MentalRay and Auxiliry Channels for using in Digital Fusion.

[Kman3d]

Hi,
I am wondering if it's possible for MenatlRay, to save additional Channels in a File, or perhaps different channels as different Files...

I'm trying to Generate a UV channel that stores the coordinates of the UV texturing from Maya..
So I can use it later in Digital Fusion for Texture replacement with the Texture tool... (something like 3DS MAX RPF format)

UV data Generation is pretty simple: U & V channels are simple B&W gradients...
I've Partially accomplished the effect using Maya Renderer,
I connected a B&W Gradient Map to R channel, and another B&W Gradient to the G channel of a surface shader in Maya. (The B channel was connected to black color)... I then applied the shader to an Object and rendered it.
In DF I use the Channels Booleans tool to copy The RG (without the B) data to UV channels. And finally I apply the Texture tool.

The trouble is that after Rendering, The Rendered image and textures are Filtered, what makes the gradients to be like "Pixilated" or jaggy, and that leads to a poor texturing in Digital Fusion.
So I've turned out the Filtering Option inside Maya, but it still not a pure Gradient after Render... (the data should be like Z-depth data or like Max's RPF data - not filtered)
Another Problem is that I loose the RGB data of the whole image in that method.
For instance I have a bottle with a label on it, and I only want to replace the label texture inside DF. If I apply the above shader to the label and then use channel Boolean in DF, it copy's the whole R and G data of the whole image (Including that of the bottle). So That's another Problem…
But also I found a partials solution.
The solution is again to apply a surface shader with a Unique Pure Color to the Label and different Colors to the rest of the image, And use that data inside DF as Object ID to mask the Label out… (and then finally to merge all that together). It's also possible by Rendering only the Label and use it's Alpha channel as a mask, but it no good if different textures are applied to diffrent parts of object...
but the Alpha's Edges are also filtered what makes it impossible composite it with good result later...

All that sums in multiples renders and texture changes inside Maya, (Much Time consuming) and the result is not perfect and no suited for production…

So I was wondering if such effects are possible with the MR renderer in maybe a simpler way, and is it possible to save separate channels to (like Object ID) different files? And render all of the above in only one render pass…
Sorry for such a long post,
Thanx for any Help…

Guy.

[Kman3d]

O.K maby any one can explain to me how to use Frame buffers in MentalRay, and how to set them up...