Rough Specular reduces specularity amount?

[vlado]

You have Beckmann brdf in the ALSurface MTL. I'm wondering if this something which also exsists in the Vray MTL under a different name or is it different from what we allready have?

Nope, it's not anywhere else. The alSurface material is the only implementation that we have right now.

Best regards,
Vlado

[instinct]

Why is that Thorsten?

Because i think it clutters the UI and will hardly be enough. For a lot of things we work with 3 layers, and bam you have UI clutter and still resort to VRayBlend (we are also using VRayBlend for other reasons, but still). And i think it makes a lot of assumptions on specific use cases. I'd prefer it to be the generic lean mean machine that it is.

Cheers,
Thorsten

[sharktacos]

Because i think it clutters the UI and will hardly be enough. For a lot of things we work with 3 layers, and bam you have UI clutter and still resort to VRayBlend (we are also using VRayBlend for other reasons, but still). And i think it makes a lot of assumptions on specific use cases. I'd prefer it to be the generic lean mean machine that it is.

Cheers,
Thorsten

That makes sense. Don't want a pandorora's box.

[sharktacos]

Vlado if the idea of the material's built in Fresnel-transparency is to get it to blend properly, wouldn't there be an issue when someone adds 10 of these dudes to blendMtl? Would we need to have an option on the blendMtl to normalize the result so it does not break energy conservation? or is there some other way to address that?

[Morbid Angel]

transparency is not additive, so the top material will overwrite the underlying one. Unless some one uses the additive mode, it should be fine, but I'd still vote for this to be a separate material rather then a vray mtl option.

[sharktacos]

transparency is not additive, so the top material will overwrite the underlying one. Unless some one uses the additive mode, it should be fine, but I'd still vote for this to be a separate material rather then a vray mtl option.

My understanding is that the material's reflection would be multiplied by the Fresnel (that happens in the material), and then that could be combined with a blendMtl in additive mode. So you could have as many spec layers as you want, and each would use its own Fresnel transparency. The issue is that as more and more are added, we lose energy conservation.

[vlado]

My understanding is that the material's reflection would be multiplied by the Fresnel (that happens in the material), and then that could be combined with a blendMtl in additive mode.

Nope, no additive mode! The Fresnel would need to properly dim the contributions of materials below the reflection layer.

Best regards,
Vlado

[zeronove]

mmh, maybe I will be alone but let me say for me it will be better to add this option to VRaymtl.

As I understand it's not an option or an alternative but a core feature of real material that was someway missed previously.
I don't like the idea of VRaymtl 1, 2 or whatever and about the UI ...I don't think it will be messed up adding a checkbox; if yes, I will suggest to rework it a bit ...nevertheless for new user it will be more clear where to start: VRaymtl ...period
An envelope mtl (ala 2sidedmtl) could be an option but the shader network will be a level higher just for that so I still prefer the previous one.

Obiouvsly I don't know anything about the technical side (ex. render speed, complex coding etc.)

[sharktacos]

Nope, no additive mode! The Fresnel would need to properly dim the contributions of materials below the reflection layer.

Best regards,
Vlado

So (1) would it be possible to combine this new material with a vrayMtl which has its own spec, and get 2 spec lobes?

Further, (2) would it be possible to layer multiple instances of this new material to get, say, 3 or 4 spec lobes?

[vlado]

So (1) would it be possible to combine this new material with a vrayMtl which has its own spec, and get 2 spec lobes? Further, (2) would it be possible to layer multiple instances of this new material to get, say, 3 or 4 spec lobes?

Yes to both, of course. Otherwise what would be the point...

Best regards,
Vlado

[Midiaeffects]

As sharktacos pointed out, a simple texture map will not work accurately. I'm still trying to figure out what is the best thing to do in that case. I have two options:

a) Add an option to VRayMtl to ignore the diffuse and refractive layers and use the Fresnel transparency of the reflective layer as transparency for the whole material. In that case, if you put it as a coat in a VRayBlendMtl material with full blending, without any texture map, it will automatically blend things correctly.
b) Create a new VRayGlossyMtl material that only contains the reflective portion of a VRayMtl material with the Fresnel transparency as transparency for the whole material.

Which option do you prefer?

Best regards,
Vlado

Vlado, "option a" seems like a refraction option many renderers use for window glasses made out of single sided polygons. In other words it's just a simple opacity without refraction. i.e Corona has a "thin" option for refraction, mentalray/Iray Arch & Design have a "thin walled" option, Maxwell have an Architectural Glass and so on. What I mean is that maybe a solution is just to add "Thin" option for refraction too.

-Eugenio

[vlado]

Vlado, "option a" seems like a refraction option many renderers use for window glasses made out of single sided polygons. In other words it's just a simple opacity without refraction. i.e Corona has a "thin" option for refraction, mentalray/Iray Arch & Design have a "thin walled" option, Maxwell have an Architectural Glass and so on. What I mean is that maybe a solution is just to add "Thin" option for refraction too.

On one hand, this is true. On the other, it's very non-obvious that you would use this option when layering reflective coats, isn't it?

Best regards,
Vlado

[Midiaeffects]

For that purpose it's not super intuitive, I agree. In that regard, I would rename "option b" from "VrayGlossyMtl" to "VrayCoatMtl", seems to make a lot more sense to me. That's the purpose of the material anyway. Also, a wish/suggestion for VrayBlendMtl is to add an "Add Coat" button which applies a VrayCoatMtl, or maybe a VrayMtl properly setup for coating, with white refraction color and "Thin" option turned on. Like this:



-Eugenio

[sharktacos]

Yes to both, of course. Otherwise what would be the point...

Best regards,
Vlado

Hehe, that's what I was thinking too. Thanks for clarifying.

Would it be layered using a blendMtl, or were you planning on making it like the bumpMtl (with a base material input)?

If the idea is to use a blendMtl to combine it, what would prevent a user from turning on "additive" mode in the blendMtl? I imagine a lot of people would intuitively assume that they should. Also they would need to make the blend amount white (100%) instead of the default grey (50%) right? Seems there's lots of potential for incorrect usage with the blendMtl (in Maya anyway).

That's why I'm thinking having the new material have a base material input might be more intuitive. Like this (this is in Maya, sorry I don't have Max):

[Ihno]

Hi,
will the VRayGlossyMtl be included in the beta 2? I'm missing it