[x3d-public] Discussion from the X3D WG Meeting Nov 30 2018

vmarchetti at kshell.com vmarchetti at kshell.com
Fri Dec 7 09:33:39 PST 2018

Discussion on X3D WG Meeting on glTF and X3D Specification

Attending Michalis Kamburelis. Dick Puk, Vince Marchetti, Nicholas Polys

Supporting Material:
X3d-public mailing list 

	• Plesch Nov 20: 
But the fact of the matter is that it is used increasingly as an exchange and
asset format (there are many exporters and importers). It is also the
case that many/most importers translate glTF into their native data
structures first, due to convenience (three.js does that, for example)
before uploading to the GPU

X3D needs PBR
PBR is the only coloring mechanism in core glTF2
Others available only as extensions.

X3D should have a mesh-efficient node [ compatible with glTD ]

Can have one one mesh with Phong shading, one with PBR: This is possible with shaders. Graphic artists will say this is incorrect.

Proposal: Implement a “PhysicalMaterial” node which will substitute for  the Material node as a field of the Appearance node

Approach: Implemented as a code extension to open source browswe (X3DOM, X_ITE, Xj3D)

Proposal: Implement a “gltFMesh” node which acts as a Geometry node similar to TriangleSet, but as URL field to retrieve glTF or glb  content. 

Approach : Direct implementation in as an open source extension fo x3dom code, potentially to be added to X3DOM master code

Benefits: Faster, smaller downloads, transmission of mesh-like geometry.

Proposal: Implement “Image Based Lighting” node, “Physical Light Source”, related to the cube map.

Indeed. If we have

- BufferGeometry (node that can be placed in "Shape.geometry",
compatible with glTF mesh)
- PhysicalMaterial (node that can be placed in "Appearance.material",
compatible with glTF material using PBR)
- EnvironmentLight (to cast light as a cubemap, hopefully useful with
both PBR PhysicalMaterial and Phong Material)

... then we're ready to easily import at least static glTF models in X3D.

See also various notes from my [wiki]

Submitted Dec 7 2018

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