Top Bottom and Shellac Materials

[FaustoDeMartini]

I would love to see new materials that mimics the Max Top Bottom (super useful for terrains and is very easy to use) and the Shellac, that allows to create a Carbon Fiber effect very easily too since you can control a separate material for the surface and another one (with different types of bump, reflections) for the material underneath.

I know that are probably ways to get similar results with what is available but I'm not looking for a over complicated process to get to a result that could be easily achieved with a proper shader.

[joconnell]

Shellac is kinda the vrayblend material with one layer and I want to check out the falloff material on GPU (my trial expired, will check it in work if I can) which has a towards / away mode which you can set to world or object z direction - it'll give you the upwards facing direction of any surface as a black and white mask which is doing what the top / bottom shader does too. Which build of vray are you on and cpu / gpu?

[vlado]

What joconnell said - use V-Ray blend material with different masks - usually a Falloff map in some mode.

Best regards,
Vlado

[FaustoDeMartini]

Shellac is kinda the vrayblend material with one layer and I want to check out the falloff material on GPU (my trial expired, will check it in work if I can) which has a towards / away mode which you can set to world or object z direction - it'll give you the upwards facing direction of any surface as a black and white mask which is doing what the top / bottom shader does too. Which build of vray are you on and cpu / gpu?

Thanks for replying! I was trying to use GPU but ran into the limitation of Max shaders (that I use often) not being supported then switched back to CPU. Do you know any documentations that can show these methods you described?

Again, my point is that is great when we have materials ready to use that don't require a time consuming setup to get what we want. Specially us 3dsMax users that are use to the shaders Max always offered.

I do assemble complex shaders on my own, but my point is that if vray doesn't support a particular max shader, they should offer a vray replacement for it.

[joconnell]

Will get you on fb and we'll sort it out

[FaustoDeMartini]

Will get you on fb and we'll sort it out

Sounds good, thanks a lot!!

[^Lele^]

Oh, but this could well prove interesting to the general public!
FaustoDeMartini 's gripes are valid, and we old V-Ray users may have a bit too much ease in the "translation" from old Max, enough to make it sound nonsense to newcomers (of V-Ray. I wouldn't dare, Fausto. ^^).

As joconnel and Vlado well said, your go-to material is the VRayBlend shader.
VRayBlend is a multi-layer, maskable, stochastic and multi-operation shader.

It can have up to 10 layers (base + 9 coats. Recursive if one so wishes, with a blend into a blend, into a blend...).
It's maskable, as all layers (but the base one) can have a mask determining their influence on the result.
It's stochastic in sampling, so that adding layers will not add computation time in a linear fashion: three or six layers take the same amount to be sampled (crucially, not to render! that will depend on the materials in each layer, of course.).
It's Multi-operation, as a single checkbox will make it a mix, or an add, between layers.

So, back to your initial questions:
*) Top-Bottom Shader:
V-Ray Blend at defaults, your two materials into the base and layer one, layer one has a Falloff map as mask, set up as shown (it's really two clicks. Unfortunately there is no maxscript access to shading curves' points, so this can't be scripted. I'd love to be corrected on this.).

Notice that you could add as many top and bottom shaders inside either the same VRayBlend (using the other layers) or in a recursive fashion, with a blend for the top and a blend for the bottom layers, and so on.
Further, notice you now have the whole latitude of the falloff map to choose what the reference, and direction/type of the blend should be.
Last but not least, it's trivial to save a simple setup in a material library for rapid re-use (again, i know of no scripting access to key parts of the shader, on the Max side, or i'd script you one.).
It being this simple to setup means it's unlikely we'll get it as a separate shader. There's always OSL, but i suck at it and can't quite find love enough for it to get over the few obstacles, so others may be more helpful there.

*) Shellac shader:
This is simpler still: your carbon fiber weave shader as a base material, and your reflective coat(s!) in the layers above it (below, in the VRayBlend UI. it reads top down.).
The only little trick is to tick the box which says "Additive (Shellac) mode".
You may choose to use a Fresnel term in the shader itself, or in the blend map (fresnel falloff).
I'd suggest using the VRayMtl fresnel approximation for better results.

As for any wholly additive shader, it's down to the user to ensure energy preservation (in other words, no sum of shader components should go above 1.0, or it would emit more energy than that which hit it).
For a carbon fiber with a clearcoat, the Specular may be the component at risk of going above 1.0, so f.e., you can set the specular for the weave at 25% gray, and that for the coat at 75% gray, and that would work.
This stuff can be scripted, with the caveat of maps, so i'd still go for a material library save of a preset.
Here too you're not limited to one coat layer, which should have you cartwheel in joy the second you'll start playing with the Blend. ^^

[FaustoDeMartini]

Lele, in the first place, thanks SO MUCH for taking so much of your time to write all these detailed explanations! Super great info and I will follow your explanations to setup what I need.

I agree that the Vray Blend is awesome and it can be used for everything I'm looking for. My point is, Vray is getting a harder competition from other renders recently (in which I tried some of them) and I have to say, they do feel a bit more straight forward to use. I still prefer Vray for the capabilities and amazing results, plus how it handles tons of geometry,etc.

But I feel that we could inject a bit more of basic materials that are use to plug and play. As an example, I played with Vray Alsurfaceshader recently and had a bit of a hard time getting to behave like the Vray Skin Shader. To me eliminating the Skin Shader and leave the more complex one to setup is totally going to the opposite direction I was referring above. I'm attaching the result I got using Vray Skin Shader, and I could not reproduce on the AllSurfaceShader for some reason.

https://forums.chaosgroup.com/forum/...lsurfaceshader


I don't think we are asking for much really I think is awesome that we can get under the hood and do tons of very complex shaders, but is also great to have a balance of ready-to-use/simpler-to-setup shaders in vray.

Just my two cents


-Fausto.

[^Lele^]

Ah! you're most welcome, and surely i didn't mean to say we *shouldn't* have more shaders!
The balance between piece-wise (f.e. VraySkin being 3 x fastsss2) and ubershader (AlSurface) is a fine one, and providing for both isn't easy a task.
It's also something we continuously evaluate, however, and there may be some news in that department soon enough.
So thank you for the feedback, it's surely taken into account.

As for removing shaders, i'm personally only in favour of hiding, but leaving them as creatable at least through scripting, but i do not make the calls, thankfully. ^^
I could probably make you a VRaySkinMtl clone, if i understood the way it was built originally.
Or we could petition for it to return, if it wasn't a terrible technology breaker for Next (oh i love getting into trouble!).
Will ask.

I'll say nothing of your render, you probably have heard it a few times already.

[FaustoDeMartini]

Haha you are too kind Lele, thanks so very much

I believe the Skin Shader is currently hidden and can be called with a script. I agree with your points my friend, I think is all a balance in providing great shaders that can be turned into very complex ones and having some ready to plug and play shaders since quite a bit of the user base is probably attracted to easy-to-use solutions

I love the work Chaos does and how much Vray evolved on the last releases, I'm just trying to be a Devil's advocate in this type of topic!

Thanks Lele!

-Fausto.

[^Lele^]

I believe the Skin Shader is currently hidden and can be called with a script.

Unfortunately is non-creatable: i did try, and fail :P

I love the work Chaos does and how much Vray evolved on the last releases, I'm just trying to be a Devil's advocate in this type of topic!

When properly argumented, there's little beating the value of critique, as i'm sure you know... ^^
Keep'em coming!