Create or custom an existing skin with Sims 4 Studio

This isn't something I've done for Sims 4. Tried several times for Sims Medieval but I can't paint or draw so it's been failure after failure for me. Okay, now that you know how unqualified I am to answer your question, here is what I know.

*Clone a skin detail like "Skin Detail, Mole (Right Cheek)." Choose the base game version.

*Export the diffuse. You can export as a PNG or DDS but prolly PNG is better, I think. Open it in Photoshop (Or GIMP).

*Save one of these images to your computer and open it in Photoshop. Copy and paste it to your diffuse. You should have two layers. The top is the diffuse you exported and the bottom is the template I linked above.

*Here's where I get lost as it requires painting skill of which I have none whatsoever. I've seen people use real skin from photos but you'd need one that's preferably nude (or at least topless with underwear, if that makes sense) and is well lit so there aren't weird shadows on the skin. Although there may be YouTube videos that teach how to remove shadows on skin. Then you'd need to use the warp tool or liquify or something to make the skin fit the Sims 4 template you downloaded. If you want to add highlights or shadows and you need your lines to be precise you can use the pen tool for that. You'll use blur, smudge, dodge, burn, levels, etc., etc., etc. Every project is unique.

*In the warehouse, you'll need to make sure the sort layer is correct and composition method is correct.

*You can read about the sort layer here. I don't know exactly what it does. I think it has to do with how the skin is rendered in the game and how it's layered with things like makeup. Sometimes a skin will cover up makeup and the sort layer tells the game that it's supposed to be layered under makeup. The best thing to do would be to open a skin that you have and that you know works with makeup and use that sort layer number. Click on the CAS Part in the warehouse and in the righthand window is where you find sort layer. Make your changes BEFORE adding new swatches. If you don't you'll have to edit the sort layer value in every single swatch which is tiresome. If you edit one swatch then add new swatches each new swatch will automatically have the sort layer value you entered.

*Make sure the Composition Method is set correctly. Again, not entirely sure what this does but it, too, seems to involve layering. This post may help. The advice I gave above regarding checking a skin you know works applies here, as well.

There are three tutorials here, here, and here that maaaaybe will help you. The real trick is getting the parts of the skin such as the clavicles, knees, nipples, etc. to match the EA skin, and by that I mean match the location on the EA texture, e.g. the clavicles of your custom skin needs to be placed where the EA's clavicles are located. Look for YouTube videos on how to...morph, I guess, custom skin to fit EA skin. I'm sure there are plenty. If you find a good one post it here for others to see. There are also numerous posts about skin in the creator help section. You can search the forum. You can do a Google search like "skin sims4studio.com" and it will show posts from this site. I find it easier to search via Google.