BF2 uses a formula where 1 pixel = 1cm in-game. Therefore when you unwrap objects you should take this into mind.
Vehicle Bodies: If a body is 7 meters long then don?t unwrap its UVWs to a 300-pixel space, at medium resolution. You?ll be looking at a blurry mucky mess. Instead unwrap it to 700- pixel space. Things that are not seen regular can be map to a much smaller space. They don?t need to hold to the formula as much, as they aren?t seen as much.
EX: Underneath or semi-hidden areas, the bottom of a turret, and so on.
Wheels: I would suggest making them a little bigger then the formula, so u can get a nice texture on them as there are usually a lot of these on a tank and can be seen regularly.
A lot of this is common sense. If a mesh takes up 75% of the model then for heaven sakes, don?t unwrap the UVW's to 1/5th of the allotted UVW space.
An example of the formula at work:
http://204.11.239.71/dfast/ukrTnk_Oplot_c.jpg
Here is the break down:
1. Bumbmap creation
2. Specularmap creation
3. Colormap creation
4. Shadowmap creation
Bumpmaps are just grayscale images that control height in a render, where as white would be the highest point and black the lowest.
The difference between bump mapping and normal mapping is that bump mapping uses grayscale, and normal mapping using RGB. However, you can make a normal map using a bump map.
Bumpmap:
http://204.11.239.71/DFast/Tuts/Oplot_Bump.jpg
Yea, basically think of specularmap as a non-painted vehicle. Like it just left the factory floor ready for the paint booth ? ?Bare Metal?
http://204.11.239.71/DFast/Tuts/Oplot_spec.jpg
Both my bump and my spec are all created in Photoshop in the same document.
I use my bump mapping to get exact placement of the finer details u see once it?s skinned.
Now here is the biggest reason why I do it like this - "camo"
Once all the details are in these beginning spec process u can start laying down color using the layer blend modes in Photoshop.
Of course one can always add finer detail on top the color layers to make them pop a bit better.
I generally will use a soft white on top of my color layers with a blend of luminance or what ever called.
http://204.11.239.71/DFast/Tuts/PSD_Overview.jpg
Generate shadow maps in your 3D program and save them to import for the model.
Now the specular map controls the shine as u know, so once the vehicle skin is completed, I turn off the color layer and bump layers, then I do a curve adjustment to that folder.
http://204.11.239.71/DFast/Tuts/Oplot_spec_final.jpg