Which 3D File Format Should I Use for My Project?

The Quick Decision Chart

For web and online 3D viewers: GLB/GLTF
For game engines (Unity, Unreal): FBX
For 3D software and maximum compatibility: OBJ
For AR on iOS devices: USDZ
For 3D printing: STL
For Blender specifically: Any of the above, plus native .blend files

That's the simple version. Now let's understand why, and the nuances of each format.

GLB / GLTF - The Web Standard

What it is: Modern web-optimized format developed by the Khronos Group (same organization behind OpenGL). GLB is the binary version (single file). GLTF is the JSON version (multiple files).

Best for: Web 3D viewers, online product visualization, AR on web browsers, any 3D content displayed in browsers or web apps.

Advantages: Small file sizes (efficient compression). Fast loading in web browsers. Supports PBR materials (physically-based rendering - modern material system). Works across all platforms (web, mobile, desktop). Becoming the industry standard for web 3D.

Limitations: Relatively new format, so older software might not support it (though modern software does). Not ideal for editing - more of a delivery format.

Use GLB when: Embedding 3D on websites, creating web-based 3D viewers, e-commerce product 3D, web AR. This is the default choice for anything web-related.

FBX - The Game Industry Standard

What it is: Autodesk's format, widely adopted in the game industry. Binary format that preserves complex data.

Best for: Unity and Unreal Engine. Game development workflows. Transferring models between 3D software (Maya, 3ds Max, Blender).

Advantages: Excellent support for animations, rigging, and complex hierarchies. Unity and Unreal have native FBX support. Preserves material information well. Industry standard in game development.

Limitations: Larger file sizes than GLB. Proprietary format (owned by Autodesk, though widely supported). Not optimized for web.

Use FBX when: Importing to Unity or Unreal. Working with rigged/animated characters. Transferring models between professional 3D software. Game development pipelines.

OBJ - The Universal Format

What it is: Old-school format (from the 1980s) that just describes geometry. Simple, text-based, universally compatible.

Best for: Maximum compatibility. Sharing models between different software. Simple models that don't need complex features.

Advantages: Every 3D software can open OBJ. Simple and reliable. Materials stored in separate MTL file (plain text, easy to understand). Good for editing in multiple programs.

Limitations: No animation support. No modern PBR material systems (uses older Phong shading). Larger file sizes. Materials/textures aren't embedded (separate files).

Use OBJ when: You need to open a model in various software. Sharing models with people using unknown software. Archive/storage of 3D data. Simple static models without animation.

USDZ - Apple's AR Format

What it is: Apple's proprietary format for AR (augmented reality). Based on Pixar's Universal Scene Description (USD).

Best for: AR Quick Look on iOS devices. iPhone and iPad AR experiences. Apple ecosystem AR apps.

Advantages: Works seamlessly with iOS AR features. Optimized for mobile performance. Supports PBR materials. Single file contains all assets (geometry, textures, etc.).

Limitations: iOS-specific (though Android has some support). Not many tools create USDZ directly (usually convert from other formats). Primarily a delivery format, not for editing.

Use USDZ when: Creating AR experiences for iPhone/iPad. Apple AR Quick Look integration. iOS-focused AR apps. E-commerce product AR on iOS.

STL - The 3D Printing Format

What it is: Simple format that describes surface geometry only. Developed for 3D printing (stereolithography).

Best for: 3D printing. CNC machining. Any manufacturing process that needs surface geometry.

Advantages: Every 3D printer software accepts STL. Simple format - just triangles describing surface. Small file sizes for simple geometry.

Limitations: No color, no textures, no materials - just geometry. No internal structure information. Not suitable for rendering or visualization (no appearance data).

Use STL when: 3D printing models. Manufacturing and prototyping. Situations where only the shape matters, not appearance.

DAE (Collada) - The Open Standard

What it is: Open-source XML-based format. Designed as a universal interchange format between 3D software.

Best for: Sharing between different 3D applications. Some game engines (older Unity versions preferred it). Open-source workflows.

Advantages: Open standard (not proprietary). Good cross-software compatibility. Supports animations and complex scenes.

Limitations: Being replaced by GLB/GLTF for most uses. XML format is verbose (large files). Less commonly used than it used to be.

Use DAE when: Specific software requires it. Open-source 3D workflows. Legacy compatibility needs.

Conversion Between Formats

You're not locked into one format. Most 3D software can convert between formats. Blender (free) can open and export all common formats. Online converters also exist.

Common workflow: AI generates model → download in your preferred format, or download OBJ → convert to whatever you need using Blender or online tool.

Some conversions are lossless (no quality loss), others lose information. For example:

FBX to GLB: Usually good, materials translate well
GLB to OBJ: Lose some material information
FBX to STL: Lose all materials/textures, keep only geometry
OBJ to FBX: Geometry preserved, materials might need adjustment

Practical Use Cases

E-commerce website with 3D product viewers: Use GLB. Fast loading, good quality, works in all browsers.

Unity game with 100 props: Use FBX. Unity's native format, handles all your assets smoothly.

Sharing 3D models with a client (who might use any software): Use OBJ. Universal compatibility ensures they can open it.

AR app for iPhone showing furniture in customers' rooms: Use USDZ. Optimized for iOS AR.

3D printing custom figurines: Use STL. Standard format for all 3D printers.

Architectural visualization (rendering in various software): Use FBX or OBJ. Good compatibility with rendering software.

File Size Considerations

Same model in different formats has different file sizes:

GLB: Most efficient, smallest file (good compression)
FBX: Medium size
OBJ: Large (uncompressed, plus separate texture files)
USDZ: Medium to large
STL: Depends on geometry complexity

For web delivery, file size matters (affects loading speed). For local use (game engines, 3D software), file size is less critical.

Future-Proofing

If you're archiving 3D models for long-term storage, OBJ is safest. It's been around for 40 years and isn't going away. Simple format means future software will always be able to read it.

For current work, GLB and FBX are the modern standards and will be supported for the foreseeable future.

What About Native Formats?

3D software has native formats (.blend for Blender, .max for 3ds Max, .ma/.mb for Maya). These preserve everything about your scene - full editing capabilities, software-specific features.

Use native formats for active projects you're working on. Use export formats (GLB, FBX, OBJ) for delivery and sharing.

Quick Troubleshooting

Model won't import to Unity/Unreal: Try FBX format. These engines prefer FBX.

3D viewer on website loads slowly: Use GLB and compress it. Consider reducing texture resolution.

Materials look wrong after import: Different formats handle materials differently. You might need to reassign materials in your target software.

File is too large: Convert to GLB (good compression), or reduce texture resolution, or decimate geometry.

Many platforms like 3DAI Studio let you download models in multiple formats, so you can experiment and see which works best for your specific workflow and requirements.