Hi just decided to put a crop top on and was climbing up a wall as I noticed a weird design choice and I don’t understand it, just put a bra on as default under crop tops like the one already in the...
It's actually intentional. It gets a bit complicated, but I'll try my best to keep it short 🙂
What you're seeing is basically a cap/cover. Clothing models are finished like this to avoid issues like clipping or something called "backface culling".
To prevent clipping, parts of the character's body underneath the clothing are removed or cut.
If they kept the full character body and layered something like the bra underneath instead, they would overlap and clip very similar to how some pants clip with shoes. Our bodies are essentially invisible underneath the clothing.
The cap/cover relates to "backface culling", it's an optimization thing. For example, the game only renders the outside surface, which results in the inside surface of the model to be see-through. The cap covers the see-through geometry.
Here's an example of what happens without it.
It's becomes more of an eyesore depending on how you customize your body shape. The models can only deform so much. Often times, the body morph threshold exceeds the clothing morph threshold.