[x3d-public] 3D Working Group agenda 23 FEB 2023: progress reports, proposed Metaverse group, glTF extensions, X3D 4.1 feature discussion

[Andreas Plesch]

Hi Holger, Michalis,

The glTF lights map pretty well to the X3D lights. But there are some
differences in terms of attenuation and umbra and perhaps other
details, I believe. Could you point me to how you deal with these
minor differences before I start to perhaps implement ?

Thanks, Andreas

On Fri, Feb 24, 2023 at 1:32 PM Holger Seelig <holger.seelig at yahoo.de> wrote:
>
> X_ITE supports the following extensions:
>
> - KHR_materials_unlit implemented with PhysicalMaterial because of gamma correction.
>
> - KHR_materials_emissive_strength - implemented by adding emissiveStrength field to X3DOneSidedMaterialNode.
>
> - KHR_lights_punctual - mapped to Point/Spot/DirectonalLight
>
> - KHR_texture_transform - mapped to X3D TextureTransform
>
> - KHR_materials_pbrSpecularGlossiness - not really supported, without a SpecularGlossinessMaterial node there will be no real support, but PhysicalMaterial is more straightforward.
>
> Best regards,
> Holger
>
>
>
> Am 24.02.2023 um 19:15 schrieb Michalis Kamburelis <michalis.kambi at gmail.com>:
>
> From others:
>
> 1. Blender: they support a number of extensions at import and export:
> https://docs.blender.org/manual/en/dev/addons/import_export/scene_gltf2.html#extensions
>
> 2. CGE supports ( https://castle-engine.io/gltf ):
>
> - KHR_materials_unlit - unlit materials. This translates nicely to
> X3D4 UnlitMaterial.
>
> - KHR_lights_punctual - define lights (point, spot, directional)
> within glTF file. These translate nicely to X3D lights (with unbounded
> intensity in X3D4).
>
> - KHR_texture_transform - transform (scale, offset, rotate) texture
> coordinates. These translate to X3D texture coordinate transformation
> nodes.
>
> - KHR_materials_pbrSpecularGlossiness - support for alternative
> specification of material parameters using specular-glossiness. Only
> partial support — without textures. Extension considered deprecated by
> Khronos in favor of KHR_materials_specular.
>
> My most important plans:
>
> - X3D nodes for binary meshes (I know X3DOM has this already) and then
> KHR_draco_mesh_compression
>
> - EnvironmentLight in X3D4, consistent with EXT_lights_image_based ,
> KHR_lights_environment .
>
> 3. Everyone: As you see, there is a big overlap between all these
> extension lists (X3DOM, Blender, CGE) and that's good :)
>
> Some glTF extensions are quite popular and in practice supported by
> all/most glTF viewers.
>
> Regards,
> Michalis
>
> pt., 24 lut 2023 o 17:56 Andreas Plesch <andreasplesch at gmail.com> napisał(a):
>
>
> On glTF extension below:
>
>
> ...
> 4.      glTF Extensions.
>
> Recent email threads have pointed out that X3D 4.0 normatively references
> glTF 2.0.  Meanwhile numerous glTF extensions are available.  Nothing
> prohibits X3D browsers/players/tools from going beyond baseline glTF 2.0 -
> the "X" in X3D is Extensible.  8)
>
> There is benefit to software developers, content authors and end users to
> having a shared strategy on what new features to support.  Considering and
> supporting such a list is further suitable as a Web3D Recommendation as a
> stepping stone towards future pursuit of X3D 4.1 with International
> Standards Organization (ISO).
>
>
>
>
> Here are a few glTF extensions that have been proposed.  Let's discuss which
> have high value and deserve consideration as part of a shared strategy.
>
>
>
> *       EnvironmentLight
> *       emissiveColor bloom
> *       Draco geometry compression
> *       Human animation
> *       Others?
>
>
> x3dom supports a few extensions:
>
> "KHR_materials_pbrSpecularGlossiness", (now deprecated and replaced by
> KHR_materials_specular)
> "KHR_materials_unlit",
> "KHR_texture_transform"
>
> Soon it will also support Draco decompression.
>
> KHR prefixed extensions are sanctioned by Khronos.
>
> Here is a complete list:
>
> KHR_draco_mesh_compression
> KHR_lights_punctual
> KHR_materials_clearcoat
> KHR_materials_emissive_strength
> KHR_materials_ior
> KHR_materials_iridescence
> KHR_materials_sheen
> KHR_materials_specular
> KHR_materials_transmission
> KHR_materials_unlit
> KHR_materials_variants
> KHR_materials_volume
> KHR_mesh_quantization
> KHR_texture_basisu
> KHR_texture_transform
> KHR_xmp_json_ld
>
> KHR_lights_punctual may be feasible to support, and KHR_xmp_json_ld is
> about metadata and also should be possible to translate to Metadata
> nodes.
>
> EXT_lights_image_based is a multi-vendor extension related to EnvironmentLight
>
> -Andreas
>
>
>
>
>
>
> 5.      X3D 4.1 feature discussion. (carried over from last week)
>
>
>
> Many possibilities!  The "X" in X3D is Extensible, so pursuit of further
> evolution is an essential part of our design.  We benefit from (but are not
> limited by) ISO stability, since implementers can experiment with innovative
> practices and also match Web3D Consortium recommended practices.
>
>
>
> a.      Near term: resolving Sound component differences with Web Audio API.
> Some noted issues will likely get deferred as X3D 4.1 issues.
> b.      In progress: HAnim2/X3D4 additions for site names, poses, and
> clothing to provide support for apparel.
> c.      What else? What's next?
>
>
>
> Wishing best progress.  Have fun with X3D!  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 https://
> faculty.nps.edu/brutzman
>
>
>
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> --
> Andreas Plesch
> Waltham, MA 02453
>
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-- 
Andreas Plesch
Waltham, MA 02453