How do I get alpha and image from one render

[Brute Guy]

Greetings all,

 

This is something I have wanted to ask for a while. My normal procedure for obtaining an alpha channel is to render the shot with the floor in (vray plane) and then hide the plane and then re-render with active shade (for speed) and then select the alpha dropdown in the vray framebuffer window, to obtain my alpha.

 

I am asking if there is a way to obtain an alpha and the image in one render (i.e I don't have to hide my vray plane and re-render)

 

My initial thoughts is that maybe there is a setting to ignore the floor when it generates an alpha, but where are thou!!

 

I hope someone can shed some seeds of experience my way

 

Ta

 

Marc

[Chad Warner]

Right click on the plane, go to the vray properties and under "matte properties" set the alpha contribution to -1. That way it won't show up in the alpha.

[Nic H]

vray multimatte element! multiple masks (3) in one image.

search for it.

[Brute Guy]

Thanks both of you for your help, I now have twice as much time as I did have to render, which means I can surely go for a long coffee break now. Excellent!