[x3d-public] Purpose of X3Dng -- Animation (of humanoid models)

[yottzumm at gmail.com]

Like  ExternProtoDeclare/ProtoDeclare/ProtoInterface/ProtoBody which can be used with ProtoInstances.  Sorry for wrong terminology.

John

Sent from Mail for Windows 10

From: Michael Aratow
Sent: Tuesday, October 25, 2016 10:20 PM
To: x3d-public at web3d.org
Subject: Re: [x3d-public] Purpose of X3Dng -- Animation (of humanoid models)

Hey John
I am from the Medical Working Group and a practicing physician.  Use cases for healthcare should be created for both HAnim and X3D as it is a significant vertical market which we say these standards address.  
I am not exactly sure what you mean by a prototype for each surgery.
Thanks,
Mike


On 10/24/16 1:34 AM, yottzumm at gmail.com wrote:
The only thing that I can think of that isn’t more animation based (abstract biological processes) and is more human based is surgeries or injuries.  Should there be a place in the X3D or H-Anim examples for surgeries?  A prototype for each surgery perhaps?   How do doctors deal with unusual circumstances?  Can someone forward this to the Medical Working Group (I don’t have their address handy).  Can we digitally sign the examples so we know they haven’t been corrupted?
 
John
 
Sent from Mail for Windows 10
 
From: Leonard Daly
Sent: Sunday, October 23, 2016 11:43 PM
To: yottzumm at gmail.com; x3d-public at web3d.org; Human Animation working group
Subject: Re: [x3d-public] Purpose of X3Dng -- Animation (of humanoid models)
 
On 10/23/2016 8:30 PM, yottzumm at gmail.com wrote:
Leonard,
 
I think you wanted to say for your last sentence: “If X3Dng joint animation and skin deformation was taken, perhaps wholesale, from H-Anim, what would be left in H-Anim?”
 
But you can probably word-craft better than I can.  Have another go at it if you like.

John,

Thanks for pointing this out. I am not too particular to get the discussion going. What you said is correct, but I did want to give the opportunity to include other material that might better fit the mission of H-Anim. I do not know what that might be, nor do I wish to presume anything about that mission. I did intend it to be an open-ended question, though I could have improved the wording.


Leonard Daly





 
John
 
Sent from Mail for Windows 10
 
From: Leonard Daly
Sent: Sunday, October 23, 2016 11:22 PM
To: x3d-public at web3d.org; Human Animation working group
Subject: Re: [x3d-public] Purpose of X3Dng -- Animation (of humanoid models)
 
I want to point out that my posting on X3Dng Animation [http://realism.com/blog/purpose-x3d-animation] (BTW, ng == next generation) is not necessarily for characters - human, humanoid, or animal. It is a means of animation that is in standard use in the animation industry. It is frequently applied to characters, but that is not the only possible target of the animation. 

This method of animation is not "fool-proof" - there are some edge cases that cause problems -- for example a rotation of pi radians on a joint that can twist causes the skin to "candy-wrap". See http://www.cs.cmu.edu/~yaser/Lecture-9-Skinning%20and%20Body%20Representations.pdf, pages 27-34 for a visual and technical description of the issue. The charts also provide a lot of the mathematical framework that Don discusses below including motion capture.

So I'll ask my question again, if X3Dng includes joint animation with skin deformation at a profile that is generally used (e.g., Immersive or less); what should the H-Anim specification cover? I am not trying to imply that H-Anim should not exist, but a big chunk of the document does discuss joint animation with skin deformation. If that capability were part of the X3D specification, would it need to be repeated in H-Anim? (If so, why?). If it was removed, what would be the appropriate material to include in the document?


Leonard Daly


[cc: h-anim] 

Summary: a lot of capability is steadily adding up with H-Anim, and beginning to overlap with Medical and CAD. 

Great observations below, Joe and Michalis!  8)  Thank you.  Here are some reactions. 

We have had a lot of work to achieve progress towards X3D version 4.  (Don't know what the subject-line "X3Dng" refers to.)  Recent progress is confirming that the work on X3D Object Model has been fundamentally important as a way to ensure that the entire X3D scene graph is consistent and coherent across every file encoding and every programming language binding.  So we are really building for scalable, repeatable success. 

Observation: SFRotation axis-angle representation is mathematically equivalent to quaternions, so there is no conversion issue there.  Matrix rotations are also almost-fully equivalent with only a few edge-case anomalies like the possibility of exceptions when computing inverses.  So mapping to different forms of rotations is not particularly difficult when using X3D SFRotation, it just takes close attention to detail. (One virtue of programming, even when challenging, is that You Only Have To Get It Right Once.) 

Personally, am hoping to get back to work on the BVH-mocap-to-X3D-interpolators converter code before the end of the year.  Goal is to have this open source Java running and producing X3D animations, just like Suwon University's C++ code did for their H-Anim Music Video competition.  That should establish a baseline of 2 mocap-related implementations that can help us continue to improve. 

    https://svn.code.sf.net/p/x3d/code/www.web3d.org/x3d/tools/X3dEdit3.3/X3D/src/org/web3d/x3d/hanim/bvh/ 
    BvhSkeletonParameters.java 
    Hierarchy.java 
    Joint.java 
    Motion.java 

All of the recent review activity and interest during the H-Anim specifications review is certainly a wonderful development.  When all of the other H-Anim specification comments are assembled from participating ISO national standards bodies, we can plan on an Specification Editors Meeting to consider issues and best plans for resolutions.  Meanwhile, as time permits, the H-Anim and X3D Working Groups can continue looking at the baseline mantis issues list to prepare potential solutions. 

I also agree that the path to success lies through implementation and evaluation.  As we keep building examples, and implementing conversions, and adding tool support, am expecting the differences between different approaches will appear simpler, clearer, more adaptable, and easier to support.  Similarly, it makes no sense to change what we have in H-Anim until we have direct evidence of problems or how to accomplish potential improvements. 

Current H-Anim example models: 

    http://www.web3d.org/x3d/content/examples/Basic/HumanoidAnimation 

Regarding importance of H-Anim tutorials: another point well taken.  Here is one with 97 slides (second half includes slides + annotation notes).  Questions, corrections and suggestions for improvement welcome. 

    http://x3dgraphics.com/slidesets/X3dForAdvancedModeling/HumanoidAnimation.pdf 

Does it make sense to add adaptation/conversion of Blender character animations into H-Anim models as a goal?  Blender does have excellent general support for X3D export/import (on its top-level File menu).  If so, we could add it to: 

    web3D.org > PARTICIPATE > Projects Wish List 
    http://www.web3d.org/projects/wish-list 

Perhaps someone wants to look at Cobweb source and help out with adding support for H-Anim nodes.  Not so hard, the pattern is somewhat similar to CAD nodes, already implemented in X3DOM; yet another open-source example implementation is available as X3D prototypes (no Script needed) at: 

    X3D Example Archives: Basic, Humanoid Animation, HAnim Prototypes 
    http://www.web3d.org/x3d/content/examples/Basic/HumanoidAnimation/HAnimPrototypesIndex.html 

    Cobweb Supported Components 
    http://titania.create3000.de/cobweb/#c426 

Looking further ahead.  There is one more clarion priority for H-Anim progress: modeling human joints, bones, skin and motions at a resolution suitable for medical applications and electronic health records.  Alignment of DICOM-standard medical imagery as X3D volume presentations is another emerging major asset.  Common interest with CAD group in metadata annotations, 3D printed parts (splints, prostheses, devices) and 3D scanning is also truly compelling.  The CAD and medical workshops at the Web3D 2016 Conference in Anaheim a few months back showed that much is possible.  Early-exemplar case study: 

    3D Printed Heart for Printed Preoperative Planning 
    Two views of a printed heart from MRI data 
    http://www.web3d.org/example/3d-printed-heart 

Assembled and aligned together, with working tools + repeatable workflows + validation of correctness, the X3D family of technologies holds tremendous promise to broadly improve medical understanding and communication. 

All of this technical scrutiny is super valuable.  Having a constructive community is so valuable - we avoid blunders and steadily build shared understanding. 

Onward we go, step by step! Looking forward to continuing progress together. 


On 10/21/2016 5:06 PM, Joe D Williams wrote: 

It would be fantastic if e.g. Blender armature animation was exported 
to X3D. It is already possible, as H-Anim supports the necessary 
features --- what is miss is the actual code on the side of Blender 
(Python) exporter to X3D. 

Good idea, perhaps if the Blender animation data exists so it can be made to work in interpolators. 
Sometimes the export of animation intended for rendering to film or video is just a list of completely rendered frames rather than an actual realtime animation style. 

If the data exists to export keyframe keys and keyvalues, then the rotations and translations should be easy to get. In an 'old style' armature they were not interested in joint rotation but depended upon bone orientation. That is OK because the purpose was to pose the artatmure for the next frame, not to worry about interpolation since they knew the target frame intervals. That is OK, bone orientation and joint rotation is the same. 

Another detail is that the joint animation data may be in unit quaternions, which is actually most likely since it is the preferred form in collada and glTF.  Or, the data may use euler-type angles (x-y-z) that need to be converted to x3d axis-angle which can be straightforward. 

That is what Part 2 of new HAnim is about, how to import mocap and other types of animation data. First you consider the capture skeleton, then you model it to a model of an HAnim 'standard' playback skeleton, convert the keyvalues as required, create the positon and orientation interpolators, then run the thing. Everyone's comments on this Part 2 is also appreciated. 

I don't think we want to also cover the idea of no interps, just itty through the mocap keyvalues for video or film fixed frame interval rendering and capture. X3D's target is realtime or anytime and everytime. Of course you also make video or film using X3D. Same for 'general' coverage of this anmation technology. Of course you can do anything you want. You don't need study HAnim very long until you learn that yes, you can define your own joint hierarchy, use any names you wish, and attach any kind of geometry and sensors you wish. If you want to do different shaped skin, then fine. Finally, if you understand the skelton setup, you can just fly them joints around to achieve most any animations possible with your model. You can easily adjust animations with a keyboard, a text editor, and an X3D player. 

Whatever you do, there are the same rules. Similar skeletons with similar initial pose can exchange skeletal animations. That is the most important point of this entire effort. Exchange skins when skeleton joint hierarchy, skin vertex count, order of appearance in the user code, and feature point relationships are the same. Sure we could tell that story in a series of tutorials but this is a spec. Maybe not this example, but the spec does not always need to spell out the history or details that would be obvious to an expert in the field, just the bare implementation requirements. 

Again, capabilities in this spec can describe any skeleton but I think we want to target something concrete. Something that can have a set of reference inputs and a set of reference outputs. Finally, we want a 'standard' set of example animations that work with each of the 'standard' LOA definitions. 

For this spec effort, the most important thing is that Implementors get it right. If the implementation can deliver a 'standard' humanoid that uses 'standard' animations, then we have something. If the implemetation gets it right, then the users can get most anything out of it they want. So that is why the HAnim spec targets the 'standard' animatable humanoid. 

When we discuss general X3D animation facilities, of which there are many, then that is the job of a set of tutorials. Please recall that the spec is addressing Implementors, and technicallly-oriented users, not the general user. Usually the spec will fail when it wanders into general tutorials aimed at general users. 

Still, the idea of bringing something like the HAnim DIsplacer up into the same bag of tools as other styles and types of interpolators would be a fine idea. I think that might be what Leonard was mentioning when he said there are other more basic tools than joint-actuated mesh deformation. It is easy to recognize the Displacer as a basic mesh animation tool that would be encountered in early animation lessons. 

Thanks and Best, 
Joe 


----- Original Message ----- From: "Michalis Kamburelis" <michalis.kambi at gmail.com> 
To: "Leonard Daly" <Leonard.Daly at realism.com> 
Cc: "Joe D Williams" <joedwil at earthlink.net>; "X3D Public" <x3d-public at web3d.org> 
Sent: Thursday, October 20, 2016 10:34 PM 
Subject: Re: [x3d-public] Purpose of X3Dng -- Animation 



2016-10-21 6:23 GMT+02:00 Leonard Daly <Leonard.Daly at realism.com>: 

In all your writings you appear to be making the assumption that joint-based 
animation with deformable skin is H-Anim. That is not true. 

Hi, 

>From my point of view, I see H-Anim as "the way to do animation using 
skeletons, bones and (optional) skins in X3D". I can easily do 
skeletal animation of anything (humans, pipes, animals) with H-Anim. I 
actually implemented it in view3dscene, and really there's nothing 
limiting this system to "humanoids". You just transform the bones, and 
optionally deform a mesh following the per-vertex weights. 

Maybe we could solve the issues raised here by simply changing the 
wording (and some node names), to de-emphasize the "humanoid" part in 
the H-Anim specifications. (The X3D component 
http://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/hanim.html 
and the H-Anim spec on 
http://h-anim.org/Specifications/H-Anim200x/ISO_IEC_FCD_19774/ ). 

Such change would more accurately reflect H-Anim's capabilities (in my view). 

How about we would simply rename H-Anim component in X3D to "Skeletal 
Animation"? Some additional renames would be nice, like removing the 
"HAnim*" prefix from nodes, and the main "HAnimHumanoid" node could be 
something simpler like just a "Skeleton" (with the primary field being 
"skeleton"). 

The fact that the H-Anim standard defines also a standard "Structure 
of a humanoid" is just "an extra" for me. I mean, it is valuable!, but 
it can also be simply ignored if you don't model a humanoid (or don't 
care about standardizing your names, to transfer the animations 
between other humanoids). 

Also, adding such "Skeletal Animation" component to the "Immersive" 
(or even earlier) profile would be a nice touch. It is a major 
animation method. Putting it inside a component other than "Full" is a 
way of encouraging implementations of it. Especially since it seems we 
do have a lot of implementations of it. 

It would be fantastic if e.g. Blender armature animation was exported 
to X3D. It is already possible, as H-Anim supports the necessary 
features --- what is miss is the actual code on the side of Blender 
(Python) exporter to X3D. 

I hope that this opinion helps:) 

Best regards, 
Michalis 

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all the best, Don 
 
 
-- 
Leonard Daly
3D Systems & Cloud Consultant
LA ACM SIGGRAPH Chair
President, Daly Realism - Creating the Future 
 


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-- 
Leonard Daly
3D Systems & Cloud Consultant
LA ACM SIGGRAPH Chair
President, Daly Realism - Creating the Future 
 



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