render elements - material

[J_man]

Hello,

Great! the VRay render elements are working! however, if I use a materialselect channel, I get the material on a seperate layer on teh background colour, just as the rendering looks when what I want is what scanline gives me, an alpha channel of the objects that are assigned the material.
This result isn'r really suitable for what I need. Is there another way or is this a limitation of render elements?

Thanks,

Josh.

[dimo]

Hi Josh,

this behaviour isn't a limitation, it's a feature! The material select can get very powerful if used with blendmaterials. You can split nested materials and render the partial materials to render elements.
What you want to achieve can be rendered with the wirecolor element. Set all Objects to black except the one you want to have in the alpha channel and set its color to red (255,0,0). You have two additional channels then which you can set objects to blue and green. You then have 3 "alpha channels" that can easily be extracted in your compositing software.

Best regards,

Dieter

[J_man]

Hi Dimo,

Thanks for your response! Yes, I'm aware of this technique to create alpha channels using RGB colours. This is laborious task though, especially if you have large amounts of objects and materials.
Currently I use my own script to add render elements using scanline, but this wont handle the new VRay camera, and wont do displacement, plus I have to convert the materisals to standard first, and there isn't a script converter for 1.5
I had hoped that now that elements work with VRay that I could do this all in one pass but it doesn't seem to be the case.

any ideas?

[dimo]

Hi,

I think you misunderstood me. You can use the VRayWireColor element and use the wirecolor of your objects. This way you don't have to change your materials and it will work with VRay specific things like displacement and the Physical Camera.


Dieter

[J_man]

Hi dimo,

No I do understand. It's just not quite what I want! I'm just kind of guy, I know what I want and usually, how to get it!

Cheers for your help dude

J.