[RESOLVED] Fabric - fIOR

[cjwidd]

Are there any hard and fast rules about fabric fIOR values? For example, in general <1.52 fIOR? Are there any general tips for gloss falloff curves?

[cjwidd]

Just examined all the 'carpets' materials in the Corona material library and they all use 1.52

[James Vella]

You wont notice much difference with the IOR, the difference mainly comes from the gloss/rough map. Also with fabrics a falloff diffuse goes a long way.

This is why PBR standard is 1.5 for dialectric and basically off for metal materials.

You can see some tests ive done here regarding varying fresnel results if you are interested.



Ive linked you this before, most of the info is not relevant for this but this particular point is included in the research.
https://www.jamesvella.net/blog/2019/9/2/substance-designer-to-vraycorona

Also they go into this in more detail in the Substance PBR guide.
https://academy.substance3d.com/courses/the-pbr-guide-part-1

[cjwidd]

Right, after studying the materials more, it's really the falloff curve and SSS that is driving the fabric appearance, IMO