glass block refraction problem

[pailhead]

I have some refraction problems with the glass block that i have modeled.





The inner surface is not refracted at all through the outer surface.

Here is the max file, sorry for using rapidshare but thats my only option at this moment.

http://rapidshare.com/files/31210133/staklo.max.html

[DaForce]

If you use the same material on both inner and outter surfaces it appears to work correctly.
It seems its unable to work out the proper refraction if you use different materials.

[pailhead]

Is that... normal?

[DaForce]

Ahh... hard to say, I would think not.

I would have thought as well that no matter what material was on both surfaces it should be able to work out the proper IOR. But then again ... maybe not.
Since its meant to be a glass brick it would be all of one material in real life. So maybe vray works in the same way, it has to be all one material and you would just need to map the bump to the inside faces only. That should work.

Dunno, might need Vlado to chim in on this one.

[pailhead]

But let's say that you want to have the inner side painted with a thick semi transparent paint. Or that you want to have the whole block filled with water or some goo... You would have to have different materials with different properties in this case.


It seems like a bug, i would love Vlado to take a look.

[DaForce]

Yeah I agree it certainly does sound bug like.

[pailhead]

Vlado?

[vlado]

It's not a bug and it needs to be one material. V-Ray actually assigns a volume shader to each material and uses this to figure out the correct IOR at each surface. If you assign a different material to a back surface, V-Ray will assume that the volume of the original front surface is still continuing - which you will be able to see if you make the fog color something other than white.

Instead of using a different material on the back surface, you can use textures to modify the properties of the same material.

Best regards,
Vlado