fal-regenerate-3d Skill

Runtime: Asset generation steps run via the genmedia CLI (FLUX.2 / GPT-Image-2 / Meshy v6 / Seedance / etc.). The final deliverable is a static HTML page with Three.js, generated assets are bundled into it. See the genmedia skill for command syntax; run genmedia init once if not yet installed.

End-to-end recipe to ship a polished, multi-character 3D web experience using fal.ai models. This is the recipe that powers fal-roster.vercel.app: a cyberpunk character selector with 10 unique operatives, each with a matching companion creature, environment-themed floor texture, animated background and color palette.

What it builds

For each character you get:

• A stylized 3D character GLB (rigged + animated, baked into the file)
• A companion creature GLB (small static, themed to match the character)
• A per-character PBR floor (basecolor / normal / roughness / metalness, all generated)
• A looped video background keyed to the biome
• A 3-color palette that drives the whole UI (CSS custom properties)
• A portrait crop for the roster card

All packaged into a single static HTML page with a Three.js scene. ~25–35 MB of GLBs total after compression.

Pipeline

1. GPT-Image-2 → 1024x1536 character full-body T-pose (per character)
2. Meshy v6 → image-to-3d, enable_rigging=true, animation_action_id={chosen}
 → animated GLB (idle, dance, alert, etc.)
3. GPT-Image-2/edit → companion creature image, color-locked to character palette
4. Meshy v6 → image-to-3d, enable_rigging=false → static creature GLB
5. PATINA → fal-ai/patina/material/extract on the character image,
 returns basecolor + normal + roughness + metalness for the floor
6. Seedance 2.0 → fal-ai/bytedance/seedance-2.0/fast/image-to-video, 8s loop
7. gltf-transform CLI → resize 1024 → webp q80 → draco
 (typically 95–96% size reduction, ~400–800 KB final)
8. Three.js scene → MeshStandardMaterial floor with alphaMap circular cutout,
 mirrored reflection (refl.y = root.y, scale.y = -1),
 breathing animation on companions,
 per-character palette via CSS custom properties (--c1/--c2/--c3),
 per-character floor texture swap on character click,
 transition lines + radial flash on swap

CREATE-YOUR-OWN flow

Visitors with a FAL key can generate their own character + companion live, in-browser:

flux-2 klein 9b (text-to-image)
 └─ character full-body image
 ├─ Meshy v6 (rigged + animated) → character GLB
 └─ flux-2 klein 9b/edit → companion image
 └─ Meshy v6 (no rig) → companion GLB

Cost: ~$2–3 per generation (4 fal calls). Runs in background, modal closes on Generate so the user can keep using the experience while the gen runs. The CREATE YOUR OWN tile transforms into a loading state, then becomes the new character card with a ↻ re-create button.

Key fal endpoints used

Step	Endpoint
Character image (curated)	openai/gpt-image-2
Character image (live)	fal-ai/flux-2/klein/9b
Companion image	fal-ai/gpt-image-2/edit or fal-ai/flux-2/klein/9b/edit
3D character/companion	fal-ai/meshy/v6/image-to-3d
Per-character floor PBR	fal-ai/patina/material/extract
Background video	fal-ai/bytedance/seedance-2.0/fast/image-to-video
Logo / icon cleanup	fal-ai/bria/background/remove

Meshy animation IDs

Curated dance / idle action IDs (full list at https://docs.meshy.ai/en/api/animation-library):

ID	Animation
0	Idle (default)
2	Alert
36	Confused (scratch)
48	Mirror viewing
64	All_Night_Dance
405	Joyful_Dance_with_Hand_Sway
591	Hip_Hop_Dance
64–83	Various Pop_Dance variants

Three.js scene notes

• Floor: PlaneGeometry(7, 7, 220, 220) cut into a disc via radial-gradient alphaMap. High tessellation enables real displacementMap (uses basecolor as height).
• Reflection: clone of the root with scale.y = -1, BackSide, depthWrite = false, renderOrder = -1. For characters whose origin is at the feet, refl.position.y = root.position.y produces a visible mirror; the floor's transparent = true; opacity ≈ 0.5 lets it bleed through.
• Breathing: per-frame scale.setScalar(base * (1 + sin(t*1.3)*0.025)) + a small Y bob on companions. The reflection mirrors the bob so the mirror stays consistent.
• Palette swap: :root.style.setProperty('--c1', hex) etc. Every UI element (sparklines, pulses, bars, model pills, edge map dots) derives its color from var(--c1) / var(--c2).
• Floor swap: texLoader.load() 4 PBR maps from assets/floor/{charId}/, dispose old textures, set floorMat.color back to white (since the basecolor is already char-themed).
• Transition: 9 diagonal lines sweep across the viewport (@keyframes tfx-sweep) on character click + a radial flash; bg video crossfades between two <video> elements; character GLB slides out and the new one slides in.

Reference implementation

• Live: https://fal-roster.vercel.app
• Source: https://github.com/lovisdotio/fal-roster
• Skill repo: https://github.com/lovisdotio/skills-fal-ai

Cost reference (curated build)

For one full character:

Step	Approx. cost
1 GPT-Image-2 (character)	$0.04
1 Meshy v6 rigged + animated	$0.80
1 GPT-Image-2/edit (companion)	$0.04
1 Meshy v6 static (companion)	$0.20
1 PATINA floor (4 maps)	$0.04
1 Seedance fast (bg video)	$0.08
Total per character	~$1.20
10 characters	~$12

Runtime parallelizes well, the original 10-character set was generated in ~10 minutes wall-clock with 9 concurrent jobs per stage.