The "lt_grp" are a pain to figure out to start with, but basically every single item has it's own light source or "lt_grp", in the case of the one I'm working on atm there's 32 of the bloody things. lt_grp=9 is usually for the main room model or 'scape and it can have a couple of seperate lights, L_DIRECT for the main light and L_POINT for spot lighting something. In the case of a 'scape lt_grp=23 is used for the sky dome, that leaves lt_grp's 0, 3 & 10 for me to still figure out and I'll get back to you on them once I finish converting this planetscape from day time to night time.

**shuffles of with a new headache**

Well, lt_grp is actually very easy to do. You can define it for every room, prop or character. Those objects will then be lit by all lights of the same group. I found out that way that it is easier (and less confusing) to use the same lights for people and the room itself (though I've tested this in only one room and this might vary according to the look you want to achieve).

I've also figured out a few other things tonight, like the type for instance. It seems to be named after the method the light is spawned at the source. If you'll take L_DIRECT, for instance, there'll be "light rays" all along the axis you defined. (This also explains some strange lightning I experienced while using this type.) L_POINT, on the other hand, will create the light from one point in every direction, more like a conventional light.

Then there's atten, short for attenuation. This seems to influence how bright the light is and how far it is visible. My knowledge here is fragmentary, but it seems like the first value defined light intensity at the point of creation (it acts as a factor to some hardcoded value), while the third value somehow seems to define how quickly light intensity diminishes away from the source. (It's somehow influenced by "range", too, so I think it is again a factor.) I am currently trying to figure out the third one. And I have no idea what the second one does. Also, during all my experiments, cutoff and theta had no effect, though I know they are varied in some scripts (like in my reference, the Manhattan bar). Specular doesn't seem to have any effect, either.

Any help would be appreciated.