multiple refraction layers

[Matt_cg]

Re: multiple refraction layers

In reference to the brazil render (please don't yell at me :-[ ), there is one thing that would be great to duplicate. If you notice that on some of the facets have multiple colors blended on one facet. So far, I have only been able to get a single color to show on a facet. Does that make sense? For example, if you look towards the upper right of the stone in that render, you will see a facet that blends from yellow to red. Is something like this possible?

Matt

[Matt_cg]

Re: multiple refraction layers

Well, I think the colors are getting to be more where I want them. However, I've noticed something else that I'm having trouble with. The facets on the front of the stone should, in my opinion, have more of a highlight. Right now, they seem to be too transparent. I have been playing with the amount of reflection, but there is a fine line between not enough and too much. :P

I will keep playing, and hopefully have some decent settings to post.

[dalomar_cg]

Re: multiple refraction layers

I agree that the front facets should be more visible. I would say that the easiest way to tweek that is by changing the minimum reflection layer within the fresnel settings (Reflection layer> Reflection Map) and change the black color to a dark gray-ish color. That and also making sure that the two IORs in the fresnel settings are the same is also important (some people only change the fresnel IOR and not the refraction IOR as well)

[Matt_cg]

Re: multiple refraction layers

Damien, thanks! I think I have the color set to a gray already, but the IOR's are different. I'll keep my fingers crossed.



Also, I gave something different a try. I added a second reflection layer, and removed both fresnel maps. I tweaked the reflection / glossiness from there. Here's what I got, but still not wonderful.

[Travis Serio_cg]

Re: multiple refraction layers

I agree that the front facets should be more visible. I would say that the easiest way to tweek that is by changing the minimum reflection layer within the fresnel settings (Reflection layer> Reflection Map) and change the black color to a dark gray-ish color. That and also making sure that the two IORs in the fresnel settings are the same is also important (some people only change the fresnel IOR and not the refraction IOR as well)

Hey Damien, This might be a silly question but here it is anyway.

Where is, or what is the determining angle vray uses for the fresnel layers. Meaning, in most apps we have control over perp to camera or perp to a UVW or just a specified camera angle or global angle. What is vrays determining angle? It looks to be perp to camera? If so, can we change the determining angle? I know that a variance in IOR will control the specular values of the fresnel reflections, but is it possible to adjust the min/max angle in which the two layers merge and split?

[dalomar_cg]

Re: multiple refraction layers

Right now the only determining factor in the falloff as far as the angle goes is the viewing angle. And unfortunately there isn't a way to adjust or change any of that . Joe has been meaning to write an advanced falloff texture that would provide a lot more functionality and allow us to do all of the things your asking for.

As it stands right now, all has to be done through adjusting the colors and the IOR values, and there's really only a certain point where that works. Its very view-specific, and its takes allot of fine tweeking.

[Travis Serio_cg]

Re: multiple refraction layers

ok thanks. I had figured that was the case from our experiments, but i wanted to make sure i was not overlooking something.

[Matt_cg]

Re: multiple refraction layers

Well, I've been having a really hard time getting the highlights to show up on the front facets. This is another one with dual reflection layers (it seems to get me closer). Now, I have to find the balance between the highlights and the cloudiness of the stone..... too much reflection = BAD!!

;D