Installing CustomSkinLoader will stop 3dSkinLayers from working.
They say it has something to do with these lines.
https://github.com/tr7zw/3d-Skin-Layers/blob/main/src/main/java/dev/tr7zw/skinlayers/SkinUtil.java#L73-L109

GameVersion: 1.21.4
3DSkinLayers version: fabric-1.7.4

They then don't use a vanilla friendly way of loading the texture, so it's an issue/incompatibility on their end. I need to get the raw texture, and support the ways vanilla loads them.

dev of customskinloader

So I guess the root issue is that they switched to a self-made "FakeThreadDownloadImageData" to better support multiple mc versions, instead of using what Mojang already uses and provides. I might at some point down the line add explicit support or their workaround into a lib or maybe the mod itself, but that is a low priority now (seeing how it's a self created issue and has a workaround available).

hey thanks for answering. your point is totally understandable and i agree there is no rush at all since there is now a bridge mod, i will tell you if it ever stops working with future version as well as telling custom skin loader dev. much love <3

hey man. i love 3d skin layer i really think its one of the best quality of life and cute and best mods to have in any modpack. im also a big fan of customskinloader nad i love it and everything was fine in 1.21, i loaded my skin locally and it appearead with 3d layers, but for some reason it doesnt in 1.21.5. Please man i love this method what other choice do i have to load skin and cape trough a local file like custom skin loader lets me? why did it work some updates ago? Please.

i did but bro what could be the issue please?

they dont seem to be anwering and i absolutely love this mod i dont understand how and why it doesnt work anymore 😭😭😭

I can tell you, I didn't change anything in regard to the skin loading in over a year. So if it works or not is fully depending on customskinloader. If their loaded skins don't work, then they are not loading or applying them in a normal way that mc would, therefor it's not working.

As stated before, please ask customskinloader.

Will have to check what that thing does. Also weird that they made a mod instead of just pr-ing the fix to either 3d skin layers or custom skin loader 🤔

yeah thanks for the answer. in the issues from custom skin loader they linked this new compatibility mod. https://www.curseforge.com/minecraft/mc-mods/skinlayers3d-customskinloader-bridge

im just a big worries bout the future of this mod, will i have to wait for it to get updated to have both of the mods working? also whatever this mod is doing do you think it could be implemented? thanks

Added a note to the future modpage.