material bugs in build 3

[flipside]

Hi,

- refraction doesn't work at all, renders very very weird things, no matter what fog or refraction colors or multiplier I use.
- highlight glossiness doesn't work
- you can't set highlight glossy if reflection glossy is 1.0 (it resets to 1.0 all the time)

[joe_b]

material bugs in build 3

the glass material has been updated by Vlado for this build. It is supposed to act more like it does in max, but I suppose I have messed something up somewhere. I'll see what I can find.

About the hilight and reflection glossiness. Let me explain the current setup for how our materials work. Our custom material consists of multple BRDFs depending on your configuration. Diffuse, Mirror, Blinn, Phong, Glass respectively for the Diffuse, Mirror Reflection, Glossy Reflections, and glass is, of course, Refraction. Currently in our setup when the reflection glossiness is 1 that means you get a mirror only. So the hilight glossiness does nothing when reflection is 1.0. Not to say this will stay this way, but thats how it is right now. When you have a reflection less than 1.0 we then have a Mirror with a Blinn or a Phong (depending on what shader type you want for the glossy's) Now the glossies make use of the hilight glossiness value.

I'm sure you remember when the fresnel didn't work for the glossies at all, that was a similar problem, we had to modify some of the BRDFs to allow fresnel to work on them. So Corey and I still have to mess around with the material layout before everything should work together as they should. Vlado has been been of great help to us because he is helping us understand exactly how he does this in VRay for Max so we're definately making progress.

Wow, I didn't intend for this post to be this long I hope this can be helpful to everyone who is curious about how our materials work (don't work? )right now.

[flipside]

material bugs in build 3

Ok I get it now, it's logical that when there is no reflection, there is no highlight either.

But sometimes the user needs highlight glossy only (without the need for time consuming real glossies), so that would mean refl glossy=1.0 and highlight glossy < 1.0.

For cases like this, it would be nice if options get grayed out when they have no effect in a given configuration (gijs mentioned this already I think).

[vlado]

material bugs in build 3

Refraction looks wrong to me too... try to render a simple glass sphere on a plane and compare the result to the sample renderer in the V-Ray SDK, for example.

On another note, I'm not sure how the fog stuff is implemented (e.g. do you always create a fog volume shader?), but the volume has an IOR parameter too; if a volume is present, the Fresnel texture and the Glass BRDF will take the IOR from the volume, and not from their own settings. In the 3dsmax exporter script, for example, all three IORs are typically set to the same value.

Best regards,
Vlado

[joe_b]

material bugs in build 3

Refraction looks wrong to me too... try to render a simple glass sphere on a plane and compare the result to the sample renderer in the V-Ray SDK, for example.

yeah me and flipside figured out the problem. The fog color mult and ior values are swapped. So the box that says IOR controls the fog color mult, and the box that says Fog Color Mult is actually the IOR. Whups!

On another note, I'm not sure how the fog stuff is implemented (e.g. do you always create a fog volume shader?), but the volume has an IOR parameter too; if a volume is present, the Fresnel texture and the Glass BRDF will take the IOR from the volume, and not from their own settings. In the 3dsmax exporter script, for example, all three IORs are typically set to the same value.

Currently the custom material uses the volume shader whenever the refraction is on (refraction is not black) and the ior set to the volume is the glass ior. Corey and I are working on re-evaluating our material creation based on the new information you provided us in that dlx file. Thanks again Vlado!

[joe_b]

material bugs in build 3

Ok I get it now, it's logical that when there is no reflection, there is no highlight either.

But sometimes the user needs highlight glossy only (without the need for time consuming real glossies), so that would mean refl glossy=1.0 and highlight glossy < 1.0.

For cases like this, it would be nice if options get grayed out when they have no effect in a given configuration (gijs mentioned this already I think).

Yes we definately understand this, some of the UI tweeking has been put off until other major updates get in but dynamic updating based on setting states will be in hopefully by the next release. Also as I said in my previous post responding to Vlado, we are in process of reevaluating our materials. We are aware of the glossy issues. Thanks for your help flipside