[x3d-public] both X3DOM and X_ITE.

[Joseph D Williams]

From: Andreas Plesch
Sent: Monday, May 28, 2018 11:47 AM
To: Joseph D Williams
Cc: John Carlson; x3dom mlist; X3D Graphics public mailing list
Subject: Re: both X3DOM and X_ITE.

➢ There just does not seem a lot of demand or requests by users or
customers. Of course, this may be a chicken and egg problem.

And, that if you hae soething that works, like contact and instant, maybe you don’t need to complain. 

➢ Contributions to x3dom or x_ite are always welcome, in any case.

Great a contribution to either is a contribution to X3D. 

➢ For x3dom, my interest would be probably the glTF angle. glTF has
character animation. Here is an example:
https://www.donmccurdy.com/2017/11/06/creating-animated-gltf-characters-with-mixamo-and-blender/

Great, I will look. The basic x3d hanim skeleton, bindings, animations, and geometries can be stored in gltf. I hope I can look back in the hanim archives to see a comparison I did. No doubt gltf can transport the good stuff with the only problem that gltf uses unit quats instead of axis-angle.  

➢ The best explanation, apart from studying glTF loaders, is apparently
in this figure, sorry about that:
https://raw.githubusercontent.com/KhronosGroup/glTF/master/specification/2.0/figures/gltfOverview-2.0.0a.png

OK, I will look for more recent info, but I don’t think anything in this has changed. Structure and data – names may be different but the data and its application is the same. Now I know there may be some new tech but for the basics stuf, not much has changed in the last 20 years since hanim was specified. 

➢ There is probably a lot of overlap between glTF and HAnim and it would
be important to understand how both relate to each other to be able to
support both. I think Leonard tried to tackle this but focusing
specifically on glTF-HAnim may be constructive. For example, a
translation of a simple glTF character to an HAnim humanoid would be a
good first step.

A better first step would be to transcode an HAnim humanoid into gltf and back again. From what I saw it would work. After all, it is all the same structure and same data. I was going to work on the Boxman and the JoeKick models in the x3d hanim example archives

➢ A functional, minimal subset of HAnim of nodes and/or a Proto-based
implementation of the nodes would also help implementers.

Of course we have the proto-based nodes for HAnim where the geometries are children of Segments (bones) and we animate the skeleton. A prototype for seamless skin animation is Boxman in x3d hanim archives - it needs a fancy script to move skin. Since there are no other features of x3d that approximate the way skin is animated, there are no scriptless prototypes. 

➢ A main challenge will be probably the requirement to have vertex
geometry manipulation in a shader on the GPU. This is done only for
displacement textures of a CommonSurfaceShader node currently in
x3dom.

Yes, we need to control individual ‘skin’ vertices according to a simple weighting algorithm depending upon rotation of one or more joints. That has been a problem, yet it is so basic, that and morph shape, that we should have both features outside the Humanoid container. 

If anyone wants to learn character animation, anything you learn about x3d hanim will not be a waste of time. X3d hanim still documents an industry standard approach where inputs were taken from all major toolmakers because strangely, even back in the late 1990’s there was great input from users to the biggies that they had to allow data to be exported and transported between applications. Only the names were changed to prevent favoritism and preserve innocence – ooh, and to bring the secretive data structures and bindings out into the open. . 


➢ -Andreas

Thanks and Best, 
Joe



On Mon, May 28, 2018 at 10:42 AM, Joseph D Williams
<joedwil at earthlink.net> wrote:
>> both X3DOM and X_ITE …
>
>
>
> The discussions about both X3DOM and X_ITE are, to me, missing a very
> important feature. Neither of these tools can do HAnim skeleton controlled
> deformable skin. This is a very important feature, lending itself to many
> important applications in addition to HAnim. There have been several
> discussions about the hanim joint(s) to deformable skin bindings and as far
> as I have seen, there is no doubt that the way x3d specifies the basic, most
> simple, and most transportable technique to achieve the result. So, as the
> HAnim standard takes the next step, why not move a bit toward implementing
> this important capability in your browsers. BSContact does it, I think
> Instant does it mostly but x3dom and x_ite don’t.
>
>
>
> Thanks and Best,
>
> Joe
>
>
>
>



-- 
Andreas Plesch
Waltham, MA 02453

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