[x3d-public] wondering about glTF and Draco relationship

[Don Brutzman]

Thanks for this thorough review, very helpful for building understanding and considering future work.

On 4/26/2021 7:52 AM, Leonard Daly wrote:
> Below is my response reviewed by 3D Formats WG. Don's questions were pulled out and included here in green.
> 
> 
>  > Question about Draco: thought it was usable as a preprocessor for glTF files that could produce .glb files, but is that incorrect?
> 
> Draco is compatible with glTF. There is an extension (Announcement: https://www.khronos.org/news/press/khronos-announces-gltf-geometry-compression-extension-google-draco; Specification: https://github.com/KhronosGroup/glTF/blob/master/extensions/2.0/Khronos/KHR_draco_mesh_compression/README.md) that is required for this (Draco) to work.
> 
> 
>  > If Draco is compatible with glTF do we need to mention it (as an optional perhaps) in X3D4?
>  > If Draco-compressed files are not compatible with glTF files, what is the relationship?  What are their intentions?
> 
> Depends on what level of glTF support Web3D wishes to impose on X3D. Draco support is an extension to the core glTF V2.0 specification. Draco is fundamentally a memory-based operation. The GitHub package from Google includes encoders and decoders. The glTF extension handles the Draco Bitstream (https://google.github.io/draco/spec/)
> 
> 
>  > Near-term impact: do we need to add any comments in X3D4 submission to ISO ballot (deadline 5 May)?
> 
> That is a Web3D issue.
> 
> 
>  > Long-term impact: can we encourage use of Draco-processed loading of glTF models, or will we need to wait until revisiting X3D Compressed Binary Encoding?
> 
> The Asset Creation Guidelines (https://github.com/KhronosGroup/3DC-Asset-Creation/blob/main/asset-creation-guidelines/RealtimeAssetCreationGuidelines.md*) *from the 3D Commerce WG of Khronos recommends using Draco compression for geometry and use of KTX images (https://www.khronos.org/ktx/) for image transmission/GPU use. It is up to Web3D Consortium to determine how X3D wishes to use them.
> 
> Leonard Daly
> 
> 
> 
> On 4/22/2021 8:23 AM, Don Brutzman wrote:
>> Hello Web3D-Khronos Liaison Experts!  Here are some public questions for you, originating in our CAD Design Printing Scanning and X3D Working Groups.
>>
>> Question about Draco: thought it was usable as a preprocessor for glTF files that could produce .glb files, but is that incorrect?
>>
>> * https://google.github.io/draco
>>
>> "Draco is an open-source library for compressing and decompressing 3D geometric meshes and point clouds. It is intended to improve the storage and transmission of 3D graphics."
>>
>> If Draco is compatible with glTF do we need to mention it (as an optional perhaps) in X3D4?
>>
>> If Draco-compressed files are not compatible with glTF files, what is the relationship?  What are their intentions?
>>
>> Near-term impact: do we need to add any comments in X3D4 submission to ISO ballot (deadline 5 May)?
>>
>> Long-term impact: can we encourage use of Draco-processed loading of glTF models, or will we need to wait until revisiting X3D Compressed Binary Encoding?
>>
>> Thanks in advance for all inquiry and insight.
>>
>> all the best, Don
> 
> -- 
> *Leonard Daly*
> 3D Systems & Cloud Consultant
> LA ACM SIGGRAPH Past Chair
> President, Daly Realism - /Creating the Future/
> 
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all the best, Don
-- 
Don Brutzman  Naval Postgraduate School, Code USW/Br       brutzman at nps.edu
Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA   +1.831.656.2149
X3D graphics, virtual worlds, navy robotics http://faculty.nps.edu/brutzman