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<p>I just wrote a post about using X3D as a Standardized Model
Archive format. The article is at
<a class="moz-txt-link-freetext" href="http://realism.com/blog/model-archive-format-x3d">http://realism.com/blog/model-archive-format-x3d</a>. This message
summarizes and quotes portions of it for discussion.<br>
</p>
<p>I mentioned a number of formats include FBX, OBJ, glTF, and X3D
as possible candidates for an archive format. X3D is the only one
that is ISO standardized. Vince has pointed out that glTF is not
an archive format in that the file contains data in a format that
allows it to get into the GPU with minimal processing".<br>
</p>
"It is important that models exist to be imported into a scene (or
sub-scene). The models may contain animation, but this key-frame
animation that indicates what part of the model needs to be where at
various relative time values. Models do not contain a run-time or
interactive component. Neither do they contain lighting or
environmental effects (backgrounds, fog, etc.). These features are
added in the scene rather than to the model."<br>
<p><b>Current </b><b><b>Industry </b>Work Flow</b><br>
</p>
<p>"The current state of modeling creates a quad-mesh as the surface
geometry of the object. The model is animated either as multiple
meshes (rigid body animation) or (much more frequently) as skin
deformations due to joint movement. Faces or other highly
deformable surface with a fixed underlying structure are animated
as morphs using morph targets. [The target is a linear combination
of a basis set and the animation is the path to get from existing
to target.] Textures are created and applied to the model. "<br>
</p>
A note on animation: FBX has established the standard (by use) of a
single master timeline for all animations. Individual animations may
occupy just a portion of that timeline.
<p><b>Model Profile Requirements</b><br>
</p>
<p>A Model Profile needs to provide archive support for all of the
ways people model, texture and other appearance, and animate. <br>
</p>
<p> * 3D geometry capabilities<br>
- Triangles<br>
- Quads<br>
- CAD (NURBS, CAD structures)</p>
<p> * Appearance capabilities<br>
- Image texture<br>
- Advanced texturing (bump, emmisive, occlusion, etc.)</p>
<p> * Animation capabilities<br>
- Single timeline<br>
- Skin/joint motion<br>
- Morphing & Morph targets<br>
</p>
<p>I believe that most of this is easy to accomplish with material
in V3.3. The new/revised capabilities could be added for V4.0. In
conjunction with the definition, a 2-way conversion library should
be provided. Inbound would be calls to create the appropriate X3D
data structure. Outbound would handle things like triangulation.
It might also be good to have a single file format where the X3D
and external media files are zipped/merged together.<br>
</p>
<div class="moz-signature">-- <br>
<font class="tahoma,arial,helvetica san serif" color="#333366">
<font size="+1"><b>Leonard Daly</b></font><br>
3D Systems & Cloud Consultant<br>
LA ACM SIGGRAPH Chair<br>
President, Daly Realism - <i>Creating the Future</i>
</font></div>
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