[x3d-public] PBR in X3D4 using glTF and import as Inline

[Joseph D Williams]

TODO. Work in-progress.
• into TimeSensor + CoordinateInterpolator. This means that at runtime, we just do CoordinateInterpolator animation, not skinned mesh animation anymore. This is not the final solution. Although in practice it works very nicely:

… For making videos

➢ Still, there are some big drawbacks:
• You can no longer transform bones (just Transform nodes) to modify skin at runtime 
So, the gltf folks aren’t telling us how they recommend to setup a gltf file for realtime skeleton-driven skin animations? They are only storing data showing something that allows a fixed interpolator displacements for the skin?  Not surprising because the real animations hidden in the delivery of this type of interpolated skin gltf is some of the hardest to develop and stuff most wanted to keep hidden. 
I hope all can sidestep this skeleton-driven skin animation deficit of the current gltf and get all browsers doing Hanim. Actual implementation of animation technique designed to produce realltime anytime interactive animation of shapes and skins. 
➢ The memory use of long-running animation is significant
Lots better than just outputting complete frames of pixels for the video, which was once the best we could get. 
➢ In CGE we have also implemented H-Anim, which is X3D way of doing skinned mesh animation.
I think it is just the x3d way of encoding skeleton-driven skin animations as proven by years of implementations driving this technique for realtime, and really, also the Displacer animations. When this is mastered, I think it will give clues to how to encode a gltf example humanoid. For example, when storing a file for a humanoid using gltf, it might include the matrix at issue that was computed by the author tool and used directly by the runtime tool. Otherwise, doing the level2 skeleton-driven skin animation has always been heavy learning for every x3d browser maker willing to take the step. 
To me this also shows that we need to turn this around a bit an develop some gltf tuned for x3d. How much easier it is to read and organize user code when I can just reference a json file to hold data and thus clean up my listing. 
➢ If any major 3D authoring software becomes capable of exporting to H-Anim,
BSContact? VIZX3D, xite? 3dsmax? You mean if any major authoring software extends themselves from making videos and moves towards realtime interactive live scenegraph simulations?
Thanks,, 
Joe




From: Michalis Kamburelis
Sent: Wednesday, March 30, 2022 4:19 PM
To: Joseph D Williams
Cc: X3D Graphics public mailing list
Subject: Re: [x3d-public] PBR in X3D4 using glTF and import as Inline

This is all documented on
https://github.com/michaliskambi/x3d-tests/wiki/Converting-glTF-to-X3D
.

It is linked from the bottom of
https://github.com/michaliskambi/x3d-tests/wiki/2022-Talk-About-X3D-PBR-glTF
:)

Regards,
Michalis

czw., 31 mar 2022 o 00:05 Joseph D Williams <joedwil at earthlink.net> napisał(a):
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> HI All, Thanks Michalis, for the show. PBR stuff very impressive and looking usable. For the gltf files imported as Inlines, I hope you will show more about how you  extract the data from tha gltf node file to create the model as an Inline. Which fields of the gltf node file are used to create what at least must be a Shape with some sort of geometry and colors? Where does the mesh and color come from and how to use this to create the vizualized model? Also the animations. How to generate the behavior model from what is in the gltf file(s)?
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> Thanks Again for the presentation.
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> Joe
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