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Alpha Question

Posted: Wed Jul 06, 2011 10:58 am
by AndreD
Hi,
just hava one question:
I need an embedded alphamask of one object but there is no option like in c4D to render selected objects only..
If I hide the background objects, they are not take part of the gi-calculation / reflections..
On option would be to use material ID or object ID but I won´t get an embedded alphachannel and I have to render an animation..

Any ideas? ;-)

All the best,
Andre

Re: Alpha Question

Posted: Wed Jul 06, 2011 3:30 pm
by brodie_geers
hrm...maybe you have another engine that could render out only the alpha mask?

Or perhaps now that we can customize the material ID colors you could set all the other materials to render with a black mat ID, apply apply a single custom material over your object that's set to render with a white Mat ID. Either would require a totally separate render pass but it's an option if you have time

-Brodie

edit: I don't think mat ID has aliasing so you'd have to be willing to sacrifice that - hopefully not too noticeable in an animation.

Re: Alpha Question

Posted: Wed Jul 06, 2011 11:50 pm
by Mihai
You mean anti aliasing? All channels should have that :)

Maybe the matte option for that objects material would do what you want? Or actually.....set the matte option in all the materials for the other objects. If your background is black you'll just get your object rendered against a black background which you can knock out, and even obscured by the other objects in case it passes behind one of the other objects.

Re: Alpha Question

Posted: Thu Jul 07, 2011 4:39 pm
by AndreD
thats it :D