glTFast Documentation

glTFast enables use of glTF™ (GL Transmission Format) asset files in Unity.

It focuses on speed, memory efficiency and a small build footprint while also providing:

• 100% glTF 2.0 specification compliance
• Ease of use
• Robustness and Stability
• Customization and extensibility for advanced users

Features

glTFast supports the full glTF 2.0 specification and many extensions. It works with Universal, High Definition and the Built-In Render Pipelines on all platforms.

See the comprehensive list of supported features and extensions.

Workflows

There are four use-cases for glTF within Unity

• Import
  • Runtime Import/Loading in games/applications
  • Editor Import (i.e. import assets at design-time)
• Export
  • Runtime Export (save and share dynamic, user-generated 3D content)
  • Editor Export (Unity as glTF authoring tool)

Runtime Import/Loading

Load and instantiate glTF files at runtime in your game/application via Script or the GltfAsset component.

Benefits of Runtime Import

• Efficiently load dynamic and/or third-party assets
  • Make use of state-of-the art mesh and texture compression methods, like KTX/Basis Universal, Draco and meshoptimizer.
• No need to re-build your application or Asset Bundles upon Unity version upgrades

glTF was specifically designed for vendor-independent transmission and runtime loading and naturally plays its strengths there.

Editor Import (Design-Time)

Although primarily designed for runtime, glTF's effective design and its modern, physically-based material definition make it great for most simple DCC (digital content creation) interchange as well.

Read about usage below.

Benefits of Editor Import

• Less friction between artists and developers due to glTF as standardized interface
  • Example: artists don't need to know or follow Unity shader specific conventions and thus developers don't need to instruct them
• Enables adding rich interaction and behaviour to assets (e.g. custom scripts or animation controllers)
• In conjunction with Editor Export, Unity becomes a complete tool for re-mixing 3D content
• ¹Use default Lit (URP/HDRP) or Standard (Built-in render pipeline) materials

¹: Not yet supported (see issue)

Editor Export

Use the Unity Editor as an authoring tool and export your scenes and GameObjects as glTFs.

Note: This feature is experimental

Use-cases for Editor Export

• Unity runtime loading
• Social media sharing
• Use within the vast glTF eco system, like third-party viewers or asset pipelines
• Archiving

Runtime Export

Allows your Unity-powered application/game to export scenes/GameObjects to glTF at runtime.

Use-cases for Runtime Export

• Preserve dynamic, user-generated 3D content
  • Create metaverse-ready 3D snapshots of a current state / game action
  • 3D product configurations (e-commerce)
• Build high level editing and authoring tools with Unity
• Social media sharing

Note: This feature is coming soon (see issue)