I'm not going to go through all the specific parameters of each map, because many different combinations can work just fine and it is all a matter of trial and adjustments; you can look at the shading network chart I've made to get the general idea. My advice for this step is to add one map at a time, and always make sure you keep track of the contribution each map gives to the details. It sometimes helps to copy the specific map you are working on to a clean new material and apply it to the model just to check how it fits it.
- I often use an Ambient occlusion map as a mix map at the base of the diffuse colour for added depth detail. For the white colour I simply add the maps I was going to use anyway and for the dark colour I add some noise maps for "corner dirt".
Adding a mix level procedure and a few material editor notes
Before we go further, I just want to share a few insights about the material editor and explain the process of adding more and more details to an existing map - these things will be relevant for the next step.
General idea of the process of adding another mix level
So we have a nice base shader by now, but we want to start adding more specific details to the maps we already have in the diffuse colour
/ bump / glossiness / reflection colour. How can this be done?
The answer is to add another mix level to these maps and then add another mix level and another - there is no limit to this except that the more levels we add, the more complicated it will get. This is why it should be done in an orderly fashion, as follows:
1. Go to where the map you want to add a mix level to is located, right-click and cut that map. For example, if the map is in the diffuse colour slot then we go to the diffuse colour map slot in the base material (Fig.09).
2. Add a new mix map where your map was, right click on the map1 slot and paste your original map back. After this step your material should act the same as it did before; you've simply prepared your map for additional details (Fig.10 & Fig.11).
3. Add a black and white bitmap in the mask slot and name the mix map accordingly to the mask. For example, if you added a "blood stains" bitmap you should name the mix map "blood stains". Naming your mix levels will help you later on when the material starts to get complex. The black pixels of your mask represent where your original map will be and the white pixels represent the new colour2 / map2 (Fig.12).
4. Adjust colour2 / add a new map to map2 slot of the mix. For example - blood: in the diffuse colour
you might want to add a red noise map there; in the reflection colour
you might want to add that same noise map, but with a darker shade of red since the blood is dry and less reflective than the armour's metal; in the bump
map you might want to use that same noise map, but with bright greyscale colours since the blood stains act as outer dents (Fig.13 & Fig.14).
5. Go to the mask and give it a new map channel. This is the last step in the material editor. Since you're going to use several different masks you're going to need to use different map channels in order to create different UV's to map each mask separately. I'll explain a bit further about map channels next (Fig.15).
6. To add another mix level, cut the map in colour1 and repeat the process (Fig.16).