Hey faustwolf, good question:
Generally, a high poly CG character would be quite a pain to reduce down to a clean in-game model. In this case, however, I've modelled a low poly (probably a bit more than 600 faces, but still in-gameable) mesh and worked off of it. In other words I used techniques like
displacement mapping (
http://en.wikipedia.org/wiki/Displacement_mapping) to add the necessary detail for a CG quality model while retaining the ability to roll back down to a lower poly one without ruining everything. If I meant to make an in-game model from the beginning, though, I probably would have done many things differently - but it is possible in this case.
As for keeping detail in a low poly/game model, it's also quite possible to retain almost all of the detail in the model I made in a very low poly one with
normal mapping. Basically, applying a normal map to your low poly model tells the game engine/3d software how the light and shadows will react to the model in a much more complex way than the simple polygonal structure would indicate. See the following pictures to see the effect that applying a normal map could have on a low poly model WITHOUT adding any polies/vertices/faces:
http://www.computerarts.co.uk/__data/assets/image/185268/varieties/7.jpghttp://www.3dkingdoms.com/nmap.jpgAnd here is how a normal map actually looks:
http://folk.ntnu.no/eigilh/bilder/assassin_normal_map.jpgIf you remember my explanation about UV mapping in the last magus thread, then you will realize that the same concept applies to normal and displacement maps. Normal maps use color value to indicate how far our or in the light and shadows should read on your model, while displacement maps use greyscale values to
actually change the mesh (
http://www.fantasylab.com/newPages/rhinorkD.gif). Note that before using displacement maps, the modeler always subdivides the base mesh for more polygons so that it displaces more accurately with more detail.
I ended up using displacement maps to add the facial detail and muscle structure off the base mesh to produce a cg level character, although had I used normal maps instead, the detail would mostly be there and the polies would still be a very low count.
SO - normal maps don't increase polies but add good detail, and displacement maps add lots of polies, but add incredible detail.
Sorry for the novel.
