assets/textures/npc/<slot>_{albedo,normal}.png maps, so Materials.npc_slot() tints them the same way it tints npc_base.
• budget ≤ 6000 triangles and ≤ 5000 vertices (glTF vertex count, after seam splits; CHAR_MAX_VERTS in tools/blender_assets.py, raised from 4000 for the 2026-11-01 face/hand pass). The current range is 3,974–5,026 triangles and 3,744–4,807 vertices.

Construction: the torso and limbs are one continuous Skin-modifier mesh, subdivided twice, decimated to 26 % with X symmetry, and cut at the waist, cuffs, sleeves and neck so the material borders are clean edge loops. The head is a separate part carrying the face detail: brow ridge, sclera/iris/upper-lid per eye, cheekbones, a nose with a bridge and tip, ears with lobes, and upper and lower lips. Hands have four fingers plus a thumb; sleeves end in a cuff ring. Hair, shoes and clothing layers are separate parts. Weights come from distance to the bone segments, limited by body region. Parts that should stay rigid (head, hands, shoes) get a single bone.

Character	layer_for() / look	Suggested roles	Preview gear
npc_casual	none: sweater/tee, short sleeves	tourist, confused visitor, intoxicated, guest	backpack, camera
npc_jacket	jacket: collar + placket	authorized staff, protester, guest	lanyard, clipboard
npc_coat	coat: knee-length coat, long hair	influencer, trespasser, violent threat	sunglasses, shoulder bag, phone
npc_vest	vest: hi-vis vest, reflective bands	delivery	cap, clipboard
npc_dress	dress: slim build, bun, tights	performer	shoulder bag
npc_hoodie	hood accessory: hood up, beard, pocket	trespasser, mental crisis, violent threat	cup
npc_firefighter	responder: broad build, banded turnout coat, boots	responder	helmet, SCBA tank, flashlight
npc_guard	uniform: belt, buckle, badge, shoulder patches, radio	player guard / venue security	cap, wand

Fixed-colour materials. Detail materials outside the five slots (hivis, reflective, leather, steel, patch, plastic_black, rubber) carry a 4×4 colour texture. The current _apply_outfit_materials() sets albedo_color = WHITE on any slot it does not recognise, and these keep their colour through that. When integrating, tint only the five contract slots.

Runtime tint notes (implemented). Only the five contract slots are tinted; fixed detail materials keep their authored colour. On npc_vest the vest is the fixed hivis material and cloth is the undershirt, so the yellow override is skipped. npc_firefighter/npc_guard use dark turnout/uniform tints instead of the role's TYPE_COLORS.

Gear attach points

Gear is authored in attach-point space, so the origin of each GLB is its attach point:

Attach	Godot parent / position	Gear
head	Rig/Head marker (0, 1.62, 0)	cap, beanie, hood, sunglasses, firefighter_helmet
back	Rig at (0, 1.10, 0), spine centre; items sit behind the body (Blender +Y = Godot −Z)	backpack, shoulder_bag, scba_tank
chest	Rig at (0, 1.30, 0), sternum	lanyard
hand	Hand proxy (±0.27, 0.78, 0.02); grip 5 cm below the origin	phone, cup, clipboard, umbrella, camera, protest_sign, flashlight, wand, radio

The character previews in sheet_npc.jpg are built by importing the gear at exactly these points, which gives a quick visual check of the convention. NpcAvatar.GEAR_OFFSETS applies two final-context nudges after attachment: the lanyard moves 4 cm forward so its badge clears the jacket, and the firefighter helmet moves 3 cm up so its brim sits above the eyes. The fit report remains an asset-space measurement of the untouched GLBs.

Props

Prop	Replaces / role	Notes
bollard, bench, trash_bin, planter_box, newspaper_box, fire_hydrant	assets/models/generated/<name>.glb	same footprint and height as the generated set, so colliders and PROP_PLACEMENTS still fit
street_lamp	the box lamps in _build_street_furniture()	5 m; the arm points to −X with the bulb at (−0.85, 4.8, 0). Rotate 180° for the other side of the street. Emissive bulb
street_tree	the cone trees	3.6 m, with a tree grate
traffic_cone	the cone prop accessory	0.69 m
palm_tree	new (boulevard)	7 m, 14 fronds
round_planter	new (mockup pots)	stone pot with topiary
a_frame_sign	new (comedy club queue)	chalkboard
wall_lantern	new (club door)	wall-mounted; emissive bulb
crowd_barrier, stanchion	new (queue / crowd control)	2.2 m bike-rack barricade; chrome post with velvet rope
handrail	new (steps)	2 m run that climbs 0.8 m along +X
security_podium	new (door check-in)	tablet screen is mildly emissive
double_door	the procedural entrance door	2.0 × 2.7 m; emissive lock_led on the card reader
marquee	the procedural marquee	6 m canopy and sign box; emissive bulb + sign_face. Overlay the text with the existing Label3D
sedan	new (studio arrival)	4.6 m; emissive headlight, red tail lamps

Props use plain PBR factors (base colour, roughness, metallic, emission) plus the committed 256² baked AO maps (<name>_ao.png) wired by WorldBuilder; emissive materials are tied to WorldBuilder.set_night_mode(). Characters carry baked AO and the shared neutral material maps described above.

Checks

• python3 tools/blender_assets.py audit: container, POSITION/NORMAL/ TEXCOORD_0, UVs in [0, 1], no zero-area triangles (Godot warns about them during LOD generation), budgets (characters 6000/5000, gear 1500, props 4000 triangles), grounding, and an editable .blend. For characters it also checks skinning, bones, slots, the npc_base mesh node and the height.
• tools/test_blender_assets.py: catalogue and contract consistency with npc_pipeline.py, plus a clean audit and full manifest coverage when the library is built.
• src/test/tests/test_blender_assets.gd: every asset imports as a scene with geometry, characters keep their bones and slots, joints match npc_base, the bones accept NpcAvatar's pose composition, and props are grounded.

Known limitations

• Characters carry a baked <name>_ao.png (red channel, wired by _apply_outfit_materials()), but no ORM texture of their own. They reuse the tiling slot maps, so the runtime SurfaceMaterials recipes still supply roughness.
• There is a single body topology per build (average, slim, broad) and no shape keys. Height variety still comes from outfit_for()["height_scale"].
• Skirts and coats follow the hip and knee bones, so a full stride can clip the legs through the hem.
• Preview colours (PREVIEW_TINTS) only stand in for outfit_for(). The GLBs stay neutral.