The TS4 skintone system has a lot of potential, and I've been working on a tool to make it easier to work with. TS4 Skininator is here for testing - it probably still has a lot of bugs.

Definition of Terms: (These are the terms I'm using - they're not 'official'.)

• TONE : A game file which defines a skintone. It links to the color images, the overlays, and contains various settings.
• Skintone : The skin you click on in CAS, which is defined by a TONE file.
• Skin details : A texture with shading, contouring, and details such as nipples and belly buttons. (Yes, I know there's a separate 'skin details' in CAS. Couldn't think of a better term.) There are separate textures for each age/gender/bodytype.
• Skin color image : A texture which applies color and some shading composited with the skin details. There is one skin color texture which is applied to all age/genders.
• Overlay : A texture which is layered on top of the skin details and skin color. The ages and genders it applies to can be specified.

Overview:

Create/Edit Custom Skin Colors

• Cloning Tool : Clones game skintones and creates a package with the TONE files.
• Clone Package Editor : Open and modify cloned packages.
  • TONE Manager : Add/Delete TONEs, modify flags defining the type and usage, modify the swatch color and various other settings, import and export the skin color images.
  • Overlay Manager : Add/Delete overlays, define which ages/genders each overlay applies to, import and export overlay images.
  • Previewer : Preview skintones.

Create/Edit Default Replacement Skin Details

• Make New Default Replacement Package : Select which skin details you want to replace and clone them to a new package.
• Edit/Test Default Replacement Package : Import/Export textures and preview the skin details.

Notes:

• If it seems like there's a million skin details textures, that's because THERE ARE. There's a separate texture for every age and every body type. For some purposes you're better off using an overlay. As far as I know there can be only one set of skin detail textures, no non-defaults.
• Speaking of overlays, only one will be used for each age/gender.
• The preview should be considered only a rough guide as far as color - I was unable to exactly duplicate the way the game composites the skin. The darker skin colors in particular look grayer than in-game.
• There are two skin color textures; one (a DDS image) is used in CAS and the other (an RLE2 image) in the game. For the CAS image you can import either an uncompressed DDS or a DXT5 DDS. For the game image you must import a DXT5 DDS. You can use the same DDS if you wish. However, you can add a logo or identifier to the CAS image which will show up on the sim in CAS but not in the game. That might be useful since there's no way to customize the swatch except for its color.

Moar notes:

• Randomization: Skins are chosen randomly based on the archetypes defined in their flags. The more archetypes a skin has, the more often it gets chosen. If it has no archetypes it will get chosen randomly only if there are no other skins that do have archetypes. The game skins for humans all have archetypes; the game skins for aliens don't have any.
• The 'Occult' flag determines if a skin shows up for humans, aliens, or both. Future occult types will probably have their own skins too.

I've also attached a set of templates showing how the body is mapped to the textures.

Future plans: Support for PNG import/export. I'll probably include default replacement of eye and teeth textures. I may include face skin details at some point, but there are about a billion of them in the form of overlays for the parts of the face for different face templates.

With thanks to Peter and Inge Jones, Kuree, and everyone else who's contributed to s4pi and s4pe, and to Snaitf for figuring out how to make non-default skintones.

As usual, extract the attached zip, open the folder, and run TS4Skininator.exe. Please test and report any problems/suggestions/comments here!

Edit: This tool is now available in the Downloads section: http://www.modthesims.info/download.php?t=568474