FBX vs OBJ vs GLB vs USDZ: 3D File Formats Explained for Game Developers
What each major 3D file format is actually for — FBX, OBJ, GLTF/GLB, USDZ, STL, DAE — which engines want them, and which to keep in your asset library.
Download assets from five marketplaces and you'll end up with five different file formats. They are not interchangeable, and knowing what each one is for saves you broken imports, missing textures, and wasted disk space. Here's the working knowledge, format by format.
FBX — the game-industry workhorse
Autodesk's FBX is the de facto interchange format for game development. It carries meshes, materials, skeletons, skinning, and animation, and every major engine and DCC tool imports it. Most paid asset packs ship FBX first.
- Strengths: animation + rig support, universal engine compatibility (Unreal and Unity both prefer it)
- Weaknesses: proprietary and versioned — old exports can misbehave; textures are usually referenced, not embedded, so moving an FBX without its texture folder breaks materials
OBJ — the simple veteran
OBJ is a plain-text format from the 1990s that stores geometry and UVs, with materials in a companion .mtl file. No rigs, no animation — just the mesh.
- Strengths: opens literally everywhere, human readable, great for static props and scans
- Weaknesses: the
.mtl+ texture files must travel with it; large meshes get bulky
GLTF / GLB — the modern web-native standard
GLTF (and its single-file binary form, GLB) is the Khronos Group's open standard, designed for fast runtime loading with PBR materials built in. GLB embeds everything — geometry, materials, textures — in one file, which makes it the most portable format in the list.
- Strengths: self-contained, open standard, PBR by default, tiny and fast; the standard for web/AR and increasingly common on marketplaces like Sketchfab
- Weaknesses: engine import support is good but newer than FBX; complex rigs and DCC round-trips are weaker
USDZ — Apple's scene format
USDZ packages Pixar's USD scene description into a single file. It's Apple's native 3D format — Quick Look, ARKit, and SceneKit all speak it fluently, and it's the only format macOS will preview out of the box with a spacebar press.
- Strengths: first-class on every Apple platform; strong scene-composition features inherited from USD
- Weaknesses: limited support outside the Apple ecosystem; most game marketplaces don't ship it
STL and DAE — the specialists
STL is pure geometry — no UVs, no materials — built for 3D printing. Useful if you scan or print; useless for textured game art. DAE (Collada) is an older open XML interchange format; you'll still meet it in legacy packs and some marketplace downloads, and SceneKit reads it natively.
Which files should you keep?
| You're doing… | Keep |
|---|---|
| Unreal / Unity game work | FBX (+ its texture folder, always) |
| Web, AR, or quick sharing | GLB |
| Static props, scans, kitbash | OBJ or GLB |
| Apple-platform / visionOS work | USDZ |
| 3D printing | STL |
When a marketplace offers multiple formats, grab FBX and GLB if storage allows: FBX for the engine, GLB as the portable, self-contained reference copy.
The real problem: browsing a mixed-format library
In practice your library will contain all of these at once, and most tools only preview some of them. LocalFab was built for exactly this mess: it indexes OBJ, FBX, GLTF, GLB, STL, DAE, and USDZ side by side, previews them all in one native viewport (converting FBX/GLB behind the scenes and caching the result), and shows per-mesh data like poly counts and texture references so you can compare across formats. If that sounds like your drive, start with our library organization guide — or get early access.