How can i get this reflectivity?

[Jpjapers]

I have this floor tile material thats made of rubber and it is quite hard to replicate in corona. if i make it too matte the overhead ligting washes out all the colour but too gloss and its far far too shiny. i tried playing with falloff but i cant seem to get it right. Its pretty basic but im still getting used to making decent materials.

Here is a picture of the flooring in question
https://forbo.blob.core.windows.net/forboimages/3226/1480500704776-B.jpg

[Njen]

According to PBR energy conservation rules and assuming your specular colour is white, and that your IOR is correct (most dielectric materials have an IOR between 1.3 and 1.7, with 1.52 being the safest number), it all comes down to a fine balance between glossiness and bump. I'm not sure why you are using falloffs, but you don't need them.

[Juraj]

I think he meant fallof in glosiness to boost the glossiness towards grazing angle. GGX does this by default, but not to an extent lot of materials, particularly rough exhibit.

[pokoy]

I guess besides the roughness falloff anonther key factor will be the floor's structure. All shading models assume a certain surface and model light distribution according to that. There are surfaces that will deviate from this norm. In my former office we had an industrial tile floor that would be really impossible to do in cg, totally rough but still high intensity reflection would somehow 'break through' and tint white reflections in a soft orange tone. I never understood why it looked like that because looking from a cg perspective it would be impossible without tricks, coating etc.
One of the older architects from the office downstairs told me this was a typical 60s industrial artificial floor produced from stone powder, soaked in a glue of some sort and coated with tar (a real killer for your lungs but these were the 60s). So the structure was quite porous - you could wash off the tar with a wet tissue - but the tar added a soft reflective coating.
I suppose your example might be doable with a little help from tiny noise as bump to roughen the reflection, but not sure how that adds up in final sampling.

[Juraj]

Yeah micro-bump is really problematic in how it breaks down in different angle and resolution in sampling. One of those things rendering engines could improve in next, similar to that Siggraph paper on micro-scratches. Could simulate this kind of roughness better than glossiness effect (and also makes amazing natural anisotrophy).

For now, I would do glosiness fallof (use the fresnel mode inside it) and some coating.

[maru]

Another thing is the brightness of the "enviro" (by that I mean the ambient light in the scene, and the dimmer light sources) and the main light sources. If the enviro lighting is dark, and the main light source very bright, this will cause a lot of contrast in the reflection. Recreating the material based on the reference photo would probably require matching the enviro lighting and the main lights to that photo as closely as possible.

[Jpjapers]

Ok thanks guys ill keep at it.