[x3d-public] Physically Based Materials (PBR) in X3D

[Don Brutzman]

Yes Michalis your thoughtful insights are much appreciated.

The essential approach and X3D extensions proposed in the Fraunhofer paper will need to get checked with respect to glTF 2 (and its likely evolution) of course.  Further considerations for X3D Programmable Shaders Component might also emerge.

In the paper, "Figure 2: Pre-calculated environment map, with varying roughness levels stored in different mipmap levels" is pretty interesting.

We may also see some interesting work published at Web3D 2018 Conference in Poznan Poland this summer (June 20-22) also.  Since this topic is so fundamentally important, we should probably plan on organizing a rendering BOF there.

	http://web3d2018.web3d.org

Regarding forward compatibility.  If these changes to the X3D Rendering Component and Lighting component are proposed as an experimental Physically Based Rendering Component in version 4.0, that encourage support for broader experimentation and experience.  Further am thinking we may get further insight regarding video/overlay rendering considerations when we had VR/AR/MAR support in X3D v4.1, so deferring final formalization until then may help avoid unexpected future mismatches when integrating WebVR, background video, 360 video, chroma-key composition, and related capabilities.

Regarding backwards compatibility.  It would be interesting to consider whether, instead of adding new nodes, we might go ahead and completely extend existing Material node and other lighting-related capabilities.  This has potential benefit of keeping the X3D v4 scene graph more closely consistent for X3D v3 and VRML97 content, allowing superior rendering of all content as the default rendering mode in X3D v4.  A backwards-compatibility rendering mode also might be possible for when authors explicitly want it...  But there might be real merit into establishing a higher baseline level of visual quality in X3D v4 that encompasses all Inline content.  Shape information in those scene models all describe geometry and appearance that still remains functionally equivalent if rendered in a superior fashion.

Hope you can continue to expose and distill both insights and alternatives in your page.  Thanks for your many efforts.

On 3/15/2018 4:03 PM, Michalis Kamburelis wrote:
> Hi everyone,
> 
> (And "Hi" to Don especially -- this mail was inspired by our talk
> today, in which we ended talking about PBR. Thank you again!)
> 
> I wrote a little summary of my knowledge and thoughts about
> physical-based rendering (PBR) in X3D on
> 
>      https://github.com/michaliskambi/x3d-tests/wiki/Include-PhysicalMaterial-and-PhysicalEnvironmentLight-in-the-official-X3D-specification
> 
> This is mostly a summary of what I learned in recent months about PBR.
> I do not really propose anything that wasn't already proposed before,
> but I try to summarize my knowledge and provide useful links. Maybe it
> will be helpful for others too :) Many thanks go to everyone on this
> list, esp. Leonard Daly and Andreas Plesch, for all the informative
> mails about glTF and PBR!
> 
> Best regards,
> Michalis
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