SimGuruMorgan took to Twitter yesterday to explain that tan lines will work with all types of clothing no matter if its Custom Content or Maxis clothing.
Here is what she had to say:
Hi custom content creators! As you might have noticed, in Island Living sunbathing supports tan lines from whatever clothes your Sims are wearing. Tan lines will work with your custom content as well (so long as you set it up your alpha channels properly).
(Read on!) pic.twitter.com/oBISNKFcZL
— MerMorgan?♀️ (@SimGuruMorgan) June 11, 2019
Please note this does not work for accessories. The only accessories that do support tan lines are socks, tights, and full-helmet-hats.
— MerMorgan?♀️ (@SimGuruMorgan) June 11, 2019
The alpha channel of the diffuse texture is used as the mask for applying a tan. That means in order to get good tan lines, be sure that your alphas are properly aligned with where you want a tan applied.
— MerMorgan?♀️ (@SimGuruMorgan) June 11, 2019
On our end, the game does automatically apply a slight blur to the edges to make them feel more natural, so you don’t need to worry about doing that yourselves.
— MerMorgan?♀️ (@SimGuruMorgan) June 11, 2019
Hope that helps, and feel free to let me know if you have any questions, and I can try to get you answers.
— MerMorgan?♀️ (@SimGuruMorgan) June 11, 2019
For more information on tan lines working with Custom Content. Check out this post over at the official The Sims Forums.