Docs: Improve MeshPhysicalMaterial page.

[Mugen87]

Fixed #23509.

Description

Added some missing properties of MeshPhysicalMaterial. Adapted the descriptions of the KHR_materials_volume spec.

The thickness description is preliminary and has to be enhanced when #23448 is implemented.

[WestLangley]

I'd suggest using the complete definitions in https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_materials_volume.

(Except the double-sided comment for now.)

[WestLangley]

The three.js docs specify default values, but fail to specify ranges. This should be fixed throughout the docs.

[Mugen87]

I'd suggest using the complete definitions in https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_materials_volume. (Except the double-sided comment for now.)

Done!

The three.js docs specify default values, but fail to specify ranges. This should be fixed throughout the docs.

Agreed. But I'd like to suggest to make this clean up in a different PR and keep the current policy for this one.

[WestLangley]

I'd like to suggest to make this clean up in a different PR

Oh yes, that is what I assumed. :-)

[mrdoob]

Thanks!