Some folk have been watching my Neolite attempts - I thought I'd share a trick:
Professionals can spend a lot of labour getting worn-effects on "metal" panels - this usually means airbrushing the centers or somesuch, and applying grungy textures to the edges.
That's more work than I am prepared to do for this game, where most of the ships will be seen only from wayy off, or moving quickly while attacking you.
There's a short-cut. But first - the preliminary ... you all know to do this right?
1. Get a UV map with edges.
When the model is complete - actually delete edges ... leave the minimum needed for the model to hold it's shape. Don't remove any vertices.
Do the mapping as usual - this will give you a png file with the main panel edges showing. Make sure you create a backup!
2. Create an edge layer. Open the original in GIMP (or whatever - menu stuff below will be GIMP-specific, I've never used Photoshop.) GIMP will call it "Background". Duplicate it - rename the dupe "edges" then make all the white bit transparent from the layers menu.
Keep this layer an top.
This also keeps a backup handy as the "background". Keep this at the bottom, it's there is case you make a mistake.
3. Create
another layer below the edge one - this is for your basic colors. Use the bucket fill tool to block in the colors.
I have a preference to put a textured layer below this one, and set the mode to grain merge. Other people like multiply or overlay ... play with the modes and layer order to suit.
All the neolite textures use a solid color layer above a light-metal texture (the one from the source in fact) above a dark metal texture (also from the source).
I'll call them color, lmetal and dmetal.
The color layer is grain-merged. The other two are normal.
Lmetal is chopped up to allow dmetal bits through where needed - I use it for engines for eg. (The UV map has been rigged so different color sections are positioned separately. As well as the scaling/sampling issue mentioned, it makes colouring within the lines trivial.)
4. Use the layers!
Make a habit of doing each new thing in a different layer - yes, it's a pain keeping them straight, so also name them things you'll recognize.
5. Use the edges layer to highlight the edges ...
This can be done by gauss-blurring the layer... for a typical 512x512 skin a blur to 7-8px is usually plenty. Duplicate the layer to make the effect more pronounced, or set the mode and use transparency.
To have light edges, invert the color. Use the colorize tools and play with the modes for interesting effects.
The neolite ships just keep this layer black, mode=grain-merge and opacity is normally 75% ... but darker areas often need a double layer and hi-res areas need less.
6. Use the edges layer to alter the interior color.
Sayyy what?!
Each major flat in the neolite textures starts dark in the middle, grades to lighter towards the edges, then you get the dark "burn" lines.
6a. duplicate the color layer - set the mode to "normal".
6b. add a new layer below - pick out a color from the metal layer, I used #858585 and bucket-fill the entire layer.
6c merge these two layers - call the result "aging".
This will look pretty ugly and it gets worse before it gets better.
6d duplicate the edges layer - invert the color (so it's white) and move it dawn till its above the aging layer.
6e gauss-blur to 5px - duplicate
6f gauss-blur the dupe to 10px - duplicate
6g repeat, to 20px
I usually have to duplicate that last one since it will be pretty faint and you'll want the spread to show up.
The smaller panel areas will now be completely white, but you'll still see some darker color in the middle of the bigger panels. Get the idea?
Merge all these (step 6) layers down to the "aging" layer.
6h make the white areas transparent!
Bingo!
Adjust the mode and opacity of the aging and color layers to taste.
If you remove the paint layer completely, then you get the effect of having paint worn off the edges ... gradually increase opacity of the color layer to get the right amount of wear. I've usually had good results with 75% color and 50% aging both grain-merged against that lmetal layer.
The effect can be quite subtle - I think it is well illustrated by this:
I've seen tutorials which involve hours of work for this effect - OK, a superior version of this effect on ultra-hi-res textures... hopefully this saves some labour.