I still find it hard to not feel like im cheating when i create a texture with current gen technology, being able to bake out so much great lighting information and just layer over a few gradients. It's at that point i remind myself the workload has just shifted from painting diffuse, to sculpting . Not a bad trade off :)
To start your going to need nDo2 (link) to generate a cavity map in this section, it's possible crazybump or the nvidia filter can do the same conversion but i haven't given them a go in a while.
You should have six large images from xnormal,
Open your 1024x512 Normal map, load nDo2, and click the small convert button on the bottom of nDo2.
Then click Normal, Cavity and Active Doc
and you will have a cavity map that looks like this
Save the cavity map, and close your normal map.
At this point i create a new 1024x512 image which will be your master color map and start layering in all the baked images from xnormal, i start by creating a new group and calling it prt
Open both the prtN and prtP images, desaturate them by going to, Image -> Adjustments -> Desaturate
Copy both images into the newly created colour map, place them inside the prt Group with the prtP image set to screen mode with 85% opacity.
Open the Bent normal map, select channels, select the green channel and with only the green channel selected drag select the entire image with the rectangular marquee tool and copy.
Past the green channel you just copied into your colour map above the prt group, set it to soft light and only 9% opacity, i only needed this to be subtle this time around.
Copy the cavity map you baked in Xnormal and layer it above the BentNormal map, set to Overlay mode at 100% Opacity.
Copy the cavity map you made with nDo and layer it above the Xnormal Cavity map, set to Overlay mode at 100% Opacity.
Copy the Occlusion map and layer it above the nDo Cavity, set to multiply at 100% opacity
Duplicate the nDo cavity layer by going to Layer -> Duplicate Layer, and place it above the AO map, set to Overlay and 40% opacity
Now the important part, add a gradient MAP above the prt group by creating a new adjustment layer and selecting gradient map. Note make sure you use the gradient map and not the other gradient feature
Your image more than likely looks a bit funky right about now, fix that by clicking the gradient map bar to bring up the gradient editor. Take a look at the image below to see the gradient i used and the resulting metal effect, my advice is to fiddle with this for a bit, add nodes and move them around to see what you can come up with
Select the mask associated with the gradient map and paint black on any areas you don't want to be colored metal/grey. In this instance i masked the wood section of the handle.
Create a new gradient map above the metal gradient for the wooden handle, you will need to mask out all of the metal (inverse of the metal mask). Again please take a look at my gradient setup, this one turned out fairly crushed, ideally i should have adjusted the levels on the handle so i could spread the gradient out more - but it looks ok, will be covered in blood and pudges hand so good enough!
You now have a nice solid base for your color map, from here feel free to add whatever detail you want, i changed the values on the sharp part of the blade and some of the hard edges. To do this i created a few new layers in overlay mode with 50% opacity and painted flat white on the areas i wanted highlighted.
at this point im not happy with the side of the blade, it's a big flat area covered in mostly flat grey and not very visually interesting. To help alleviate this problem i use the gradient tool (not gradient map) to drag out a simple black and white gradient along the blade, which i then set to Multiply with 35% opacity. Mostly pretty subtle.
And that's it, a perfectly acceptable colour map.
Save the .PSD file to keep as your master and then size it down to 256x128 and save it into your final materials directory with a naming convention something like offhand_weapon_hacker_color.tga replace _hacker_ with whatever you plan to name your weapon.
Now that you have your final Normal and Colour maps, it's time to create the ever elusive mask1 and mask2.
If your having trouble understanding the mask images, i find the best way to think about them is, each image is actually four black and white images stacked one on top of the other, each performing a different task.
To begin with open the original two mask images that come with the source files, for Pudges offhand they are named pudge_clever_mask1.tga and pudge_clever_mask2.tga.
With one of the images selected click on the channels tab (nexto layers) and click through the individual R, G, B and Alpha channels to see the individual masks. As you can see each channel becomes a little clearer when viewed on its own.
I then create four separate images, one for each channel. I do this so that i can use layers and blending modes on each image, i pull layers across from my color map, often the cavity, occlusion or a desaturated color map, and adjust the levels.
When you're happy with how your four R, G, B, A images are looking, create a new image and copy each one into its associated channel .
Now save your _mask1 and _mask2 file, making sure to save them as 32 bit .tga. Tripple check your alpha channel isn't full black or full white, just put a dot somewhere on that channel otherwise the compiler will discard it.
Additionally make sure you save a version of your working files, i still end up spending allot of time reworking and re compiling my mask files to achieve a desired look. So chances are you will be coming back to these mask images.
This should mean that you now have all 4 of your materials saved out to the final material directory,
and we are ready to export and compile!