Introduction

This is a relatively detailed reference tutorial. It's mostly aimed at making things easier for the modder who is tired of looking at retexes where everything is the same shade, including metal parts that shouldn't be. Hopefully, this will allow you to use GIMP and NifSkope to make better retextures with more color variety, higher contrast, and unique additional images. You may not need all the parts of the tutorial at once, but I hope this will serve as a useful resource. I've also covered normal and glow maps, since I haven't seen many resources for those.

Here is a link to another tutorial with more information on transparency than this one has:

GIMP

Important Preliminaries: The Modding Toolbox

1. You'll need a BSA unpacker in order to get at the default game meshes and textures. Get one here: TES4BSA
2. You'll need the GIMP, a powerful image editing program. You can use Photoshop, but GIMP is free and I will be discussing commands and features of that particular program. Get GIMP and the GTK runtime environment (you need it to run GIMP) here: The GIMP
3. You'll need a .dds plugin for GIMP to be able to open the game's texture format. Get it here: .dds plugin for GIMP
4. You'll need a normal map plugin for GIMP to be able to generate normal maps. Get it here: Normal Map Plugin

5. You'll need NifSkope in order to retexture game meshes. Get it here: NifSkope

Choosing the Mesh to Retexture

It's completely up to you. I'm going to use the Leyawiin cuirass for an example, because many mods involve new guard cuirasses. In this case, I open the folder with all my unpacked BSAs in it and open the folder called "meshes," then "armor," then something like "leguardcuirass." Then I should see two folders that say "m" and "f." Since I'm female, I'll start with the cuirass under 'f', but since the same texture goes on both it doesn't really matter. Double-clicking the mesh opens it in NifSkope.

You might see the mesh looking all white, even though the "nisourcetexture" node in NifSkope has a texture there. This is because the texture is in a different folder than NifSkope expects. Rename it to the correct one (BSAS/textures/armor/leyawiincuirass.dds or whatever) and the texture should appear:




Leave that window up on the screen, but don't save yet.

Opening the Texture with GIMP

Now click through the bsas folder until you find textures/armor/ and the leyawiin cuirass. If you set all your filetypes to open with GIMP when you installed the program, just click on it. Otherwise, if you click on it directly you'll get an error message. Right click and choose the option that says "open with" and "gimp-win-remote" to open the file with the GIMP.



Now we're looking at the texture in that lovely blue-gray interface so beloved of open source folks. You might get an error message complaining that the image is a volume map, but just click "OK" and ignore it.

The texture looks nothing like the mesh. There's a good reason for this, and it has to do with UV maps, which are a longer subject for another tutorial. Different parts of this texture are being placed on different parts of the mesh, and there's no connection between where they are in the texture and where they will be on the final project. Some bits of the flat texture will even be reused on more than one part of the mesh. That's why it's good to look at our project in NifSkope as we go, so we can see what we're doing.

Saving A New Texture and Mesh

Use File-Save As to make a copy of the texture with a new name, say MyCuirass.dds in the folder data\textures\armor\YourName. Be sure and type the extension or GIMP won't save it. I usually save with no compression and don't generate mipmaps, and that's always worked fine, but you may have your own preferences in this area. With a very shiny or transparent texture compression can be a good thing.

For more info on the .dds file format and what mipmaps mean, here is a useful section on the Construction Set Wiki: DDS Files

Now go back to your NifSkope window and change the texture path there to where your texture is, instead of the game one. When that's done, save the mesh as something new too, such as data\textures\armor\YourName\mycuirass.nif.

This is important, because if you mess up the original unpacked .nif and .dds it's hard to get them back without unpacking all the .bsas again.

Removing an Emblem: Rectangular Select, Cut, and Paste

Now back to our texture. I chose this one for a good reason - most of its parts are rectangular, so we can easily select them. Right now I'm going to use the rectangular select tool (press r, click and drag) to select the horse emblem on the cuirass front.




We're going to be using rectangular select quite a lot.

Now I use edit-cut to make the selection disappear. There's a hole in the texture now, with a grid showing behind it. That's no problem, because we'll fill it back in. Use the rectangular select again to choose a longer, narrower area on the left side of the hole, then alt-edit-c and alt-edit-p to copy and paste it. Now you can press m to move this selection over to cover up part of the hole. When it's where you want it, go to Layer-Anchor Layer to anchor it in place. Repeat with the right side, and if necessary top and bottom, to fill in the hole completely.




If you want to make this area look more continuous, take a look at the "wrinkles" painted on either side of the new blank space. If you copy them, then drag them down and diagonally, you can make it appear that they continue right down into the selection. This helps to make it 'fit in' and not scream 'Something else was here!' You can also use the smudge command (s key) to blend the edges, but do it sparingly or you'll have a very blurry texture. Remember, any tool you use can be resized in the main gray GIMP area. Click on the little round circle or the little black square, depending what tool you're using, and a drop-down menu will appear with all the possible brushes. There are also different sites where you can download new brushes for GIMP; a Google search will turn up many of them.




When this part looks satisfactory to you, save the .dds. Now go back to NifSkope and look at it. Your new cuirass now has no horse on the front. If you want to, you can easily cut and paste an emblem of your own design onto the cuirass, and you won't have to worry about it being the same shape as the one you cut off.

Isolating Parts of a Texture: Paste as New and Colorize

In order to make different parts of our texture look different, we could just use the rectangular select and color tools, but this method will give us a little more control.

There's a long, narrow piece running down the center of the Leyawiin cuirass. Rectangular select it and copy it. It might take a couple of tries to get that shape and that shape only. Feel free to zoom in and out using the "view - zoom" menus. “View – shrink wrap” can also be useful to avoid wasted space on your monitor.

Now go to Edit - paste as new. The rectangular piece is now in its own file that we can edit. On this new file, go to tools-color tools-colorize. Now you have three sliders, and the rectangle seems to have gone black. The sliders in front of you say something like color, saturation, and lightness. "Color" tells you what color the selection will turn, "saturation" is how intense the color is, and "lightness" is just what it sounds like. Play with the sliders until you get a color that interests you.




Other color tools will allow us to make a selection more than one color or change it in more than one way, but we'll do the simplest way first. If you want to make your color even more vivid, or perhaps a little subtler, you can also use tools-color tools-brightness and contrast. This one also has only two sliders and is very easy to use.

Once the new selection is a new color - I'll make mine red - go to select-select all and then edit-copy.

Now go back to your original texture and click edit-paste. The rectangle is back in your texture. Drag it back over to where you copied it from and paste it over the original bland one. Now anchor it and save the file. Remember, you can always press CTRL+z if something goes wrong.






Look at NifSkope again. That insignificant little strip actually covers several different parts of the cuirass, giving us a nice red lining peeking out here and there. This is why we need NifSkope when any retex program would do - we can see exactly what our changes actually do on the mesh itself.

Note: Parts of the Texture and What to Do With Them

You now have two files open, mycuirass.dds and the unnamed file with the pasted red rectangle in it. If you don't think you'll want it again, you can just exit the pasted one without saving it, and it will disappear forever. If you think you might need to make several different retexes of this cuirass in future, it's not a bad idea to save it separately. I sometimes do this when I know I'll be making several versions of something for a project.

Now let's look at our main texture again. Notice how it's almost all divided into neat squares and rectangles? All textures won’t be this neat, but in this case you can recolor any of these parts separately from the others. You can recolor just the cuirass fabric, and then paste a new emblem onto it. You can give it black metal parts or a shiny belt. This is the answer to all those bad retexes with bizarrely-colored metal on them - cut the metal parts off and tweak them separately.

For those parts that aren't strictly rectangular, here's another method.

Isolating Parts of a Texture: Erase, Color Select, and Fuzzy Select With Layers

If you need to copy a texture part that isn't quite rectangular, go ahead and select it in a large enough rectangle to contain all of it. This will mean it includes part of the rest of the texture, but that's all right, we'll fix it. Copy and paste as new again. Now press shift-e to bring up the eraser brush. Make sure it's a size you can use comfortably for the small section you need to erase. Now use it to erase the part of the texture you don't want. You can erase in a straight line by pressing down the left mouse button, then holding down shift and dragging the mouse. A line should trail out behind it. Click again when you're ready to create the line of erasure.





You can also use this with parts of a texture that aren't remotely rectangular at all. It takes longer, but it's sometimes worth it to get exactly the color effect you want.

If you want to select parts of a mesh that are mostly one color, like the yellow-gold parts of the archmage's robe, you can also use select-select by color and click on that color. Then click select-invert to select everything BUT that color, then edit-cut. Now everything but the yellow you selected is gone. This is also tricky, because any given texture contains many subtle color shades that may seem similar to you but very different to GIMP. In this case, remember that you can select more than one color by holding down shift and clicking away with the color selector.

Fuzzy Selection

You can use the tools-selection tools-fuzzy select to copy and remove parts of a texture that are oddly shaped, but this takes a little practice. (You can also bring it up just by pressing the U key). Remember that if you're using fuzzy select, you can hold down the shift key and keep clicking and dragging to select a bigger area. If you look at the main GIMP window behind your open file, you will also see a slider that you can use to make the selector more or less sensitive in what it picks up.

You can also use fuzzy select in another way in order to create very precise selections with absolutely ANY kind of outline. Here I'll use the example of the lips on the Bethesda facial texture, because I do a lot of race texturing. We'll try giving the plain old Bethesda face red lipstick. That will give it to both sexes, since there aren't separate facial textures for men and women, but never mind, we're not using it in a mod at the moment.

I first open the textures\characters\imperial\humanhead.dds file. This has me looking at a very compressed version of a human face. Save it as something like textures\characters\MyRace\myface.dds. Bring up the NifSkope window with meshes\characters\imperial\humanhead.nif. It already has the default texture assigned to it. Change the texture path to the path of your texture. You now have something that looks like the original Imperial face on the mesh.

Back to our new face in GIMP. Go to dialogues-layers and a little square will pop up showing the layers of your image. Right now there's probably only one. (If there are several, do image-flatten image to get rid of the mipmaps.) Click the button in the dialogue that looks like a piece of paper to create a new layer, and choose "transparency" when that option comes up. This layers dialogue will be very useful to us as time goes on.

Make sure and click on your new empty layer in the dialogue to make it the selected one. The selected layer has a dark bar over it. This is very important, because otherwise it's possible to have two layers visible at once and no idea which one you're working on.

Make sure your new layer is above the other one. There are two little arrows at the bottom of the layers dialogue that let you move a selected layer up or down. Each layer also has a little eye symbol next to it that appears or disappears when you click on it. This tells you whether or not the layer is visible. Make sure both layers are visible, but the NEW one is selected.

The picture doesn't look any different. This is good. It shouldn't yet. Look at the outline of the lips. They are not square, round, or any other shape that would easily lend itself to selection tools. Choose a paintbrush size and set the paint color to black. Now paint over the lips. We're painting in the new layer, remember, so you're not defacing the original texture. Make sure the whole outline of the lips is covered. This may take a couple of tries, because they're such an odd shape.

If it helps, the layers dialogue also lets you change the opacity of a layer. This means you can temporarily make your painted layer translucent in order to see that the edges are in the right place. Make sure you set the opacity back to 100% when you are finished.

Once you have your flat black lips, look at the layers dialogue again. Now make the main layer with the face in it invisible, so that only the new layer can be seen. It should have a blank grid in the background with a solid black lips shape on it. If it doesn't, you may have painted on the wrong layer.

Go to tools-selection tools-fuzzy select. Click on your lip shape until the whole thing is selected. (You can also use select by color for this.) There should be a moving dotted line around it. Click Select-invert. Now go back to the Layers dialogue. Make the lip layer invisible and the original face visible. Look at the texture again. The black shape is gone, but you now have a perfect dotted line outlining your lip section. Click Tools-Color Tools-Colorize. You should now be able to make this lip shape as vividly red as you please.

When the lips are the color you want, do select-none, then go back to the layers dialogue and delete the black shape layer. The delete symbol on the layers dialogue is on the far right and looks something like a mushroom, for reasons fathomable only to those who created it.

Save your new file. Look at it in NifSkope. You now have Imperials with lipstick.

If you think about it, you can discover many other uses for this sort of tool. Working with the layers takes a little practice, but it works much better than the select-copy-erase method I originally recommended when you're working with oddly-shaped areas.

More Advanced Color Tools: Hue/Saturation/Value and Color Curves

Hue/Saturation/Value

I use this sparingly, because often you can get results just as well with color select and brightness/contrast, but there are times when it's quite a powerful tool. You can use this to make changes to the entire picture, or use color select to make changes to just one color.

Let's start with the whole picture. Suppose we're looking at the Leyawiin cuirass again, and we'd like the parts we made bright red to be blue instead. Click on Tools-color tools-hue/saturation.




Now you're looking at a puzzling wheel of colors and three sliders under it. The wheel lets you choose a color to edit in the picture, based on what color value GIMP thinks each pixel has. Right now the wheel is set to "master," which means changes you make apply to ALL the colors in the picture. If we want to affect just red - the color I made the details earlier - click on the red color box, and the circle under it will be filled in.

There's a tiny checkbox in one corner of the dialogue that says "live preview." Make sure it is checked, so you can see what effect your changes will have before you make them "real."

With red selected, try dragging the sliders back and forth. "Value" makes the color lighter or darker, while "Saturation" makes it more or less intense. Turning the saturation to 0 will make all the red look gray, because it won't have any color any more, but it will still have a light/dark value. "Hue" is mostly what we want right now. Drag the slider until the red in the box looks nice and blue. If you have the preview checked, you can see the results on your texture.




You can also see why we have to use this tool carefully. Every single red pixel in the picture is affected, not just one shade. This can result in strange spots or effects that we don't want. Sometimes you can avoid this by using color select to select a specific shade and then using HSV on just that shade.

This also gives us another possible way to change around the entire picture's color scheme. You can click back to master and desaturate the entire picture down to 0, then use the selection tools (as in the above sections of the tutorial) to recolor it one section at a time. This isn't always necessary, but it can help when you've got an overly complex color scheme that doesn't easily lend itself to tweaking with sliders. I’ve used it to make, say, gold-colored Argonian body textures.

Remember, if you want to change everything BUT a particular color, you can click edit-select by color, choose that one color, and then click select-invert. Then do whatever you like. Play around with these things and you may be amazed what you can do.

Color Curves

This is a little more difficult.

I've pointed out one of the shortcomings of HSV, which is that it tends to recolor every shade of a given color. Color Curves lets us change shade by shade, but it's a subtle tool and it takes practice to make it work well.

To work on the entire picture, go to Tools-color tools-curves.




An exponential graph came up. Click on the little box that says "value" and you'll see you have several choices, including the colors and alpha. Just for an example, click on Red.

The curve looks the same. Now click on it. Small points appear. You can drag one particular point up and down to alter one particular shade of red, although the fewer points you have, the more shades are affected. When you drag upward or downward, the color becomes more or less intense, and dragging sideways (which is only slightly possible) tends to alter the shade. Try it and see what happens to your picture. Make sure you have "preview" enabled again.




With a light touch, this allows you to tweak around all the colors in your texture separately. The "value" graph affects how light or dark the colors are, and different parts of it deal with different hues. Dragging the "alpha" may not appear to make much of a change in your picture, but it will make it more or less shiny when you're looking at it in game, so be careful with this.

Again, this is one I use sparingly, but it can provide some complex and subtle effects if you know how to use it.

It also has another benefit: you can save each individual curve. This is useful if you're making the same changes to several different textures, say retexturing a whole suit of armor. Click on "save" and give your curve a useful name, like "leyawiinretexalpha," so that you can tell later where it belongs. Now if you click on "open" from this curves dialogue, it will bring up your saved curves and let you apply them directly to your texture. This can save a lot of time. Just remember that if you have separate curves for red, green, blue, AND value AND alpha, you have to save five curves. It won't save the entire curves dialogue for you.

Conclusion

Retexturing for Oblivion will usually involve things much more sophisticated than recoloring a guard cuirass and adding a new logo. We’ll get to some of those things in more advanced tutorials as we go along. In the meantime, you can now have any item in Oblivion in any color you want it to be. Make sure you add a normal map using this tutorial:

The GIMP

Or this shorter one:

Normal and Glow Mapping