[x3d-public] 3D Working Group agenda 23 FEB 2023: progress reports, proposed Metaverse group, glTF extensions, X3D 4.1 feature discussion
Holger Seelig
holger.seelig at yahoo.de
Fri Feb 24 11:05:56 PST 2023
I have done this, as shown below, not handling umbra and attenuation leads to (0, 0, 1):
All:
light === gltf .light
lightNode .color = light .color
lightNode .intensity = light .intensity
Spot:
lightNode .radius = light .range
lightNode .cutOffAngle = light .outerConeAngle
lightNode .beamWidth = light .innerConeAngle
lightNode .attenuation = (0, 0, 1)
Point:
lightNode ._radius = light .range
lightNode ._attenuation = (0, 0, 1);
Note that radius 0 means infinity.
Best regards,
Holger
> Am 24.02.2023 um 19:43 schrieb Andreas Plesch <andreasplesch at gmail.com>:
>
> 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
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