render with alpha channel

hi there, i need to make a render but i want the render have alpha chanel, for example, i render a model, and then export the image, to gimp or photoshop and there, all is transparent except the model

Use Premul or Key in the Render tab in F10 and RGBA in the Format tab.


doing as u said i obtain the opposite efect, the alpha informacion is in the model, not in the “around” in the attach shot, u can see the effect i obtain. i want to do just the opposite.


well, now it works i try again, but now i used png instead of targa, and works fine with png, thanks again

Yes, you must output to a file-format that supports the presence of an Alpha channel. Not all of them do.

… but targa does…

White stands for fully opaque and black for fully transparent in any program in know…so the image is perfectly correct, it will work as layer mask as expected.
But AFAIK Photoshop does open PNGs with alpha differently, as background layer being transparent rather than having an extra alpha channel like all other formats. Ask Adobe for this inconsitent concept…

in this case, not work exactly as you said, i explained, when i obtain the image show in the screen shot, i paste in a new image with an rgb background, and no transparency apear but i have an alpha chanel, using png format (i know targa work with alpha too) i have the monkey, with a board chess like background (notice in photoshop this is transparency) and when put this image over another work fine, i discover its a problem only in photoshop, with gimp work ok, tga or png. i supouse, photoshop work fine with tga too, maybe the problem is when blender export to tga and open with photoshop.

Lol thanks
That will help me with my game sprites :cool:

It works exactly as he said. Since PS CS (as far as I can remember) - which you’re using, judging from the screenshot - you have to apply the alpha channel for .tga’s manually. It doesn’t automatically show the transparency after you have opened the image file.