Iridescence test model?

[bhouston]

I notice that the current iridescence feature is implemented inconsistently in a lot of renderers. Basically the colors differ in each renderer. I wonder if that is in part because we do not have clear test files for iridescence.

Basically a test that isolates iridescence and looks at it across its parameter space so that people can easily validate their implementations.

It may be nice to have a test file for iridescence that has different thickness (min, max) in a row each on say a block with a varying thickness texture. Then people can compare the behavior under different conditions to ensure proper behavior.

cc: @echadwick-artist

[bhouston]

We noticed this as we are adding Blender Cycles and Chaos V-Ray to @elalish's Model Viewer fidelity test suite:

• https://github.com/google/model-viewer/issues/4482
• https://github.com/google/model-viewer/issues/4483

[echadwick-artist]

We have some test models in the new glTF Sample Assets repo, which is meant to replace glTF Sample Models (once we get the kinks worked out).

• IridescenceMetallicSpheres has a 3d grid of spheres representing the combinations of three settings: iridescenceThickness, baseColorFactor, and iridescenceIor.
• IridescenceSuzanne has an iridescenceThicknessTexture, but it's not representing specific values.

I guess we could add a unit test example that uses a texture to represent specific iridescence thicknesses.

[bhouston]

Amazing as usual @echadwick-artist ! Duplicate repos are confusing. :)

[DRx3D]

@bhouston : Is this issue complete with these models in the repo?

• Anisotropy: https://github.com/KhronosGroup/glTF-Sample-Assets/blob/main/Models/AnisotropyBarnLamp/README.md
• Iridescence: https://github.com/KhronosGroup/glTF-Sample-Assets/blob/main/Models/IridescenceAbalone/README.md

There are others too.

[DRx3D]

If there are no responses to this comment by 27 Nov, it will be closed.

[DRx3D]

No responses by cutoff date - closing.