How to?; Alpha lighting ( negative shadow)

Ric · October 13, 2006, 8:14pm

I’m making some images ( with alpha channel) that a game engine will use over various other images. They use the alpha channel for shadows and translucent objects ect… Now I’d like to make lit objects like fires with a lightening effect in the alpha channel. Is there a way to make a shadow lighten instead of darken? ( For eg, the attached image with the shadow under it R100, G100, B0, A160 )

Attachments

jackblack · October 17, 2006, 1:55pm

Hmm… Good question. I think you’d have to use either the node editor (which I know very little about) or maybe edit it with a 3rd party app or render the shadow seperate and invert it? I’m not real sure, I’d just use a lamp for the light that those objects would produce.

pikseli · October 19, 2006, 4:36am

shadow that lightens is light.

BeefotronX · October 19, 2006, 1:21pm

EDIT: Okay, here’s something like it, maybe.

In the example picture:
The plane under the object has an alpha of about .5.
There are two lights: one hemi , and one spotlight set to negative.

(The object was inspired by the pivot tutorial from BlenderNewbies)