3D file support

3D file support

Marso Studio accepts GLB, USD and FBX uploads. GLB and USD are the most mature paths today. FBX is the newest format we accept and carries the highest risk of import or generation errors.

Every format needs an image-based base-colour texture mapped to the geometry. Vertex colours are not textures, and assets coloured with vertex data alone will be rejected.

Requirements by format

GLB (recommended)

GLB upload	Accepted?
Textures embedded in the file	✅
A base-colour texture on every material	✅
Textures referenced externally (URI or file path)	❌
A material with no texture	❌

GLB has the strictest texture rules — see What gets a GLB rejected for the detail.

USD

Package as .usdz with geometry and a base-colour texture.

USD upload	Accepted?
Textures embedded or referenced inside the package — we re-resolve them	✅
Geometry with no base-colour texture	❌

FBX

Either embed the textures inside the .fbx, or zip the .fbx together with its texture files.

FBX upload	Accepted?
Textures embedded in the .fbx, or zipped alongside it	✅
Base-colour map named by convention (see below)	✅
A zip that doesn't follow the naming convention	❌
External textures not bundled in the zip	❌

Base-colour naming convention: name the map game.color.png, color.png, albedo.png, basecolor.png, or base_color.png.

Supported model features

These all work, across your uploads:

Feature	Supported?	What it means
Multi-mesh	✅	Multiple separate objects in one file (e.g. a table and a chair).
Multi-material	✅	Different parts of your model can use different materials (e.g. one shiny, one matte).
Texture atlasing	✅	Pack multiple materials' textures into one image — as long as each material's UVs occupy a distinct region of it.
Adjacent UV regions	✅	Two materials' UV regions can touch along a shared edge (e.g. left half and right half) — touching is not overlapping.

What gets a GLB rejected

GLB uploads must be fully self-contained. We reject:

Issue	Why we reject it
External textures	The GLB must embed every texture. GLBs that reference textures by external URL or filename are rejected.
Untextured materials	Every material must have at least one texture (base colour, normal, metallic-roughness, occlusion or emissive).
Broken texture references	Texture slots pointing to a missing texture, missing image, or empty image data are rejected.
A separate texture file alongside the GLB	Embedded textures are the source of truth — sending a GLB plus a loose texture file is rejected.

Good to know

Allowed by the validator today, but worth watching:

• Tiled / out-of-[0,1] UVs. UVs are read as raw values, not wrapped into the [0,1] square. A material whose UVs run 0–5 (to tile a texture) is treated as occupying that whole 0–5 range and will very likely collide with another material — so tiling-style UVs are effectively unsupported.

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File requirements are only half the story — getting a good result also depends on the kind of asset you bring. See Sourcing & preparing assets.