Hi. This question is not dumb. In fact, this topic is very important and, in my opinion, never properly covered in start-to-finish tutorials.
So, there are many things you need to keep in mind when cloning an outfit:
1). If you intend on sharing your package with other people, clone Base game items only.
2). If you're making a top, start the package from a top, a full-body outfit from a full-body outfit, etc. CAS items are tuned differently to properly interact with each other and just changing an outfit type in Categories tab may not be enough.
3). Many CAS items are made of more that one mesh (s4studio_mesh_). This, again, ensures they properly interact with each other. For example, in CAS some high boots go "under" long pants, other "above". This happens because both are cut and separated into meshes in the same places and tuned to hide them in certain ways when interacting with each other. Example:
My point is, the blend you're importing should have a corresponding mesh for every mesh of the original one. What is being replaced with what is determined by cut numbers.
Please read
this to understand it better.
4). In most cases, items are split in ways that make sense. However, sometimes you may come across something that has, like, 12 meshes most of which are just random parts of the body separated into a new mesh. You can Shift-select and combine them into one with Ctrl J to use as a source object when transferring UVs or weights but do not start your package from them, find something else.
5). You don't have to use the same mesh you've started a package from as a source object for weight or/and uv_1 map transfer. That being said, you have to ensure that the mesh you're using instead has the same weight (vertex) groups. Recently people have been encountering a problem of ingame mesh distortion ( like in the linked thread ) which is caused by the fact that the original mesh does not have certain vertex groups that the new mesh has. These can be skirt ( for dresses and skirts), foot ( for long pants that cover feet a bit ), toe ( for full-body type of outfits that have shoes ), and any type of facial bones vertex groups.
6). Never transfer anything from nude/pants-like outfit to dress/skirt-like outfit and vice versa. You need something that matches yours the closest in shape. You can use dresses that are a bit longer than yours for uv_1 transfer but never ( significantly ) shorter.
7). When making dress/skirt like outfits, make sure to paint the skirt part with a different vertex color for it to deform smoother and to not be affected by some sliders. For this you will need to find a EA mesh with the skirt-like bottom and sample the color from it. Explained
here 8). If your top covers the bottom part of the body, use a full-body outfit to transfer both UVs and weights.
9). Best to not use items that have, uumm, sculpted details ( you know, bows, strings, folds, belts, etc ) to transfer a uv_1 map.
10). There was a glitch that made sims react to someone wearing an item started from a nude body part as if they were naked. I don't know if it is fixed by now, but it's best to not clone them.
11). There is also this thing called
slot rays that determines the position of sim's arms. So if you were to make a gown with a very puffy bottom, you'd need to either clone something that has the same shape or edit these slot rays.
