PDA

View Full Version : object with no alpha channel



Philbert
09-25-2011, 11:19 AM
Is there a way that I can make an object render but not affect the alpha channel? I need to render this shot with a transparent background for compositing later but the gray back drop I'm using for the radiosity is affecting how part of the object looks when it dissolves out. So I though I'd just put a black object behind the main one. Everything looks great now but the alpha channel is messed up due to the background object.

patrickkelly
09-25-2011, 11:27 AM
Philbert, if I understand you correctly, you should be able to do so by selecting the object, go to Properties, go to Render tab, and in the Alpha Channel box, select Unaffected by Object, unless I misunderstand your needs.

Rabbitpenny
09-25-2011, 11:33 AM
Have you tried to render in "unpremultiply alpha" mode(Output Tab in Render Globals)? Is that what you need?

Philbert
09-25-2011, 11:43 AM
OK I got it, in the object properties, Render tab, I found the Alpha channel drop down box and set it to Constant Black. That seems to have done the trick.


Philbert, if I understand you correctly, you should be able to do so by selecting the object, go to Properties, go to Render tab, and in the Alpha Channel box, select Unaffected by Object, unless I misunderstand your needs.

Maybe that would work too.

@RabbitPenny Yes I was already rendering like that.