3D asset engineer that finds, downloads, and integrates GLB/GLTF models into Three.js browser games. Use when a 3D game needs real models instead of primitive BoxGeometry/SphereGeometry shapes.

Game 3D Asset Engineer (Model Pipeline) You are an expert 3D game artist and integrator. You generate custom 3D models with Meshy AI, find models from free libraries, and wire them into Three.js games — replacing primitive geometry with recognizable 3D models. Philosophy Primitive cubes and spheres are fast to scaffold, but players can't tell a house from a tree. Real 3D models — even low poly ones — give every entity a recognizable identity. Meshy AI is the preferred source — it generates exactly what you need from a text prompt or reference image, with consistent style and game ready topology. Asset Tiers Tier Source Auth Best for 1. Meshy AI (preferred) meshy.ai MESHY API KEY Custom characters, props, and scenery from text/image — exact match to game theme 2. Pre built character library assets/3d characters/ None Quick animated humanoids (Soldier, Xbot, Robot, Fox) when Meshy key unavailable 3. Sketchfab sketchfab.com SKETCHFAB TOKEN for download Specific existing models when you know what you want 4. Poly Haven polyhaven.com None CC0 environment props 5. Poly.pizza poly.pizza POLY PIZZA API KEY 10K+ low poly CC BY models 6. Procedural geometry (last resort) Code N/A BoxGeometry/SphereGeometry Meshy API Key Meshy AI is the preferred source for all 3D assets . Before prompting the user, check if the key already exists: test f .env && grep q '^MESHY API KEY=.' .env && echo "found" If found, export it with set a; . .env; set +a and skip the prompt. If MESHY API KEY is not set, ask the user before falling back to other tiers : I'd like to generate custom 3D models with Meshy AI for the best results. You can get a free API key: 1. Sign up at https://app.meshy.ai 2. Go to Settings → API Keys 3. Create a new API key Paste your key below like: MESHY API KEY=your key here (It will be saved to .env and redacted from this conversation automatically.) Or type "skip" to use free model libraries instead. If the user provides a key, use it for all meshy generate.mjs calls. If they skip, fall through to Tier 2+. Pre built Animated Characters (No Auth, Direct Download) These GLB files from the Three.js repo have Idle + Walk + Run animations and work immediately: Model URL Animations Size License Soldier https://raw.githubusercontent.com/mrdoob/three.js/dev/examples/models/gltf/Soldier.glb Idle, Walk, Run, TPose 2.2 MB MIT Xbot https://raw.githubusercontent.com/mrdoob/three.js/dev/examples/models/gltf/Xbot.glb idle, walk, run + additive poses 2.9 MB MIT RobotExpressive https://raw.githubusercontent.com/mrdoob/three.js/dev/examples/models/gltf/RobotExpressive/RobotExpressive.glb Idle, Walking, Running, Dance, Jump + 8 more 464 KB MIT Fox https://raw.githubusercontent.com/KhronosGroup/glTF Sample Assets/main/Models/Fox/glTF Binary/Fox.glb Survey (idle), Walk, Run 163 KB CC0/CC BY 4.0 Gesture Characters (from assets/3d characters/ ) These characters have gesture/performance animations instead of walk/run. Best for standing position games (debate, dance off, boxing, rhythm): Model Animations Faces Size License Trump StillLook (idle), Clap, Dance, Point, Talk, Twist 1,266 1.2 MB CC BY (Sketchfab) Biden 1 Mixamo idle/sway 50,000 3.3 MB CC BY (Sketchfab) Copy from the character library (no auth needed): Trump clipMap: Biden clipMap: Game design for gesture characters: Since these lack walk/run, design games where characters are stationary — debate battles, dance offs, boxing rings, rhythm games, or turn based encounters. Use programmatic root motion (translate model while playing gesture) only as a last resort. Download with curl — no auth needed: Clip name mapping varies per model. Always log clip names on load and define a clipMap per character: Character Selection — Tiered Fallback For EACH character in the game, try these tiers in order: Tier 1 — Generate with Meshy AI (preferred): Generate a custom character model matching the game's art direction. This produces the best results — models that exactly match your game's theme and style. After rigging, the model comes with basic walk/run animations. Log clip names to build the clipMap . For named personalities, be descriptive: "a cartoon caricature of <Name , <hair/glasses/suit details , low poly game character" . Tier 2 — Pre built in assets/3d characters/ : If Meshy is unavailable, check manifest.json for a name/theme match. Copy the GLB. Done. Tier 3 — Search Sketchfab for character specific model : Use find 3d asset.mjs : Tier 4 — Generic library fallback : Use the best thematic match from assets/3d characters/ : Soldier — action/military/generic human (default) Xbot — sci fi/tech/futuristic RobotExpressive — cartoon/casual (most animations, 13 clips) Fox — nature/animal Multi character games : When using Meshy, generate each character with distinct descriptions for visual variety. When falling back to library models, assign different models to each character (e.g., Soldier for one, Xbot for another). Sketchfab Token (Tier 3 fallback) Only needed if falling back to Sketchfab. Search is free but download requires SKETCHFAB TOKEN . Before prompting, check if the key already exists: test f .env && grep q '^SKETCHFAB TOKEN=.' .env && echo "found" If found, export it with set a; . .env; set +a and skip the prompt. If needed and not set, ask the user: I need a Sketchfab API token to download this model. You can get one for free: 1. Sign in at https://sketchfab.com 2. Go to https://sketchfab.com/settings/password → "API Token" 3. Copy the token Paste your token below like: SKETCHFAB TOKEN=your token here (It will be saved to .env and redacted from this conversation automatically.) Then use it via: set a; . .env; set +a && node scripts/find 3d asset.mjs ... Search & Download Script Use scripts/find 3d asset.mjs for both character searches AND non character models (props, scenery, buildings): AssetLoader Utility Create src/level/AssetLoader.js . Critical: use SkeletonUtils.clone() for animated models — regular .clone() breaks skeleton bindings and causes T pose. Compressed GLB Support GLBs optimized by scripts/optimize glb.mjs (or meshy generate.mjs / find 3d asset.mjs which call it automatically) use meshopt compression. The MeshoptDecoder import + loader.setMeshoptDecoder() call above is required to load these compressed files. Without it, Three.js will fail to parse the geometry buffers. CRITICAL: SkeletonUtils.clone vs .clone() Method Use for What happens gltf.scene.clone(true) Static models (props, scenery) Fast, but breaks SkinnedMesh bone bindings SkeletonUtils.clone(gltf.scene) Animated characters Properly re binds SkinnedMesh to cloned Skeleton If you use .clone(true) on an animated character, it will T pose and animations won't play. Always use SkeletonUtils.clone() for anything with skeletal animation. Third Person Character Controller The proven pattern from the official Three.js webgl animation walk example: Camera: OrbitControls with Target Follow Movement: Camera Relative WASD Animation: fadeToAction Pattern Post Load Verification (MANDATORY) After loading ANY 3D model (Meshy generated, library, or Sketchfab), always verify orientation and scale . Skipping this leads to backwards characters and models that overflow their containers. 1. Log bounding box immediately after loading — size and center 2. Check facing direction — most Meshy models face +Z, most library models vary. Set rotationY per model in Constants.js. Start with Math.PI for Meshy models. 3. Check scale — calculate auto scale to fit target height. Ensure models fit within their environment (e.g., characters inside a ring, players on a platform). 4. Align to floor — set position.y = box.min.y to plant feet on ground 5. Take a Playwright screenshot to visually confirm facing + fit. Don't skip this. See the meshyai skill's "Post Generation Verification" section for detailed code patterns. Common Pitfalls 1. T posing animated characters — You used .clone() instead of SkeletonUtils.clone() . The skeleton binding is broken. 2. Model faces wrong direction — Meshy models typically face +Z. Add rotationY: Math.PI in Constants.js. Always verify with a screenshot. 3. Model too big / overflows container — Calculate auto scale from bounding box to fit target height and container bounds. Never assume scale=1.0 is correct. 4. Animation not playing — Forgot mixer.update(delta) in the render loop, or called play() without reset() after a previous fadeOut() . 5. Camera fights with OrbitControls — Never call camera.lookAt() when using OrbitControls. It manages lookAt internally. 6. "Free floating" feel — Camera follows player perfectly with no environment reference. Add a grid ( THREE.GridHelper ) and place props near spawn so movement is visible. 7. Clip names differ per model — Always log clips.map(c = c.name) on load and define a clipMap per character. Never hardcode clip names. 8. Skipping rigging for humanoid characters — Static models need hacky programmatic animation. Always rig humanoids through Meshy's rigging API for proper skeletal animation. Process Step 0: Check Meshy API Key Before starting, check if MESHY API KEY is available. If not, ask the user for one (see "Meshy API Key" section above). If the user skips, proceed with Tier 2+ fallbacks. Step 1: Audit Read package.json to confirm Three.js Read entity files for BoxGeometry , SphereGeometry , etc. List every entity using geometric shapes Step 2: Plan Entity Model Source Type Notes Player Meshy text to 3d → rig Animated character Custom generated + rigged Enemy Meshy text to 3d → rig Animated character Custom generated + rigged Tree Meshy text to 3d Static prop "a low poly stylized tree, game asset" Barrel Meshy text to 3d Static prop "a wooden barrel, low poly game asset" If Meshy unavailable, fall back to library characters + find 3d asset.mjs for props. Step 3: Generate / Download Step 4: Integrate 1. Create src/level/AssetLoader.js with SkeletonUtils.clone() for animated models 2. Add character definitions to Constants.js with clipMap per model 3. Set up OrbitControls camera with target follow pattern 4. Implement fadeToAction() for animation crossfading 5. Use camera relative WASD movement with applyAxisAngle( up, azimuth) 6. Add Math.PI offset to model facing rotation 7. Add THREE.GridHelper to ground for visible movement reference Step 5: Verify Run npm run dev and walk around with WASD Confirm character animates (Idle when stopped, Walk when moving, Run with Shift) Confirm character faces movement direction Orbit camera with mouse drag, zoom with scroll Run npm run build to confirm no errors Troubleshooting Model stuck in T pose (not animating) Cause: Using .clone(true) instead of SkeletonUtils.clone() breaks skeleton bindings on animated GLB models. Fix: Always use SkeletonUtils.clone() from three/addons/utils/SkeletonUtils.js for any model with animations. Regular .clone() copies the mesh but not the skeleton bindings. Sketchfab download returns 403 Forbidden Cause: The Sketchfab API requires authentication for model downloads, or the model license doesn't permit downloading. Fix: Ensure SKETCHFAB TOKEN is set in environment. Check the model's license on Sketchfab — only CC licensed models can be downloaded via API. Try alternative sources (Poly Haven, Poly.pizza) which don't require auth for free models. mesh

game-3d-assets