The Basics of Modeling and Texturing

for Rise of Nations

Part 3) Texturing

Texturing gives a 3D Model its face to the world. It is afterall its skin, and a vital part of what makes a unit. Since units are one of the things a player looks most often it in a game, not only does it gives the unit its looks and personality, it also extends a player's impression of the units to how he/she feels about the game as well. Therefore besides actually building the 3D Model, texturing is purhaps the the most important task in creating a unit. While artistry is crucial in all steps of unit making, texturing however is the step where the artists can really shine. Often the issues surrounding optimizing the 3D model for real time games forces the modeler to make compromizes in creating the model, but with smart planning and good texturing techniques you can add a lot of detailing and visual effects to compensate for any sacrifices you had to make in the modeling process.

Texturing, like the modeling process can take a lot of time, since you can keep tinkering with it without end. It is often an iterative process of trial and error to get the texture just right, especially if you add camouflage patterns into the texture. So it serves to be judicious about how much detail one puts into the texture. The trick is to put in enough but not overdo it. It also depends on the scale of the unit and how far you can zoom up close to the unit, how much detail you need to add. The minimum detail generally involves lines to distinguish edges and surface characteristics such as portholes and wheels on a tank for example which you may not have explicitly modeled in 3D.

1. First we will have to decide the colour scheme. A good place to start is to look at some photos or paintings of the object you are trying to model. Again the internet has a vaste amount of resources to use as reference. Usually the sites that has profile pictures also have accompanying color images of the thing you are trying to texture. Just from looking on google and you will probably find a lot of references. We could use a desert camo, the gray color scheme or we could use a green colour scheme. Since we are creating a German Tiger tank, it seems customary that we use a gray color scheme.
   
2. Now that we have decided on a color scheme and collected a few reference photos. We need to start Photoshop and load up the texture template we created in the unwrapping process. It is probably still in a bluish color, but since we want our tank to have base coat of gray. We need to turn that blue into grey. The easiest way is to turn down the saturation. To do this select Image->Adjust->Hue/Saturation. Bring down the saturation until you get a grey shade that you like. You can also adjust the Hue and brightness to fine tune it. After you are done, it should look something like this:
   
   
3. At this point there are probably a lot of extra lines on the template you don't need. There are two ways you can remove these extra lines. The first way is to use a combination of the magic wand, polygon lasso, and rectangular marquee tool to select all the areas you want to blend into the base background color. Pressing the Shift key while you select the regions will add the new region to a previously selected region, if you wish to select more then one area at a time to blend. This way give you more control but is a lot more work. However, a easier way is to simply select the black background areas in the texture template with the magic wand. You may need to increase the contrast in order for the magic wand tool to pick up all the areas that is needed. Then bring up the Select->Inverse tool to reverse the selection area. This will select all of the skin areas that will fit on top of the tank without regard to any edges you may want to preserve. This will require some more work later on, but I generally prefer to do it this way since much of the work will involved the fine tunning and detailing anyways.
   

   After you have selected all of the regions you wish to blend, select the Filter->Blur->Gaussian Blur. Set it to any where from level 10 to 20, then click OK. You may need to do the selecting and blurring in multiple steps since it is easy to over select and you dont't want to keep starting over, or correcting the mistakes you made. But if you did it properly the texture template should now look something like this:
   

   
   

   You will want to save the original un-modified texture template in order to help clean up the texture and help you find the edges later on. So save any modified versions under a different name as you proceed.
   

4. The texture right now is a little boring at the moment. Generally, the surfaces of objects isn't very smooth or completely uniform. So we need to add in some scratches, bumps and stains on the surface to create a more realistic skin. This is also where you would want to add in camouflage stripings as well. To begin, select the non-black areas once again. Now select the paintbrush or airbrush tool, it doesnt matter which. Then select a color that is slightly darker then the base coat. Start drawing within the selected confines of the tank skin. Just draw around randomly, but make sure you darken the areas you expect the tank to be dark. Then change the color to a lighter shade and repeat the process. Now select the Filter->Blur->Gaussian blur tool. Set it to around level 10, then click OK. This will create a more gradual transition between the different levels of shading. You can play around with different colors, brush styles and sizes, repeating the blurring process at different levels to fine tune the look of your texture.
   

   Now select the Filter->Noise->Add noise tool. Then set it to around level 5 to 10, check the monochromatic setting then click OK. Then again, select the gaussian blur tool, but this time only set it to level 1.0. This is a very good way to make your texture look realistic and more natural without too much work. The texture should look something like the picture below.
   

   
   

   As you can see, we aren't done yet! We still need to add more effects before we add in the detailing. For example, rust stains is a nice touch to tank textures to give them a more realistic feel. Select the areas where the fenders are located. Then choose a redish orange color, now use the pencil tool to draw some lines in the selected area. Use different shades of red and orange, and draw more lines. Now use the motion blur tool, set it to the proper angle (in this case its 0 degree) and distance of around 5. This will blend the stains in the direction one would expect mud and rust stains to cake onto the tank surface. We continue this refining process by adding more motion blurring where we think we need it to create a more brushed metal effect. The direction/angle of the motion blur will depend on the part of the tank you are dealing with. For example the side of the turret, you may want to angle the blur at around 90 degrees in this case.
   

   Finally certain portions of the tank should be lightened or darkened depending on where they are on the tank. Generally top surfaces should be lightened, and side and bottom surfaces darkened. Use the polygon lasso tool and rectangular marquee tool to select the regions you want to work with. Then select the Image->Adjust->Hue/Saturation tool and adjust the brightness as appropriate. The RoN game engine does have lighting effects but I find that it needs more help to really create a realistic looking unit. This is especially important with curved surfaces, in particular if you had to approximate it using more angled surfaces. You will have to create transient shading effects to compensate for this. Keep going back to the beginning of step 4, adding more effects, experiment with different colors, levels and types of noise and blur until you are satisfied with the overall effect. The Filter and Image menu contains a host of other effects and adjustments that you may want to play with. You can also use layers to create even more effects but this is a little more advanced then necessary for this example so we won't touch this in this tutorial. But just experiment with different effects until you are satisfied with your texture. When you are done, it should look something like the picture below.
   

   
   

   You should try to get the basic look of your texture done here (including any camouflage striping if you choose to include it) before proceeding to add any further detailing.
   

5. Now we are ready to add in some detailing into our texture skin. If all you have are reference photos. You can still use that as a guide for adding in details. Although the process maybe a little more labourous, and you will have to depend more on your artistic skills to a greater extent. However, if you have the pictures of the perspective views and scanned in, it will greatly help reduce your work.
   

   We begin with the detailing on the hull of the tank. Luckily we do have a set of top, side, front and back perspectives. Load up the views into photoshop along side with the texture skin you are working on. Using the rectangular marquee, select the top of the hull from the top perspective view, and copy it into the clipboard. Now bring the focus back to the window with your texture skin, paste it. It should create it as a separate layer. It will probably be the wrong size and orientation however. So what you will need to do is to reorient it and resize it to fit over the portion of your texture that corresponds to the part of the tank that you are detailing. Use the Move Tool to move the layer into its approximate location, then select Edit->Free Transform or you can rotate and scale in separate steps which ever you prefer. But make it fit snuggly in its proper place on the texture skin. Click on the Rectangular Marquee tool to lock in the transform and scaling operations. Now the layer will probably completely cover up the work you just did to colorize the texture. So what we need to do is change the layer effect on our texture. Go to the Layer panel (if you dont see it, then select Window->Show Layers) then double click on the layer containing the perspective view you just pasted in. This will bring up a Layer Options panel. Change the mode to multiply and Opacity to about 50%. This will leave just enough of the layer visible yet leave the base coat more or less as it was. Use the Eraser Tool to remove extraneous lines that you do not need on this guide layer. This is shown on the picture on the left.
   

   
   

   Continue to add details to the tank turret, wheels, tires etc, either using the perspective pictures and layering, or just draw them in if you need to (you will need to touch up all these details later anyways). I found that instead of using strictly black lines for example to emphasize edges or other details, a more realistic look can be achieved by using the Brightness tool to create shades and highlights. This is especially good for camouflage striping (or things that arent necessarily a shade of gray), the brightening and darkening makes the details more part of the body of the tank, rather then if it is was merely drawn on top of it. Use the Rectangular Marquee or Polygon lasso to select edges and lines, and/or use Select->Modify->Smooth (with a pixel setting equal to the size of the circle you want, and then Select->Modify->Border (with a pixel setting of around 2) to create a circular or a ring selection that maybe good for wheels or the commander's copula. The end result should look something like the picture on the right.
   

   When you are more or less happy with the detailing, use Layer->Flatten Image to combine all of the layers back into a single layer which is needed for a texture skin. You may want to save the PSD file before collapsing the layers in case you want to make adjustments later.
   

6. As you can see the details are pretty faded looking. This is where you can't really take the easy route, and have to really apply your artistic ability. But if you had the layers as guides at least a lot of the work will have been done for you. Regardless, what you need to do is to start touching up the texture skin both to bring out the details and to fix the base coat if it is no longer exactly what you want. I like to use the Rectangular Marquee tool to select parts for adjustments. Most likely you will either need to lighten or darken various parts, or change the hue and saturation slightly. Then use the Pensil or fill tool to do specific parts that need special attention. Again don't forget to use all of the tools we have discussed or any others you've discovered to experiment and adjust the texture skin as you see fit. Again this is where artistry comes into play. When you are done, hopefully the texture skin will resemble something like the picture below:
   
   

   However, you can also cheat a little at this stage and possibly use existing skins or reference art to just paste in parts like wheels, machine gun barrels etc and using different layer options to integrate it as you see fit.
   

7. We are almost done, and in fact the texture skin is complete if it wouldn't be for the team colors that we need to show in an RTS game. Go to the Channel Control Panel. You should see a RGB channel, Red Channel, Green Channel and a Blue Channel at the very least. If there isnt another channel listed call "Alpha 1", then click on the Create New Channel icon at the buttom of the channel control panel, just to the left of the Trashcan icon.
   

   If that channel is showing all black, you will need to change it to all white. Either use the color select and Paint Bucket Tool, or Image->Adjust->Brightness/Contrast and push it all the way up. What you need to know is that in Rise of Nations, the White on the Alpha channel will determine the part of the texture skin that will show up as is, any shades of gray will be replaced with the player color, and black will make that portion of the texture skin transparent. So for example what you can do is to make a version of the tank without the ammobox behind the tank turret, if the model was constructed with it as a separate object and has another surface behind it to cover up the hole.
   

   
   

   What we will do with our Tiger Tank however is to add some striping, iron crosses, and a zigzag tooth (it is a Tiger Tank after all) pattern to show off the player color. So we proceed to add the patterns by first selecting a grey color. Then we trace out the each of the player color patterns we want and using our Paint Bucket Tool fill it with our Alpha channel representation of the player color (which again will always be grey here). But before going to the next portion of each player color pattern, I also like to add a border around the player color sections. Select the RGB channel on the Channel control panel (without deselecting the pattern on the edit screen). Bring up the Select->Modify->Expand tool and set the Pixel width to 1 or 2, which ever you think you need. Then in the RGB channel, fill this area with black using the Paint Bucket Tool. This will help bring out the player color from the texture base coat.
   

   You can continue to touch up the texture skin, until your hearts content. But this is pretty much all you need to do to create a texture skin from scratch. The texture skin should look something like the picture below when you are finished:
   

   
   

   Now save the texture skin as a TGA file, and you are done!
   

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By One_Dead_Angel