If the model shape matches the sprite pretty closely, it should work for anything we've got - though there's certainly some problems with using them as is :
1) The lighting is a composite of the sprite data, and uses a lot of painted on shadow. Therefore it won't respond correctly to the environment, or with real shadows, unless it's compensated for - effectively analysing the engine shadows and "unshadowing" the appropriate parts of the texture by an appropriate degree.
2) The pixellated textures are such a mess that doing simple alterations to the clothing (except colour change you showed) will be very difficult.
3) There is no way to generate an equivalent for any new object added to the game - that's all new armours and all the weapons.
4) They're pretty unusable as textures in any angle other than the 6 sprite angles (even falling over may look a bit odd).
5) Insides and undersides of things are going to be a problem
Anyway, if it's useful to you I can try and explain the process roughly. It was mostly a case of :
- Extracting 6 directions of relevant frames and resizing them to 400% (this saved some resizing time in the 3D program)
- Using
Fragmotion to load the idle anim into the base human, then export his pose as an "arms down" model
- Using
Crackart's texture painting mode to "chuck the sprite onto this model" from the correct angle and saving the resulting texture.
- Do this from all six angles for several sprites
- Put the layers into Photoshop to combine the six views (i.e. NE and NW have a good view of the back, SW and SE have a good view of the front etc).
The combining could have been done a lot better - I just did it quickly to see how it worked. Also note that Crackart crashes regularly, so if you've got an alternative projection painting software, I'd use that instead.
If you'll find it useful to look at, I could give a slightly better explanation with a few pictures to help, and give you some of the source files I was working with.
My "holy grail" is getting something which looks pretty much like these did, but is very easy to mod and overcomes the problems mentioned above. Previous bits mentioned about normal maps and filters might be the way to do this, but it's not an area I know a lot about.