View Full Version : depth alpha?

08-08-2003, 12:35 AM
How do I generate an alpha map from the depth information in a scene (you know, where it's lighter closer to the camera, and darker further away?

thanks for any help,

08-08-2003, 02:20 AM
Well, you could do 2 things:

Add the Image Filter Render Buffer Export to your scene, set Source to Depth.

Then 1] either set Destination to Image File and the Image Type to LW_TGA24 (or another 24 bit file format your composite software understands) and choose a File Base Name,
or 2] set the Destination to Rendered Alpha, this way it will be replace the Alpha Channel in your image after rendering...

08-08-2003, 01:11 PM
thanks for the suggestion...I've been trying what you say, perhaps I'm choosing the wrong 'source' selections (tried 'depth' and a few others), but I can't get anything to show up, either with the rendered alpha, or the alpha channel in the rgb. i have turned the light off for diffuse, because i only want the light/dark in my alpha image to be an indication of depth, not a light source. So I know i won't get anything in an rgb image, but shouldn't the buffer still retain the depth to camera information? How can i get this to export to a grayscale alpha?

thanks for your help!

08-08-2003, 01:35 PM
OK, it seems to work only if I use 'rendered alpha' to a 32 bit file, and view the alpha channel of that image. It reverses the effect however, with the darkest areas closest to the camera. The 'negative' checkbox has no effect. But at least i I can invert it in photoshop.

much thanks for pointing me toward the solution!

08-08-2003, 03:57 PM
If you want to see these extra channels when you use F9, use Render Buffer View instead.