[x3d-public] X3D minutes 4 September 2020: Web3D 2020 submission dates, X3D4 PBR spec review

[Don Brutzman]

Attendees: Anita Havele, Vince Marchetti, Nicholas Polys, Dick Puk, Don Brutzman

Prior minutes

[0] [x3d-public] X3D working group meeting, 28 AUG 2020: SIGGRAPH 2020, X3D Tooltips, X3D Validator, Blender 2.90, work planning
     https://www.web3d.org/mailman/private/x3d-public_web3d.org/2020-August/013494.html

Confirmed that no member-only information is included in these minutes.

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1. Events

a. Web3D 2020 deadlines

[5.0] Web3D 2020, Important Dates
        https://2020.web3dconference.org/important-dates

7 SEP, Paper/poster acceptance

12 SEP 2020, Tutorial and workshop submission

19 SEP 2020, Industrial use cases submission

19 SEP 2020, Standards session submission

21 SEP 2020, Camera-ready paper/poster

26 SEP 2020, Demonstration submission

12 OCT 2020, Tutorial/workshop/demonstration/industrial use cases acceptance

12 OCT 2020, HAnim competition submission

We are on schedule.  We will be archiving every presentation and video and model, including both images and 3D models on the published pages.

For everyone's sake:  WRITE YOUR ABSTRACT PLEASE !!

X_ITE update linked, revving X3D Examples

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b. Software release.  Blender review - who is testing the new 2.90?  Any progress or problems?

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c. Parallel activities: Audio and Sound, Web3DUX.  See minutes posted to x3d-public list.
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d. C/C++/C# SAI progress review was very useful - separate minutes posted to x3d-public list.

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2. XML encoding of SF/MFString: pushed to next week.

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3. X3D4 PBR specification review

a. Gamma dialog in progress... email thread follows.

[3.0] [x3d-public] X3DOM Documentation: Gamma Correction (thread)
       https://www.web3d.org/mailman/private/x3d-public_web3d.org/2020-September/013504.html

[3.1] Gamma Correction in Future X3D
       https://github.com/michaliskambi/x3d-tests/wiki/Gamma-Correction-in-Future-X3D

Am hopeful that this is converging on a specification improvement.  We discussed how an SAI service is sufficient to handle this, while acknowledging that an Environment node might be helpful (in Environmental Effects component perhaps). Besides saying "do the right thing" an author might expect, at a minimum, to be able to turn gamma correction on or off.

I recommend we get gamma properly defined first, and only consider whether a node is appropriate when we have a proposal to that effect.  We should also be careful about any scene-presentation properties that might overlap with AR/MAR/XR composition.

Of interest:

[3.2] X3DOM Gamma Correction
       https://doc.x3dom.org/tutorials/lighting/gamma

[3.3] X3DOM documentation, Node: Environment
       https://doc.x3dom.org/author/EnvironmentalEffects/Environment.html

[3.4] X3DOM Screen Space Ambient Occlusion
       https://www.x3dom.org/examples/simple-screen-space-ambient-occlusion

Gamma is typically a "global" property since it relates to display.  It is important to have gamma correction regardless of color model.  Nevertheless it is possible to apply it selectively to shapes/images... whether it makes sense to offer that, or if selective gamma is simply a specialized rendering modification, needs to be considered.

Hoping we can reach consensus regarding gamma correction on mailing list and then update Mantis and X3D Specification accordingly.

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b. Color models. We need to review what specification needs to say about SRGB color model, this likely needs to be updated from RGB/RGBA support to include SRGB match other specs (like glTF) satisfactorily.  Other color models CMYK or CIE might be appropriate but they are used for printing.  Not a factor in 3D printing currently (a wild wild West of color).  Might be a factor in HTML space, plan to look at W3C Web Publishing working group and see if they mention it.

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[3.5] sRGB (standard Red Green Blue)
       https://en.wikipedia.org/wiki/SRGB

     1 The sRGB gamut
     2 The sRGB transfer function ("gamma")
         2.1 Ambiguity in the definition of the term "gamma"
     3 Specification of the transformation
         3.1 The forward transformation (CIE XYZ to sRGB)
         3.2 The reverse transformation
     4 Theory of the transformation
     5 Viewing environment
     6 Usage
     7 See also
     8 References
         8.1 Standards
     9 External links
========================================

[3.6] Wikipedia: Color model
       https://en.wikipedia.org/wiki/Color_model

"A color model is an abstract mathematical model describing the way colors can be represented as tuples of numbers, typically as three or four values or color components. When this model is associated with a precise description of how the components are to be interpreted (viewing conditions, etc.), the resulting set of colors is called "color space." This section describes ways in which human color vision can be modeled."

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c. Point and line rendering.

Michalis has written up the results of last week's work on regularizing the handling of normals and lighting for PointSet, LineSet and IndexedLightSet.  This is getting put in Rendering component under Common geometry fields.  This is also summarized at:

[3.6] Points and lines rendering
       https://github.com/michaliskambi/x3d-tests/wiki/Points-and-lines-rendering

We performed an excellent amount of specification prose review today.

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d. 12.2.3 Two-sided materials

... mentions "fields xxxTexture and xxxTextureMapping" which should be addressed individually, listing each field individually.  We will do that in a future editing session.

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e. Michalis Dick and Don will meet Monday to work further on X3DUrlObject glTF support.

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4. Coming up

TODO update X3D Examples Archive to latest version of X_ITE

TODO check support, encourage implementation: Projective Texture Mapping (PTM)

TODO Need to highlight collection of X3D4 examples...

*WRITE WRITE WRITE* those Web3D 2020 tutorial and workshop submissions!

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Have fun with X3D4 - or else!  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