Okay, so I've just learned a lot about Normal maps in the last little bit, because I realized I didn't understand them at all. I've been reading through and learned there are all sorts of Normal maps. So what kind do you suggest using? I've never noticed any blue or rainbow colored stuff on any of the materials I have, so do people usually use greyscale normal maps? Or have I just not been paying enough attention?
There is a lot of confusion around the differences between normal and bump maps. I've noticed that during the early release of Poser 11, where even some big names from the content creation crew were misunderstanding the difference. Normal maps are a much more recent invention, and maybe that's why there is some confusion around it.
Bump maps are the old way of adding fake detail to a surface. They are limited to 8-bits resolution, which can only reach up to 256 levels of grey. When adding fake detail to a surface, bump maps only understand "up" and "down", and it only works if the camera is looking more or less straight to the surface, since the added details only exist in shadow casting. They are easier to create than normal maps because all they use is 8-bits greyscale, which can be painted in Photoshop.
Normal maps are the better and newer solution, where it uses the RGB values of a bitmap to store X, Y and Z coordinates that are used to calculate normal vectors out of each pixel (hence the name). These vectors are then used to calculate the shadows in actual 3D space, instead of just up and down. This is the most used method in real-time games nowadays because of the added detail and performance, but just like bump maps, the details are also fake and only exist in shadow casting. There are 2 kinds of normal map: local and tangent space. Local is the default in Poser, and it only applies to models that don't move, such as props. Tangent space is the bluish-purple one, and it's the best choice for models that move (deform), such as characters and clothing. Unless you are mapping a prop, you have to remember to change this setting in Poser to tangent space, and set gamma to "1" instead of "2.2", since these maps don't need color correction. If you forget to adjust gamma, the normal map will appear overblown.
Besides bump and normal "fake" details, there is also displacement. These actually change the models surface during render time, and require a compatible mesh resolution to be able to do so. If the geometry doesn't have enough polys, it will be of no use. Displacement maps use the same kind of greyscale maps like bump maps, but are much more computationally expensive, and require high-res models to work. Conversely, bump and normal maps add "fake" detail, so they are very fast to render and can be used with low-res geometry - hence the best choice for game engines.
Hope it helps avoiding confusion. ^^
