World Labs Marble

Marble is World Labs' commercial multimodal world model: it lifts a text prompt, image(s), video, panorama, or coarse 3D blocking into a persistent, downloadable 3D environment you can navigate, edit, expand, and export. World Labs was co-founded by Fei-Fei Li; Marble reached general availability on 2025-11-12 and a programmatic World API was announced 2026-01-21. (Documented; verified 2026-07-10.)

The defining property, and the thing that separates Marble from most "generative video" or interactive world models: the world is materialized as persistent 3D geometry (Gaussian splats and/or meshes) that you own as a file, rather than hallucinated frame-by-frame as you walk. That makes it usable as a production asset, not just a demo you watch. (Documented — worldlabs.ai blog; verified 2026-07-10.)

When to use this skill

Use it when the deliverable is a 3D space:

• An explorable environment for VR (Quest 3, Vision Pro), a web viewer, or a game engine.
• A virtual-production / previz backdrop, a set blockout, or an environment concept that must hold up from multiple camera angles.
• A programmatic pipeline that needs many worlds generated on demand (World API).
• Turning a single photo, concept art, or a location video into a navigable set.

Do not reach for Marble when the user wants a flat image (use an image model), a short talking/action video clip (use a video model), or a real-time game engine that streams infinite world on the fly. Marble worlds are bounded, static environments — extremely detailed, but not simulations with moving actors or physics baked in.

Access routes (verify — these are volatile)

As of 2026-07-10 there are two first-party routes; both are live:

Route	Where	Auth	Billing	Best for
Marble web app	marble.worldlabs.ai	Account login	Monthly subscription (Free/Standard/Pro/Max)	Hands-on authoring, Chisel, Studio (Compose/Record), interactive editing
World API	platform.worldlabs.ai, endpoint base api.worldlabs.ai/marble/v1	WLT-Api-Key header	Prepaid credits (separate wallet)	Automated/batch generation, product integrations

Critical, easily-missed fact: app credits and API credits are separate wallets. Credits bought for the Marble app cannot be spent on the API, and vice versa. Budget them independently. (Documented — docs.worldlabs.ai/api/pricing; verified 2026-07-10.)

There is a published AI-agent skill for the API (docs.worldlabs.ai/api/agent-skill) intended for coding agents that drive the World API directly.

Models (choose deliberately — cost and quality differ)

Documented model line as of 2026-07-10 (docs.worldlabs.ai/marble/models, release notes 2026-04-02):

• marble-1.1 — the recommended default. Improved quality at a fixed generation cost. Start here for most single-scene work.
• marble-1.1-plus — auto-expanding worlds: covers more 3D space in one shot when the scene allows. Variable cost (bigger world = more credits). Use when you need a genuinely large, walkable expanse from one generation.
• marble-1.0 — legacy; keep only for continuing older projects.
• marble-1.0-draft — fastest and ~10× cheaper. Use for prompt/iteration scouting before committing a full-quality generation. Draft output is lower fidelity by design.

Heuristic (production): iterate prompts and framing on draft, then promote the winning prompt/seed to 1.1; reserve 1.1 Plus for hero shots that must be large. Reusing the seed keeps a concept stable while you change one variable.

Input modes and their constraints

Marble accepts five prompt types. Match the mode to how much control you have and need (documented — docs.worldlabs.ai/marble/create and API generate reference; verified 2026-07-10):

• Text — describe the world in natural language. Most freedom, least control over exact appearance. Good for ideation and stylized worlds.
• Single image — lifts a photo or artwork into 3D. The image fixes the look from one direction; Marble invents the rest. Marble auto-detects an equirectangular panorama if you supply one.
• Multiple images — up to 4 images (up to 8 in reconstruction mode via the API), each tagged with a direction/azimuth (Front/Back/Left/Right) or Auto Layout. Use when you must control what the world looks like from several angles.
• Video — a short clip of a real location. Formats MP4/WebM/MOV/AVI, max 100 MB (API limit raised to 100 MB on 2026-01-29). Best for rotational or walk-through coverage of an existing place.
• 360 panorama — an equirectangular image. Maximum spatial control of any 2D input because it pins the full surround; the API can also generate a panorama for you (/pano endpoints).

The more the input constrains geometry (panorama > multi-image > single image > text), the more predictable the world — but the less Marble invents. Pick the weakest constraint that still gets the look you need. (Production heuristic.)

Chisel — structure/layout control

Chisel (documented; the current name as of 2026-07-10) is Marble's coarse-3D blocking tool. It decouples structure from style: you lay out the spatial skeleton in 3D, then a text (or image) prompt paints the look onto it.

What Chisel gives you (docs.worldlabs.ai/marble/create/chisel-tools):

• Primitives — boxes and planes; a wall tool for vertical segments (room boundaries) and an extrude function for depth/volume.
• Import existing 3D assets — GLB and FBX models can be brought in as blocking and restyled cohesively into the generated world.
• A panorama camera you position to set where the detailed generation originates.

Use Chisel when layout matters: room proportions, door/window placement, architectural footprints, or matching a real set's dimensions. It is the right tool when a pure text or image prompt keeps giving you the right style but the wrong floor plan. (Production heuristic.)

Editing, expansion, and Studio tools

• Create & Edit / AI-native editing — remove or swap objects, touch up regions, or restyle the whole world with prompts. Surfaced through the omnibox (release notes 2026-04-02).
• Pano Edit — natural-language edits targeted at regions of the panorama.
• Expand — select a region and grow the world beyond its original bounds (the "click and expand" idea), or add detail to weak/low-fidelity areas. Expansion is gated to Pro/Max subscription tiers.
• Variations — generate alternate versions that keep the core scene.
• Compose (Studio) — arrange multiple worlds together with full control of layout; supports importing meshes into the Composer (release notes 2026-01-29).
• Record (Studio) — author cinematic camera flythroughs with pixel-accurate paths and export video, including "enhanced video" that adds detail and dynamic elements (e.g. smoke, flowing water) to the render.

Note the important distinction: dynamic elements live in the video export, not in the exported 3D geometry. The splat/mesh you download is static. (First-party + production observation; verified 2026-07-10.)

Output formats and what each supports downstream

Documented export specs (docs.worldlabs.ai/marble/export/specs and mesh; verified 2026-07-10):

Format	Detail	Downstream fit	Tier/limit
Gaussian splat — SPZ	Marble-native, size-optimized; ~2M or ~500k splats	Marble's own renderer; Spark (web/Three.js)	Highest visual fidelity
Gaussian splat — PLY	Uncompressed, broad tool compatibility	Blender/Houdini/Unity/Unreal splat plugins	Same fidelity, larger files
Collider mesh (GLB)	~100–200k triangles, ~3–4 MB, instant	Physics/collision in engines	Standard+; not for display
High-quality mesh (GLB)	~600k tris (textured) and ~1M tris (vertex-colored), 100–200 MB	Editable geometry for DCC/engines	Pro; up to ~1 hr to generate; rate-limited ~4/hr; owner-only
360 panorama (PNG)	Equirectangular, 2560×1280	Skyboxes, matte refs	—
Video	Camera-path render, optional enhancement	Previz, social, edit	Enhancement/expansion gated to Pro+

Decision rule: Gaussian splats for visual fidelity, meshes for interaction. If you need the best-looking result and the target can render splats (web via Spark, or an engine plugin), export SPZ/PLY. If you need collision, physics, or a watertight editable object, export the mesh — collider mesh for physics only, high-quality mesh for visuals-plus-geometry. Both mesh variants exist because reconstruction quality varies by scene; pick whichever version reconstructs your scene better. (Documented + heuristic.)

Coordinate gotcha: exports default to OpenCV coordinates. For OpenGL-based software, scale Y and Z by −1 (or choose the OpenGL option added 2026-01-01) or the world imports inverted. (Documented; verified 2026-07-10.)

Importing into engines and DCC tools

Marble documents Gaussian-splat import paths for Unity, Unreal Engine, Blender, and Houdini (each via that tool's Gaussian-splatting plugin) and Spark for custom web/Three.js apps; there are open-source interactive examples that combine a world with rendering and physics (docs.worldlabs.ai/marble/export). Practical path:

• Web / lightweight interactive → SPZ + Spark (sparkjs.dev).
• Unity / Unreal → PLY splat via the engine's splat plugin for visuals; collider mesh GLB alongside it for physics.
• Blender / Houdini (look-dev, matte, VFX) → PLY splat or high-quality mesh.

Because splat rendering still relies on third-party plugins in most engines, confirm the target engine/version has a working Gaussian-splat renderer before you commit a splat-only pipeline; fall back to the high-quality mesh where it doesn't. (Production heuristic.)

Pricing and credits (volatile — verify at purchase time)

Marble app subscription tiers (secondary-source-corroborated: The Batch / deeplearning.ai and docs; verified 2026-07-10 — confirm live figures before relying on them):

Tier	Price	Generations/mo	Notable unlocks
Free	$0	~4	Text, single image, or 360 panorama
Standard	~$20/mo	~12	Multi-image, video, 3D-layout inputs; editing; collider-mesh export
Pro	~$35/mo	~25	Expansion, video enhancement, high-quality mesh export, commercial rights
Max	~$95/mo	~75	All features, highest volume

World API credits (documented — docs.worldlabs.ai/api/pricing; verified 2026-07-10):

• $1.00 per 1,250 credits; minimum purchase $5.00 (6,250 credits).
• API credits do not expire; auto-refill configurable; 402 on empty balance.
• Cost per generation: draft ~150–250 credits (cheapest for pano-from-image); 1.0 / 1.1 ~1,500–1,600 credits; 1.1 Plus ~1,500 base scaling up to ~3,000 depending on world size (variable "dynamic cube" cost).

Rough rule of thumb: a full-quality API world (~1,500 credits) ≈ $1.20; a draft ≈ $0.12–$0.20. Budget accordingly and scout on draft.

Capability limits (state these to users up front)

• Static, bounded worlds. No baked-in moving actors, animation, or simulation in the exported geometry; dynamism appears only in video renders.
• World size is finite; 1.1 Plus and Expand push the bounds but do not produce infinite streaming worlds.
• Reconstruction artifacts are expected in thin structures, transparent or reflective surfaces, and areas the input never showed (occluded backs, undersides). Marble invents unseen regions plausibly, not accurately.
• High-quality mesh takes up to ~1 hour, is rate-limited (~4/hr), and is Pro-tier/owner-only.
• Mobile app support is limited vs desktop.

(Documented + first-party; verified 2026-07-10.)

Quality review criteria for a generated world

When reviewing a Marble world for production use, walk (don't glance) and check:

1. Seams and holes — orbit the camera; look for tears where expansion or panorama edges meet, and floating/missing geometry behind foreground objects.
2. Ground plane — is the floor coherent and level, or does it dish/warp? Matters most for game blockouts and physics.
3. Occluded regions — the sides/backs the input never saw are the weakest; judge whether your camera will ever see them.
4. Thin/transparent/reflective elements — railings, foliage, glass, water: the usual artifact sources. Decide if a mesh export will hold up or if you should stay in splats.
5. Scale — with real-world unit scaling (added 2026-01-01), confirm dimensions match your set/engine before importing.
6. Style consistency — after edits/compose, confirm lighting and style read as one coherent space, not stitched fragments.
7. Format fit — did you export the right thing (splat for looks, collider for physics), and does the target renderer actually support it?

If artifacts sit only outside the intended camera path, the world may be production-ready as-is. If they're on-camera, prefer Expand/edit or a re-generation with a stronger input (add a panorama or multi-image) over patching in a DCC. (Production heuristic.)

Rights and licensing (get this right — it gates commercial delivery)

Documented / first-party (worldlabs.ai Terms of Service and product docs; verified 2026-07-10):

• Free-tier output: World Labs retains rights; the user gets a revocable, non-exclusive license for personal, non-commercial use only.
• Paid-tier output: the user owns the outputs and may use them commercially, excluding World Labs' own products/technology/IP — subject to the TOS.
• In the Marble product's own tiering, commercial rights are attached to Pro and Max. Treat Standard as effectively non-commercial for delivery purposes despite being a paid tier, and verify the current tier's commercial grant in the live TOS before shipping client work. (This app-tier gating vs. the TOS "paid account" language is a known ambiguity — resolve it against the live terms for the specific plan, do not assume.)
• You are responsible for your inputs: don't feed copyrighted images, trademarked material, or a real person's likeness you have no rights to into a world you intend to distribute.

When advising a user, always tie the recommended plan to the intended use: a commercial deliverable needs Pro or above (or a paid API entitlement) — recommending the Free tier for client work is a rights error.

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Complete examples (labeled; adapt, do not copy verbatim)

Example A — VR walkthrough of a fictional location (web app, panorama input)

• Intent: an explorable VR scene of a "moss-covered abandoned subway platform" for a Quest 3 web experience.
• Model/route: Marble web app; scout on marble-1.0-draft, finalize on marble-1.1.
• Input & why: start from a 360 panorama (rendered or shot) rather than text — a panorama pins the full surround so the platform reads coherently in every head direction, which VR demands.
• Workflow: draft-generate → check ground plane and seams → promote prompt + seed to 1.1 → Expand the tunnel mouths to lengthen the platform → export SPZ → render on the web with Spark.
• Parameters: reuse seed across draft→final; keep world private until reviewed.
• Expected result: a seamless, walkable platform holding up under free head movement.
• Likely failure modes: warped ground, artifacts on tunnel-mouth edges after expansion, thin railing tearing — review by orbiting before export.
• Variations: multi-image (4 angles) if you have reference photos; mesh export if the VR app needs collision.

Example B — Game environment blockout matching a set floor plan (Chisel)

• Intent: a first-pass playable blockout of a two-room interior with a specific door position, for greyboxing in Unity.
• Route/model: web app, Chisel → marble-1.1.
• Input & why: Chisel, because layout is the constraint. Text prompts gave the right style but the wrong floor plan; blocking walls/door in 3D fixes geometry, and the prompt only styles it.
• Workflow: wall-tool the two rooms and the doorway → position the panorama camera at the play-start point → prompt "warehouse office, worn concrete, fluorescent light" → generate → export collider mesh GLB (physics) + PLY splat (visual) → import both into Unity (splat plugin + collider).
• Expected result: proportions and door placement match the intended plan; greyboxing can start against real collision.
• Likely failure modes: collider mesh too coarse for precise interactions (it's meant to be simple); high-quality mesh needed later for visual polish.
• Variations: import an existing GLB/FBX prop into Chisel to have it restyled into the scene.

Example C — Batch backdrops via the World API (programmatic)

• Intent: generate 30 varied "alien desert" backdrops for a virtual- production pre-light, unattended overnight.

• Route/model: World API, marble-1.1 (fixed cost for predictable budget).

• Request (illustrative JSON body to POST api.worldlabs.ai/marble/v1/worlds:generate, header WLT-Api-Key):

  {
    "world_prompt": { "type": "text",
      "text_prompt": "vast alien desert, twin suns, wind-carved rock arches" },
    "display_name": "alien-desert-07",
    "model": "marble-1.1",
    "seed": 7,
    "tags": ["previz", "desert"],
    "permission": { "public": false }
  }
  

• Async handling: the call returns an operation_id; poll /operations/{operation_id} until done, then read the world and call the export endpoint for SPZ. Charge (cost) is reported on success.

• Budget: ~1,500 credits each ≈ ~$1.20 × 30 ≈ ~$36 in API credits; scout one or two prompts on draft first to lock the wording.

• Expected result: 30 distinct, private worlds ready to pull into the virtual-production toolchain.

• Likely failure modes: 402 on empty credit balance (enable auto-refill); same-seed sameness across prompts (vary seed and prompt); over-spend from jumping straight to 1.1 Plus without draft scouting.

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Sources (verified 2026-07-10 unless noted)

Primary / first-party:

• Marble docs home & index — https://docs.worldlabs.ai/ , https://docs.worldlabs.ai/llms.txt
• Models — https://docs.worldlabs.ai/marble/models.md
• Create / input modes — https://docs.worldlabs.ai/marble/create/index.md and prompt guides
• Chisel — https://docs.worldlabs.ai/marble/create/chisel-tools/chisel-basics.md
• Export specs & mesh — https://docs.worldlabs.ai/marble/export/specs.md , https://docs.worldlabs.ai/marble/export/mesh.md
• API pricing — https://docs.worldlabs.ai/api/pricing
• API generate reference — https://docs.worldlabs.ai/api/reference/worlds/generate.md
• Subscriptions & billing — https://docs.worldlabs.ai/marble/support/account-billing
• Release notes — https://docs.worldlabs.ai/marble/release-notes.md
• Marble launch blog — https://www.worldlabs.ai/blog/marble-world-model (2025-11-12)
• World API announcement — https://www.worldlabs.ai/blog/announcing-the-world-api (2026-01-21)
• Bigger & Better Worlds — https://www.worldlabs.ai/blog/bigger-better-worlds (beta 2025-09-16)
• Terms of Service — https://www.worldlabs.ai/terms-of-service

Secondary (disclosed-method, used only where first-party pages were SPA shells, e.g. exact consumer dollar tiers):

• The Batch / deeplearning.ai — https://www.deeplearning.ai/the-batch/world-labs-makes-its-marble-generative-world-model-public-adds-chisel-editing-tool/
• TechCrunch — https://techcrunch.com/2025/11/12/fei-fei-lis-world-labs-speeds-up-the-world-model-race-with-marble-its-first-commercial-product/

Volatile facts (model names, credit costs, subscription prices, access routes, export limits) are dated above; re-verify against the live docs and pricing pages before relying on them for a purchase or a delivery decision.