First of all, whats the difference? apart from one is black and white while the other is a bluey colour...
Second, im experimenting using normal style maps with BZ2 in place of bump maps, does BZ2 automatically apply a bumpmap (if present) so long as an additional texture with _bump is present? Is that to ANYTHING, such as water tiles, terrain tiles etc?
Bump maps describe lighting effects. Normal maps actually effect the way mesh looks to make it appear to have more polies. I wish I knew how to make normal maps, but I suck at even getting a model with a high and low poly version, though if I scrap the UV I bet I could... and then convert the difference into a normal map if I can use only the UV of the simpler when doing it.
Normal maps are pretty easy to make (either via CrazyBump, or the normal map plugin for GIMP), i just wondered if using that in place of a bumpmap may make it work similarly, i tried it out on terrain, didn't seem to work.
Nielk if you are using 3dmax, there is a nice plugin called Polygon Cruncher that can make high poly models low poly pretty much. It's an easy way to make LOD models. I just found it recently for use on another game and it works pretty good. There is a free 7 day trial for the latest one. I have the version down from the newest one and so far it just tells me that the trial is up and some things are disabled but it still does everything I need it to.
As for normal maps, I played around with them a bit in Blender and they are pretty cool. It's amazing how they can make a completely flat plane look 3d. I also have a plugin for Photoshop from the Nvidia site that makes normal maps pretty easy. Looks like it is called Nvidia Normal Map Filter.