[x3d-public] X3D and glTF Features Comparison

[Joseph D Williams]

So, doing some more looking, I find the morphing features need a native mesh, a set of values that define the fullymorphed absolute max displacement of each mesh point relative to the native mesh. Data requirements are the same as for X3D hanim displacer. Of course, as Leonard has mentioned, maybe somebody should bring the displacer out of dedicated hanim to be in some category of more automated coordinateinterpolators? 

Unfortunately, like doing real joint-driven deformable skin or a displacement-based morpher is a step above typical capabilities required for interactive realtime x3d browser – ya need full hanim component, for now.  For composition, the morpher-style animation may make it easy to substitute a set of only the start and end (0 to 1, maybe) mesh points then use interpolation to define the state of the morph, instead of defining several intermediate meshes. For simple stuff, big hint: if you can do it with a two sets of meshes in a coordinate interpolator, then a the morpher , or displacer is more simple to code – if your editor will give you relative position values between two meshes, then you got it. 

This data would be made live in a scene when, for example, the data is used to deform the mesh according to runtime providing some fraction or weight for the unmorph to fullmorph mesh state for that frame, and some interpolation. For real time this is harder to do so look at x3d hanim examples to see displacer in action. Thus, as basic x3d hanim structures can be easily represented in glTF, so can any sort of animations. Same number of points required, same spacetime required, only the field names and your names may be different depending upon the underlying animation structures of current realtime rendering robots. Like the rest, given the identicalityness of the data and data structures, the very general x3d hanim displacer and a typical two step morpher is just a style sheet away - either way you want to author it, store it, transport or transcode it, and finally, most importantly, run it anywhere using x3d for the www. 

Thanks and Best, 
Joe




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From: Joseph D Williams
Sent: Saturday, December 23, 2017 8:29 PM
To: Don Brutzman; X3D Graphics public mailing list
Subject: Re: [x3d-public] X3D and glTF Features Comparison

Morph targets No Yes

X3D does morph targets using HAnim Displacer (standard coordinateinterpolator operations do it too). As long as the number of points is the same from begin to end morph, then all is as expected. 
Joe

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From: Don Brutzman
Sent: Saturday, December 23, 2017 12:24 PM
To: X3D Graphics public mailing list
Subject: [x3d-public] X3D and glTF Features Comparison

The X3D Working Group is please to release an updated X3D and glTF Features Comparison.

Since we are considering how glTF might be included as loadable external geometry in X3D version 4, the comparison spreadsheet is attached at

           X3D Version 4 | Web3D Consortium
           http://www.web3d.org/x3d4

           glTF X3D Features Comparison (3 NOV 2017)
           http://www.web3d.org/sites/default/files/page/X3D%20Version%204/glTfX3dFeaturesComparison.pdf

Several months of dedicated review and consideration has produced this excellent document, building on important initial work by Leonard Daly.

Further review, comments and improvements are welcome.  Have fun with X3D and glTF!  8)

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


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