Atlas World Model for game development: from prompt to Unity and Unreal

World models are the fastest way to get a believable environment into an engine, and World Labs’ models are the ones that output files rather than just video. This guide, from an independent site not affiliated with World Labs, Unity or Epic, covers what you get, how to bring it into Unity, Unreal, Blender and Godot, and what it costs. Everything described works with Marble today; Atlas produces the same family of assets and slots in when access opens.

What you actually get

The native output of a World Labs world is a Gaussian splat: millions of small, semi-transparent, oriented ellipsoids with colour and opacity. Splats capture soft lighting, foliage and glass better than meshes and render fast on modern GPUs, but they are visual only. They have no surfaces for collision, no UVs, and no material slots.

Marble exports splats as .spz and .ply, plus a mesh and a video, with PLY export free through the API (Radiance Fields). Atlas outputs point clouds and splat scenes “that render on device” (The Decoder); its mesh export is not documented yet.

So the decision for every asset is: splat for visuals, mesh for physics, or both.

Workflow overview

1. Author the input. A text prompt for an imagined place, one image for concept art, several overlapping photos for a real location, or a 360° panorama. All are accepted by the World API (World Labs); on this site they map to the image to 3D world and text to 3D world tools.
2. Generate. One Marble 1.1 world costs 1,500 credits, about $1.20, as of September 3, 2026; Marble 1.1 Plus adds 300 credits per extra cube if you need a larger space (Radiance Fields).
3. Inspect. Open the .spz in the free splat viewer before importing anything. Check scale, orientation and holes.
4. Export. Download .ply (lossless) and convert to .spz for the web, and the GLB mesh if you need collision or a non-splat engine path.
5. Import into your engine, following the sections below.
6. Dress and optimise. Add collision proxies, lights and gameplay geometry; reduce splat count for target hardware.

Unity

Two routes.

Splat route. Install a Gaussian splatting package from the Asset Store or GitHub; several mature ones exist and load .ply directly, and some accept .spz. Import the file as an asset, drop the generated renderer prefab into the scene, and set the layer and render order so it composites with your meshes. Splat renderers typically need the Universal or High Definition Render Pipeline; check the package’s requirements against your project.

Mesh route. Import the GLB through Unity’s glTF importer, which is built into recent versions, and treat it as a static mesh. You lose the soft look but gain colliders, lightmaps and standard materials.

A common pattern is both: splat for the far and mid environment, GLB mesh with a mesh collider for anything the player touches.

Unreal Engine

Splat route. Gaussian splatting plugins for Unreal are available on Fab and GitHub. Import the .ply, place the splat actor, and adjust sort mode and bounds. Splats in Unreal are usually rendered through a Niagara or custom pass, so expect to tune them for Lumen and Nanite scenes.

Mesh route. Import the GLB with the built-in glTF importer as a static mesh, generate simple collision, and use it like any scanned asset. For large worlds consider splitting the mesh by region before import.

Unreal users doing previs may prefer to skip the engine entirely for camera moves: when Atlas video is available, a camera path rendered by the model at 1440p is a shot you can cut against engine footage. See what the Atlas world model does.

Blender and Godot

Blender imports GLB natively. For splats, community add-ons load .ply point data and render it with geometry nodes; the results are good for look-development and camera blocking, less so for final frames. Blender is also the right place to clean and decimate the mesh export before it goes to an engine.

Godot imports GLB natively as well. Splat support exists through community add-ons and is less mature than in Unity or Unreal; the mesh route is the safe one for shipping.

Where world models fit in production

• Blockouts. Generate five variations of a level layout in an afternoon for $6, walk each in the viewer, and pick one to build on.
• Skyboxes and vistas. A panorama-driven world makes a distant backdrop that has real parallax, unlike a cubemap.
• Hero environments. Reconstruct a real location from photos, then art-direct on top of it. This is where Atlas’s few-view reconstruction matters most; see Atlas vs Marble.
• Reference and mood. Even when nothing ships, a navigable mood board beats a flat one.

Art direction on top of generated worlds

Generated worlds are a starting point, not a finished level. The productive pattern is to lock the layout from the world, then replace or overpaint what gameplay needs. Keep the splat as the visual base for walls, floors and distant detail; add authored props for anything interactive so their collision and materials are under your control; and re-light with your engine’s tools rather than fighting the splat’s baked light. When a region needs to change, regenerate the world with an adjusted prompt or reference rather than editing splats by hand, since edits to millions of Gaussians do not survive a regeneration. Version the inputs, prompts and photos, alongside the output so that a level can be rebuilt later with a better model, including Atlas once it is available.

Performance and optimisation

• Splat count is the budget. Millions of splats look great on a desktop GPU and choke a phone. Most viewers and plugins let you cap or prune; target under two million for mobile.
• Convert to .spz. Roughly a tenth of the .ply size, faster to load, and supported by Spark, the MIT-licensed three.js renderer World Labs publishes, which reads .ply, .spz, .splat, .ksplat and .sog (GitHub).
• Bake or proxy lighting. Splats carry their own lighting; mixing them with dynamic lights needs care. Match your scene’s key light to the splat’s baked light direction.
• Collision proxies. Build a simplified collision mesh from the GLB export rather than using the full mesh.
• Level of detail. Keep the splat for the near field and a low-poly mesh for far distances if your renderer supports switching.

Costs per environment

At $1 per 1,250 credits, a Marble 1.1 world is 1,500 credits, or $1.20; a 1.1 Plus world with two extra cubes is 2,100 credits, or $1.68. PLY export is free (Radiance Fields). A team generating 100 candidate environments a month spends about $120, which is less than a single day of an environment artist’s time, and the artist’s time is better spent on the one that shipped. Atlas pricing is not announced; full figures on the pricing page.

Getting started

Follow the Marble World API guide or the TypeScript quickstart to generate your first world, open it in the splat viewer, and import it with the steps above. Join the waitlist below to hear when Atlas access opens and when generation goes live on this site.