glTF Working Group Meeting 2021-11-11

[humbletim]

Agenda

• Update on Implementation Status
  • Spec
    • Need to add markdown explainer
    • Publish blog post advertising the OMI_audio_emitter ecosystem
  • omi-gltf-samples-repo
    • should we set this up?
    • refs:
      • https://github.com/KhronosGroup/glTF-Sample-Models
      • jin's comments re: samples repo (discord message: https://discord.com/channels/770382203782692945/835369558541467668/907996893039177739)
  • three-omi https://github.com/omigroup/three-omi
  • Third Room Feat/Audio Emitter matrix-org/thirdroom#17
  • Unity https://github.com/omigroup/glTFast-demo
    • VRChat
    • Altspace
  • Godot
• Next extensions
  • When is it appropriate to start working on these?
  • What resources would make this process easier?
    • File issues for various resources needed
  • What proposals would people like to see most?
• Introduction Kit for using OMI Audio Emitter
  • ultra simple first impression self-contained .gltf example? (for those wanting a quick glimpse at what integration would be up against)
  • links to resources for integrating
  • links to sample files to test integration with
  • ...

Parking Lot

• Neos
• Hubs (OMI Audio Emitter Hubs-Foundation/hubs#4741
• Stereo Kit

[fire]

1. Mike | Icosa worked on the json parser on Unity.

[fire]

I have done some work on the MaterialX extension.

1. draft https://github.com/fire/glTF/blob/materialx/extensions/2.0/Vendor/OMI_texture_mtlx/README.md
2. https://github.com/fire/MaterialX/tree/gltf

[mikeskydev]

I have been comparing different JSON loaders inside Unity. @atteneder mentioned performance and size concerns for Newtonsoft.Json, which I have confirmed in testing.

I downloaded the NuGet package for System.Json, which is a platform extension package https://www.nuget.org/packages/System.Json. It has a similar parse speed based on my testing, but System.Json is a much smaller package compared to Newtonsoft.Json. System.Json doesn't need a struct passed to it, and you can query the parsed object for any arbitrary key: data["node"] or check if a node exists: ContainsKey("node")

UniVRM's parser, called UniJson, came in slightly faster than both. https://github.com/vrm-c/UniVRM/tree/master/Assets/UniGLTF/Runtime/UniJSON

See below for speed comparison on a fairly complex glTF.

I also want to investigate new .NET 5 (.NET6?) replacement for System.Json, but I'm not sure how compatible the latter is with Unity due to it's .NET version.

[lyuma]

Godot status:
Godot's proposed GLTF extension api ( godotengine/godot-proposals#3305 ) has not been finalized / approved yet.
We could move forward with an importer more like the VRM importer. Question: does Godot 3.4 / 4.0 allow overriding the built-in GLTF import?

[mrmetaverse]

Suggestions per our conversation: Maybe make an empty node with a audio emitter attached to it with a default sound. Maybe also make an example object, like a sword, and give it a metallic sound. Or a cat glb with a built in purr sound.