How to render transparency/layer mask for post editing in Photoshop?

[chearner]

I'm rendering a planet, and want to know how to render a black/white transparency/layer mask of the same scene to use as a in Photoshop. Basically the black space in the background I will want to show thru as a layer in PS.

I can convert a layer to B/W but rendering a true mask would give better results I'm sure.

[red_planet]

Have you checked the alpha files that are created when you render the image.?

You can find them by selecting Explore temporary files from the file drop down menu.

Hope this helps.

Chris

[chearner]

Perfect. Thanks, that is what I'm looking for. Didn't know they did that automatically.

[dandelO]

Also, if you want really quick access to the alpha(and RGB channel images, by the way) images just hit keyboard a,r,g,b, when the 'render view' window is open. Saves digging around in the temp' files and the R/G/B images aren't saved by default to the temporary folders.