PDA

View Full Version : blend mode for light pass?

Deniss
10-21-2006, 01:45 PM
Is there a a blend mode, that would properly combine "light pass" and "color pass" renders. None of the existing photoshop blend modes can do it. Looking for a way to render light and color separately, and combine them without any strong adjustments, to get the final resoult. Is there a specific sofware for that?
Thanks
payton
10-21-2006, 05:41 PM
try overlay, add or screen.

good luck,
payton
scrimski
10-21-2006, 05:49 PM
Have a look here (http://www.3drender.com/light/compositing/index.html), it's a simple compositing in a PSD-file with the right blend modes.
Deniss
10-21-2006, 06:06 PM
The example already has light in the base layer. Looking for a way to render textures separately.
payton
10-21-2006, 06:15 PM
The example already has light in the base layer. Looking for a way to render textures separately.

what are you searching for? a layer with no light in it will be a black solid. do you mean ambient light only, no shading at all?

the blending modes u need to use depends on your renders. f.e.: overlay only works well with light layers that hava alpha channels, otherwise the bottom image will get darkened to much.

show us your layers and help will be much easier.

payton
jeremybirn
10-21-2006, 06:24 PM
The example already has light in the base layer. Looking for a way to render textures separately.

If you mean you're rendering lighting as grayscale images (or with plain white lambert shaders on the surfaces during the lighting pass), and then textures rendered separately in an ambient pass, then the way you put them together in Photoshop is with a "Multiply" blending mode.

-jeremy
Deniss
10-21-2006, 09:19 PM
-jeremybirn
but how do you deal with overbright values on the surface.
Would be nice to render a plain GRAY lambert shaders and somehow combine it with an ambient pass in photoshop.


-payton
light layers that hava alpha channels? how is that?
jeremybirn
10-22-2006, 03:36 AM
-jeremybirn
but how do you deal with overbright values on the surface.
Would be nice to render a plain GRAY lambert shaders and somehow combine it with an ambient pass in photoshop.

gray/white whatever, I'd multiply. Brightness adjustments may also be needed. I hope if you are rendering at 8-bits a channel (not HDRI) that you are lighting carefully to avoid clipping at pure white.

I hope you can post some images soon. There are a lot of people here giving feedback, but we could be telling you the wrong thing for your situation if we can't see the passes.

-jeremy
CGTalk Moderation
10-22-2006, 03:36 AM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.