AlShader IDs equivalent or workflow in V-Ray

[AlexOddbratt]

In the alShaders for Arnold the alSurface shader has 8 custom ID slots with matching aovs/render elements that can be used for any number of things like rgb mattes, custom textures, occlusion aso on a per shader basis and it's a invaluable feature that's missing from the
V-Ray alShader implementation.

So my question is basically if there's a way to achieve the same thing in V-Ray?

What I'm looking for is a way to on a per shader basis connect or link to a bunch of hand painted textures/masks that then get's rendered out to custom elements. For example ID1 is a texture that's painted to mask the inside of the mouth on shaderA, ID2 is a mask for any "dirt" on shaderA
while ID6 is is a painted RGB matte for different sections of the body on both shaderA and B. ie per shader masks that can't be achieved through object ID or multi mattes.

The only options I've found that's going in the right direction seems to be "Material ID" or "Extra tex" but they are severely limited as "extra tex" assigns the same texture to all objects in the "include" list and not different textures on a per shader basis
and "Material ID" seems limited to 1 texture per shader making it unusable in this case.
Is it perhaps possible to have multiple "Extra tex" elements write to the same "name" ?, so that I in principle could create one "Extra tex" per shader and ID.

Any type of workflow to solve this issues would be highly appreciated as I'm guessing that it's going to be a while until a "proper" alShader with all the bells and whistles is implemented in V-Ray.

[vlado]

The only option for now is the VRayExtraTex render element. There are a number of ways to vary the texture depending on the rendered node and what kind of texture it is.

I doubt that we will be implementing these particular options of the alShader material. We will probably look for an implementation that works for all materials.

Out of curiosity, how does this workflow happen in Arnold 5 were you don't have the alShader?

Best regards,
Vlado

[AlexOddbratt]

That's a shame as the ID part of the AlShader was one of it's best features and so easy to use, automate and build a pipeline around.
I haven't played around with Arnold 5 so I don't know how it would be solved there.

I think the main issues with the VRayExtraTex render element is that they can't be daisy chained at the moment. If I have multiple ones that all write to the same element name they will override each other instead of combine.
The preferred approach from my point of view would be to have one VRayExtraTex that assigns TextureA to an inclusion set that contains ObjectA and renders it to layer1.
Then have another VRayExtraTex that assigns TextureB to include set ObjectB but still renders to layer1 and since the two include sets don't overlap it should combine and get one image that has two different textures,
but the way it works now is that it assigns the texture to the include set but then also assigns "black" to everything else therefor "overriding" any other VRayExtraTex that writes to that element.

So I would basically have to have one element per texture per object which would end up being a tonne of extra layers that all would have to be manually setup.

[vlado]

You can use a switch texture to put different things on different objects, or V-Ray user attributes, or any combination of them. Would that work?

Best regards,
Vlado