PBR Textures

[jon_leeke]

Hello, I was wondering if someone was able to clear up a question when using PBR textures. I have dropped the roughness texture in the glossiness channel and checked use as roughness but what do we set the Reflection Channel too? Obviously with a set of PBR textures there is no image to add and guessing a colour seems a bit random given the nature of PBR. Is there a default for this channel?

Thank you

[sirio76]

In general you can set the reflection color to white, if needed tune the metalness value (1 for metal 0 for smithing else).

[jon_leeke]

Thank you. I'm creating an asphalt, when I set the reflection to white the material look a little un-natural with too much reflection. Of course I can lower the value but with a range of 0 - 100 it seems a bit of guess work to know what is correct for something that is supposedly 'physically based'. Is their a way to calculate what this value should be on a specific material?

[stefan_laub1]

according to the some "latest" physical based material systems, (as chaos made in in corona render p.e) they reflection is indeed white, but the ior value isnt a fix value like 1.6 but for most materials quite lower. a lower ior results in a lower reflection value/curve.

the more classic way would be to reduce the reflection color, or even use a copy of the diffuse texture there, with a mix value(like 50% or less)

as there are no measured values for most real world materials, the value is defined by your needs and your eye. so manually set by ior value or refl color slot intensity.


p.s.: to get a feeling this site has several measures data and reflection intensity curves that might help too understand the reflection curve from different material types: https://refractiveindex.info/?shelf=...C&page=Singh-o

[boyan]

Hello, Jon!


Thank you for your inquiry. I implement a pretty basic setup with texture maps exported from SP within the V-Ray shader.


Cheers,

[jon_leeke]

That's great, thank you this now makes sense