View Full Version : "Radiosity Normal Mapping"

07-24-2006, 10:36 AM

I'm afraid the answer is "no", but maybe... I was wondering if there's a plugin or something that generate specialized lightMaps for a technique called "Radiosity Normal Mapping". This technique is used in Valve's Source engine (Halflife2), and described here:


Instead of creating a normal lightMap (with radiosity), like you can do with Surface Baker in Lightwave, it generates 3 lightMaps (in the same texture). Each pixel will get 3 light values, depending on what they call a "basis vector". For example, the pixel will have a value for all lights that affect from above, 1 for lightsources from the left, and another from the right.

Is there something for LightWave that can generate these kind of lightMaps? It would save me a lot of work and pain in the head!


07-25-2006, 11:38 AM
Heh, a few months back one of our coders (I work in games dev) asked me the same thing. I wasted half of the day trying to figure this out. Not much luck, I must say. **** it, Jim - I'm an artist, not a coder! ;)

(stupid censorship, grrr - I can't even quote Star Trek)

07-25-2006, 09:01 PM
Try this node graph. You'll need an object with a uv map, and as shown in the pdf there are image nodes for specular factor and albedo, and you'll also need to load an image for the specular map.

07-25-2006, 10:08 PM
I can read your graph Karma, but I'm still not sure what the end result of all this is... it seems to be distributing the illumination from three directions from the spot being rendered?

07-25-2006, 10:43 PM
Well ... I think this is what the shader is meant to do ...

Since it's for a game engine it can't do real radiosity, and instead they sample the light map in 3 different directions (based on the uvw coords). It's not very good as you can imagine, but it does give softer lighting.

EDIT: Also note that you should turn off self shadows because they cause havok with this shader :p