Advanced Skinning/Upscaling Techniques in Photoshop

[tjsase 114]

Greetings, fellow modders! As I sit at my computer editing various textures in Photoshop, I often discover some interesting techniques for upscaling the KotOR games' low resolution/compressed images, and I hope to share some of my experience here. Some of these techniques might also be accomplished using GIMP or any other image-editing software. Optionally, you may wish to extract the relevant model into a 3D package to preview your various changes. We will begin on T3-M4 to demonstrate the two most useful techniques: edge-redrawing and edge-smearing.
 
Extraction/Setup

First, be sure to extract the desired texture to a location of your choosing (I usually have individual folders for the various mods I work on), then open it in your image editing program.
 

 
Save the file now as a PSD. Every few minutes, be sure to save in case of computer failure (believe me, as someone who uses CS2, you'll wish you had saved just a few minutes before it crashed).
 
Now you can upscale the image to whatever resolution you desire, SO LONG AS it is square and an exponent of two, as in 2^x, due to the way video cards work. Acceptable resolutions include 32x32, 64x64, 128x128, 256x256, 512x512, 1024x1024, 2048x2048, 4096x4096, 8192x8192 (if your computer can handle that), and so forth.
 
If you need to edit the image in an odd resolution, you can always stretch it to one of these resolutions later. If you image appears distorted by this, fear not, as the game's engine will stretch it back.
 
I recommend resizing images using bilinear filtering. Nearest neighbor will create a blocky look, while bicubic will add subtle halos around each hard edge within the picture (if you are happy with these effects, by all means, go for them!).
 
If you wish to preview the texture in a 3D package, it's helpful to light the scene as if it were in-game. Usually this is accomplished with a few overhead lights and some slight ambiance in the material properties. Hopefully your package allows PSD files to be assigned as textures. If it does, you will be able to manually reload the texture after each time you save a change. This is useful for fixing seams and odd UV mappings.
 

 
Another helpful tool is the UV Snapshot. Your 3D package may allow you to save an image of the UV map of the model, which you can then composite onto the texture to guide your work. Be sure to save this image to the same resolution you are currently working in.
 

 
Just be sure to align the wireframe, as it can often be off by just a few pixels. Using the 3D model, you can easily see if adjustment is necessary and can nudge the wireframe guide.
 

Edge-Drawing
 

Now for some restoration. We'll start at the top of this little droid's head... or whatever you call that thing on its... head. What we want to do is to enhance that blurry, black ring around the perimeter. Do do that, we need to either redraw or smear the edges. Let's start by redrawing. Of course, repainting the whole texture is long, tedious, and messy. But there are a few tricks to do this semi-automatically.
First, let's select the brighter portion of his head:
 

 
Now, create a new layer, and fill this selection with either black or white depending on which most closely matches the selected section. Since this shape is bright and surrounded with dark edges, let's fill it with white.
 

 
Now create a new layer under this one and fill it with the opposite color, in this case, black.
 

 
You may now merge these two layers. We have created a shape with a hard, defined edge that matches the shape selected. However, if we composite this now, the entire image's color will be heavily altered. Instead, we must ensure only the edges are composited. To do this, we need a high-pass filter, found in the "Other" section under the filters menu of Photoshop. Use the high-pass filter on our freshly drawn layer, and set the radius to half of the times the image was enlarged (for example, if the resolution is now four time as many pixels in both dimensions, set the filter radius to 2.0 pixels).
 

 
Now, set the blending mode of this layer to "Soft Light" (occasionally "Overlay" works, though it's harsher on the colors), set the opacity to your liking, and presto! This edge is looking pretty decent right now.
 


 
Looks much better than before, eh? Of course, I'm not satisfied yet, as the aliasing of the original texture is still apparent. In cases like these, I use the edge-smearing method. When you smear the edges, you're not so much re-drawing the edge so much as you're refining it. The basic technique involves selecting a shape and smearing the edges of the texture towards the edges of the sharp selection.

 
Edge-Smearing

Let's return to the just-upscaled texture. Since we are editing a component of the texture itself, we should copy that section into a new layer for safety. Select the area around the edge you plan to enhance and copy and paste it into its own layer (I got lazy here and just copied the whole square).
 

 
Next, select the inner shape within the edge you plan to edit. If the edge doesn't close, then simply extend the selection past the edges of the model's polygons and a good distance away from the edge.
 

 
Time for some finger-painting! Go to the smudge tool and set the strength to about 50%. Use a soft-edged brush and set the size of the brush to affect as much of the edge as you can per smear without extending into the texture's details close to the edge. What we want to do now is smear the soft texture edge outward and slightly past the selection edge, enough that the blurred portion has disappeared. Use short strokes and go along the edge until you've finished.
 

 
Now invert the selection and do the same procedure from the other side of the edge, dragging the blurry edge towards and slightly past the selection edge.
 
 

 
Pretty good, no? Of course, this method isn't perfect either. At times you may inadvertently smudge some important details that are too close to the edge. When restoring a texture, you should use both edge-redrawing and edge-smearing on a case-by-case basis. Edge-smearing is great for edges bordered by low details and flat colors, while edge-redrawing is better suited for tighter edges or edges bordered by many little details that provide enough noise to mask the aliasing of the original edge.

 
Part II has been posted.