i am very confused about the differences of skin types in sim 4. i tried googling "Sims 4, explain skin overlay, mask, normal" and i couldn't find answers, i tried different search terms too. Even looking at download pages for sim modders who make skins they don't seem to explain what the difference is between a Skin Mask, Skin Overlay, and just a skin. It's like everyone "magically" understands what these things mean... except me Am i a moron?

It seems like there are 4 (or 5) different types of skins for Sims 4 .. i've come across:

Skin Overlay
Skin Mask
Non-Default Replacement Skin
Default Skin
Base Skin ^ (pretty sure this one is the same as Default or Default Replacement..but.. maybe not??)

Are all of those different things? Are any of them the same? What do they mean? How do they differ? Sorry if this question has been asked before, like i said maybe i am a moron, but i literally spent an hour this morning trying to google to find an answer, and spent an hour or two last night trying to find definitive descriptions of what those skin types mean... and i'm still as confused as ever

Default skins, like base skins, are the Maxis skins all sims have. These skins are the colour (ethnicity) skins.

Non-Default Replacement are more colour skins that will not override the Maxis skin colour set. Giving more variety when choosing ethnicity tones. Default Replacement skins will override the Maxis skins and change all your pre-existing sims to the new skin colour tones.

Masks and overlays are clever ways of changing a sim's skin colour and body detail appearance. Found in the Face Mask area of Cas and not part of the general skin tone choices.

Mask and overlays are commonly the most detailed types of skins, some with very realistic body features from head-to-toe. They override nothing and you have to put them on your sims yourself. The Face Mask section was not designed by Maxis to house such things, just face wrinkles, face freckles, facial moles and such the like, but as I say, clever CC creators use that section to put their complete body overlays.

I hope no one minds that I am 'reviving' this thread, but I am a bit confused about one thing:
I see some creators have 'Default Texture replacements' is this the same as a 'Default SKIN replacement', or am I able to use both simultaneously? I have googled extensively but I cannot find a clear answer. Right now I have Kijiko's ' Skin Texture Overhaul' and their 'Skin Tone replacement' (I believe that Skin tones are independent from actual Skins?), but I am unsure if I can download a skin (like S-Club's).

If anyone could clarify this, I would greatly appreciate it!
~Piffy

I added this same question. Thank you for the clarification.

thank you for the help! this is my first time in a long time playing using mods