Alpha in World background?

Is it possible to select an alpha background in the World options? So that if I animate a scene, I can use the pictures as overlays in movies? The only thing I need to know is the alpha question, since I said that.


I think (don’t quote me on this) in your Scene buttons, Render panel, set RGBA rendering. Don’t know if the background colour matters.

On the “Render Layers” tab make sure that the “Sky” button isn’t active, activate the “Combined” button. This is only necessary if you are using nodes to render your scene. Otherwise follow Bakerman’s advice and everything will work out fine. I never render anything without an alpha background as I end up compositing almost everything I make in an external app and this is just good practice to follow if you want to save yourself countless hours of re rendering time when changes need to be made. Backgrounds can always be rendered seperately and recombined in the nodes editor with and alpha over node or recombined in the sequence editor via an alpha over effect (I don’t really use the sequence editor so don’t hold me to this last part). If you’re using global lighting this isn’t really an option.

I am currently working on a tutorial involving openexr files, z-depth passes and render layer passes which will hopefully save many of you from much of the agony that I am enduring while learning to work with these things. I hope that it will bring a much more flexible and professional edge to many a Blenderhead’s renderings when it is finished. I just wish I had more time to work on it.

Thanks guys, but one thing just. I’m working on my new computer where I haven’t installed Photoshop yet, so how can I tell if the background really is a transparent alpha?


you can check it by doing a render and then press left mousebutton on top of render, check number next to letter A=alpha, it shows how much alpha and hmm. actualy just press A and you see the alphachannel instead of render.