[x3d-public] Purpose of X3D

[Joe D Williams]

< > X3D has not kept up with current practices in modeling, animation, 
rendering, or interaction.

So, finally an opportunity to actually make a list of features and 
benifits missing from X3D.

Modeling

X3D is missing an automated method for defining deformable skin 
animation bindings between skeleton and skin.
Most character model authoring systems will produce a fairly good set 
of data using some author interaction and basic algorithms to 
determine skin vertex assignments and weight for each HAnim Joint. X3D 
can directly use binding data if exported from most any tool, but 
otherwise the X3D author has to figure out these monumental details 
using just the keyboard and an intense familitity with the skin mesh 
vertex order of appearance in the user code, and each joint of the 
skeleton.

This automation might be compared with the automatic texture 
coordinates generated for the IFS, except much more complicated. But 
if there was simple way to define basic bindings then the X3D author 
could have a starting point for refinements.

Finally, we need some basic rules and recommendations for converting a 
typical skeleton or skelton-skin rig from a typical design tool vendor 
to our dearly beloved 'standard' X3D HAnim character. This is 
necessary in order to reliably import animations developed in a 
typical mocap setup into X3D HAnim.

Thinking of mocap, usually the skeleton may have a different number of 
Joints than HAnim, and the names are different. Usually this is OK 
because the HAnim playback skeleton will have a higher level of 
articulation than the capture skeleton. It is usually fairly easy to 
determine coorespondence between the capture and playback skeletons 
and thus transport the animations, but we need some documentation and 
examples showing a process

Animation

I have confidence that we have most all features needed for basic 
realtime animations: timers, interpolators, easein-easout, and routes.
DIfferent methods of interpolation?
DIfferent models for producing motion?
 rigid body physics for HAnim
Different variable types for animation data?
 That is it - a big hole: X3D doesn't do quats in the user code.

Rendering

Significant interest in rendering at fixed frame intervals to video or 
film (not realtime).
X3D does this fine and it is easy if you know a couple of details 
about X3D, but there are no visible application handles for defining 
how to make a fixed frame per second video or film from realtime 
animations.

First there may be a need to import mocap-style fixed interval 
keyframe data of several forms (euler, axis-angle, quaternions), 
convert the data to X3D axis-angle interpolators and playback in real 
time with interpolation. This is good because with tuning these 
animations can be used with any 'standard' HAnim character.

Next there may be a need to import mocap-style fixed interval keyframe 
data of several forms and playback using the exact same key times as 
data was acquired, thus using only the actual keyvalue data with no 
interpolation. This would be ok for a basic X3D video maker

Interaction

OK, what forms of interaction? We have basic pointer sensing and 
interactions OK,.
Are there clues in MARS and related VR? Have a look at some of the 
presentations from last SC24 that Myeong put up at googledocs.

Thanks Again Leonard for thinking about this stuff and Best Regards,
Joe




.
----- Original Message ----- 
From: "Leonard Daly" <Leonard.Daly at realism.com>
To: <x3d-public at web3d.org>
Sent: Wednesday, October 12, 2016 9:20 AM
Subject: Re: [x3d-public] Purpose of X3D


> There were far more responses to this message than I thought would
> happen. It has taken me a while to even make a first-pass read 
> through.
> I want to thank people for being interested. I have started to work 
> on
> much more detailed description of where I think X3D should go (or at
> least consider). I will be posting those over the next month.
>
> Generally, I see a strong interest in declarative 3D with a 
> programmatic
> API. All regular, normal things should be able to be done 
> declaratively,
> with programmatic means restricted to special cases.
>
> Leonard Daly
>
>
>
>
>> I have been struggling with this topic for several months -- what 
>> is
>> the purpose of X3D in the electronic ecosystem of the 21st century.
>> The Consortium says that "X3D is a royalty-free open standards file
>> format and run-time architecture to represent and communicate 3D
>> scenes and objects using XML" [http://www.web3d.org/x3d/what-x3d]. 
>> As
>> an ISO standard, X3D needs to have a long shelf-life, contain 3D
>> models, animation, and interactivity; and communicate this within 
>> and
>> between systems using XML. To do this effectively, it needs to stay
>> current with industry practices while maintaining an ability to
>> communicate information from the past.
>>
>> There is no question about X3D's handling of old data. To my 
>> knowledge
>> there is no other 3D system that can display models, animation, and
>> interaction from 15+ years ago. In the Internet age where half-life
>> appears to be around 18 months, that is a remarkable achievement.
>>
>> X3D has not kept up with current practices in modeling, animation,
>> rendering, or interaction. Work on the most recent update to X3D 
>> (V3.3
>> - 2013) started back in 2009 and the document was mostly completed 
>> in
>> 2010. The most advanced feature is 3D volume rendering. Work on
>> particle systems and physics is several years before that. The
>> standard for animation of any model is with bones and rigs - 
>> whether
>> that model is a character, a tree, or a machine. All current 
>> renders
>> use shaders (code that runs on a graphics card) to create highly
>> realistic (or fantastic) surface appearance. Work on upgrading
>> interaction to support mobile devices (including multi-touch),
>> head-mounted-displays including game controllers, paddles, LEAP
>> interfaces, and other specialized devices is just beginning.
>>
>> So back to my question -- what is X3D for? In 20 years time will 
>> the
>> only content for X3D be 35 years old? Current content not created
>> explicitly for X3D won't work because X3D does not support much 
>> more
>> than static modeling.
>>
>> I have collected several choices. These are described below in more 
>> or
>> less least to most complex (aka work). There are a lot of other
>> options, more towards bottom of the list. If you have other
>> contributions, please feel free to state so along with what you 
>> think
>> it would take to get there from X3D V3.3.
>>
>>  1) X3D is for static models only (no texture). This is a very good
>> match. There are just a few things that X3D doesn't handle and most 
>> of
>> those are having to deal with interchange with other formats.
>>  2) X3D is for static models + appearance. X3D needs to expand to 
>> make
>> full use of appearance shaders of all sorts.
>>  3) X3D is for models including animation. X3D needs to expand to
>> include at least the current practice of skeletal structure plus
>> rigging (attaching surface weights to various joints). This is not
>> H-Anim, but broader as it includes models that are not even at all
>> human, human-like, animals, or even "living".
>>  4) X3D is for runtime display. X3D needs to include all major 3D
>> formats. It needs to run AND use interface mechanisms of all major
>> platform types, including phones/tablets, HMDs, desktops, etc. It
>> needs to run in a browser: it needs to run as an app.
>>  5) X3D is everything. Well, think about that for a moment. That 
>> means
>> all of the above need to be done. It also needs to be widely 
>> adopted,
>> and this needs to be completed in the next 12-18 months. It would
>> probably take a team of 20-50 people working on a specification,
>> implementations, conversion, integration applications, marketing, 
>> etc.
>> to accomplish this. Advocates for this choice need to have a 
>> reality
>> check.
>>
>> Given that we have maybe 7 part time people (right now) where does 
>> X3D go?
>>
>> -- 
>> *Leonard Daly*
>> 3D Systems & Cloud Consultant
>> LA ACM SIGGRAPH Chair
>> President, Daly Realism - /Creating the Future/
>>
>>
>> _______________________________________________
>> x3d-public mailing list
>> x3d-public at web3d.org
>> http://web3d.org/mailman/listinfo/x3d-public_web3d.org
>
>
> -- 
> *Leonard Daly*
> 3D Systems & Cloud Consultant
> LA ACM SIGGRAPH Chair
> President, Daly Realism - /Creating the Future/
>


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