The short answer: start from the engine and asset type, not a favourite extension. FBX remains common for rigged Unity and Unreal assets. glTF/GLB is the natural starting point for Godot 4 and web runtimes. USD/USDZ fits Apple AR and composition workflows. OBJ is useful for static geometry, while STL belongs to printing rather than game delivery.
Which 3D model format should you use for games?
Use the format your target engine imports reliably with the features the asset actually needs. A static prop does not need the same format as a rigged character, and a web viewer may need a lighter answer than a cinematic Unreal scene.
| Format | Best for | What it carries | What to validate |
|---|---|---|---|
| FBX | Rigged characters and established Unity/Unreal pipelines | Mesh, skeleton, skin weights, animation and material references | Axis, scale, material remapping and version-specific import options |
| glTF / GLB | Godot 4, web runtimes and portable PBR scenes | Mesh, hierarchy, PBR materials, animation and embedded buffers | Engine-version support, texture packing and animation names |
| USD / USDZ | Apple AR, large scene composition and interchange workflows | Scene composition, hierarchy, materials and animation | Runtime support, compression and texture portability |
| OBJ | Simple geometry interchange and third-party asset handoff | Geometry and UVs, with materials referenced through MTL | Limited rig/animation support and fragile external texture links |
| STL | 3D printing, not game delivery | Triangle surface geometry without materials or scene structure | No UVs, rig, hierarchy or colour; use it only for print workflows |
Is FBX or GLB better for your game?
FBX is often the safer starting point for rigged characters in established Unity and Unreal projects. GLB is often the cleaner choice for Godot 4, web delivery and portable PBR scenes because glTF is an open interchange format with a self-contained binary container.
The useful test is not “which format has more features?” It is “which file preserves my final skeleton, clip names, material channels, UVs and scale after import?” Export one representative asset in both formats and compare the actual engine result. The Godot workflow uses GLB as its default, while the Unity and Unreal guides explain their FBX-oriented handoffs.
Which format does each game engine expect?
Engines support multiple formats, but their most practical default is influenced by importers, rigs, materials and team conventions. Use the tested path rather than treating the importer menu as a feature list.
| Destination | Practical default | Why |
|---|---|---|
| Unity | FBX, or GLB for portable static assets | Rig, animation and prefab workflows are widely understood |
| Unreal Engine | FBX for meshes and animation; USD for composition where supported | Established Static/Skeletal Mesh and scene-interchange paths |
| Godot 4 | glTF/GLB | Native scene import with hierarchy, PBR materials and animation |
| Web / three.js | glTF/GLB | Portable scene data with fewer conversion steps |
| Apple AR | USDZ | Quick Look and AR-oriented packaging |
Treat these as defaults, then confirm support in the installed engine version and on every target platform. A format that imports in the editor may still lose animation, material nodes or compression support in a packaged build. The Khronos glTF specification documents what a GLB is designed to carry; engine documentation remains the authority for what the runtime actually consumes.
What gets lost when you convert a game model?
Conversions can lose rigs, animation, blend shapes, material assignments, UV channels, custom attributes, object hierarchy and correct scale. The risk increases when moving between formats with different data models rather than re-exporting from the editable Blender source.
Prefer the source file as the conversion origin. Re-exporting the Blender scene is more predictable than chaining GLB to FBX to OBJ through unrelated tools. Follow the GLB-to-FBX, FBX-to-GLB and OBJ-to-FBX workflows when a conversion is required.
OBJ is a special case: it is useful for static geometry, but materials live in a separate MTL file and textures often remain external. STL drops even more information. If an asset needs a rig or animation, OBJ and STL are not delivery containers for that asset.
A conversion can also change apparent quality without changing the mesh. Normal-map direction, texture paths, material assignments and smooth shading can all be interpreted differently by the destination tool. A technically complete file is not approved until the visual and runtime result have been compared with the Blender source.
What should you check before exporting?
Validate the source in Blender before choosing an export button. Units, transforms and object names cause fewer problems when fixed once in the source than when overridden on every import.
- Apply transforms and set scale. Confirm one unit and remove unexpected object scale.
- Check hierarchy and pivots. Use clear parent objects and useful origins for props and modular parts.
- Inspect UVs and materials. Verify channels, texture paths and material names before export.
- Test animations. Confirm action names, frame ranges and root motion on a short representative clip.
- Import into the target engine. Inspect the mesh, materials, skeleton, collision and runtime appearance.
How do you choose a format for a mixed asset pipeline?
Standardise by asset class. A team might use FBX for Unity characters, GLB for Godot and web environment pieces, USD for Unreal composition, and STL or 3MF for print variants. That is more reliable than forcing every asset through one extension.
Document the tested defaults in the project and keep one source Blender file per asset. The game-ready model checklist covers topology, LODs and collisions that must exist before format choice can matter.
Bottom line: use FBX for many rigged engine workflows, GLB for Godot and portable web scenes, USD families where their composition or AR support is needed, and OBJ only for simple geometry interchange. Validate the actual import and keep the editable Blender source as the master.