Here are the basics (females are much more interesting):
I know no other programs but for PhotoShop and Paint dot net. If you're into skin tone, as I am, you'll want Paint dot net, it's free. Get version 3.5 or higher.
My PhotoShop is CS3, but any above PS7 will do it.
You'll need TxdEditor, it's free.
I learned both the photo programs without any instruction, just from fooling around. And that's what you might have to do.
Alpha channels: When the mesh for a models comes up in txdeditor save it to your desktop or where ever as a BMP. If you want to alpha-out (make all or part invisible) a piece of clothing or whatever you'll have to save it as a PNG. Before you save it go to the upper right where it says, PROPERTIES and uncheck compressed and check alpha, save text.
PS: Using circles, rectangles or magic wand mark what you want to erase. If you want to remove all put your eraser at 100%. To make transparent use 15-30% hardness, much of this depends on the density of the color, white is easier than black. If after erasing you don't see a B&W checkered background it didn't work. Make sure it's been saved as PNG UNCOMPRESSED.
Now go to txdworkshop and import the image from PhotoShop to your destination folder. Let it load then SAVE TEXT. Now click below where it says, IMAGE/ALPHA. If you see black it's completely trans parent. Shades of gray show you degree of partial masking. Go back to IMAGE and go up top and recheck compressed. If you don't compress it it will have a lot of pixels and might cause your game to run a bit slower. God I've made that mistake soooo many times.
If you know my work you'll see most of my models have become gang members (DATA/PEDGROUP), This makes them easy to find. They'll all walk like gangsters and carry weapons. Since I don't often do males I go to DATA/PEDS and have them walk as women. While you are there you might want to change their voice.
Now launch your game, the FAM gang members will be either at the beach or in Ganton or thereabouts. Recruit one and using the camera check them out closely. I'm not interested in guns and knives so I mask them all. It's easy, they are all 64X64. You only need to mask one and use that as a template for the rest. Same procedure though, uncheck compressed export, erase, import, recheck compressed, save.
Some facts to remember: After masking clothing don't expect tits and ass to jump out onto the screen. Sometimes there is no body under the clothing. You need to check your meshes to be sure there is a body in there. Even if there is it's no guarantee it'll work. Often times the rigger or model's producer will eliminate what isn't seen to save pixel count. All that info is in the .dff. I know nothing of modding a .dff.
Now for paint dot net:
Great for skin tone and transparencies.
Skin: In the EFFECTS tab chose photo tab, chose either GLOW of SOFTEN PORTRAIT. Play with the controls. Hair color is easily done with ADJUSTMENTS/CURVES RMB. Play with it.
Change eyes PS: Download my texture collection, on here in the tool section, chose an eye you like, size it copy it and paste it over the original eye mesh you just saved to your desktop or where ever. 100 pixels is a good start. If it's too big or too small go back to your PS eye image and keep resizing until it fits. Save as BMP or PNG, whatever the original format was.
Add tattoos or adornments: Go online and search: Tattoos, flowers, oriental designs etc., include PNG in your search. If it's not a PNG image the background won't be transparent. Size it till it's right and paste it where you want. Save as whatever format the original was. Load it into TxdWorkshop, save image.
Nipples: There are nips in the texture collection as well, or you can make them from scratch. It took me 3 years to make a good nipple so I won't get into it here and now.
I run just about all clothing meshes through P.Net, in the same photo section. You won't need a glow so slide the slider all the way to the left. Play with the contrast and warmth until you get something not so flat as the original clothing meshes often are
Permissions: The rigger of a skin always gets credit of ownership. Very few guys/gals make them from scratch. Black Stallion, Camcia, Cyrex are a few. If anyone deserves having to be asked permission it's one of them. How to cover your ass is to respect a rigger's work, offer a link to their website in the readme or something like that. I've only had one complaint after uploading about 2000 models and it was just over one single mesh. People call me a thief ... the rigger is the thief. Did he ask Team Ninja Developer(s) or Tecmo Publisher(s) permission before converting a model from DoA? I doubt there are 100 people in Japan who speak anything but Japanese.
Happy modding. Mo.