Hi. The tutorial you watched was very unfortunate, pretty much everything needs to be re-done. I'll go through mistakes in the order they were made:
- like you said, the mesh is unnecessary high poly. Those folds are meant to be preserved through texture, not mesh. Judging by names, you seem to already be familiar with a concept of Highpoly and Lowpoly, but it isnt applied right. Go back to MD, select and subdivide the avatar. Lower Particle distance on the garment and simulate. Export this mesh as thin and weld, name it Highpoly. Then select all patterns again and increase Particle distance, this time
without simulation. Export this mesh as Lowpoly. Later, once you
adapt Lowpoly and make sure it works in ts4 properly, you can bake all textures from Highpoly to Lowpoly. As a beginner, you can skip this step, but it is very important for making good looking textures;
- for a garment to not clip into the body underneath, it must receive all data from... the body underneath, meaning your reference must contain all areas of the body covered by the garment. The one you used was shorter, so the bottom didnt receive the right data. Make sure to choose the reference of the same overall shape, specifically of the same length. It is also best to choose a reference with as little sculpted details ( collars, sleeves, belts, bows) as possible to avoid torn uv_1 ( look at yours in the chest area, see how they are torn where the collar was on the reference?). So you find a suitable maxis item, export the blend, open, join all s4studio_mesh_ into one if needed, rename the mesh to Reference, then
import your obj into this scene;
- you do not need to subdivide the reference, you just need to change the default setting to Nearest face interpolated;
- to answer the main question that brought you here,
the mesh is flying because weights didnt transfer at all. This may have happened because the reference was not visible;
- as you may know, uv maps must have the same names to be merged when you join the body with the garment. Same applies for vertex color, right now there are two vertex color attributes because they were not joined. This will not be a problem if you transfer vertex paint instead of manually adding it ( by the way, the sampled color is not correct );
- the body in the scene was taken from a lower lod, not lod0. They differ in polycount, so this is something you must not do. Instead, you can re-purpose the reference ( if possible ), duplicate a body part under the rig or append a nude body part. In this case, the reference will do. So select it, in Edit mode select everything with A, Mesh - Merge - By distance. Enable X-ray, select all parts of the body covered by clothing, delete them;
- when making uv_0 for your garment, you should always prioritize the predetermined placement of uvs. This is a top, so it makes sense to put its uvs in the area where the front's and the back's uvs of the upper body that you just deleted were. Putting everything in that bottom right corner leads to CAS full of items that cannot be used together;
- once done with data transfer and uv_0, join the mesh with the garment, give it the right cut and test in-game to see if it works right. Only once it does you bake textures and make lods;
- textures should be baked with the body in the scene + the floor. Both create extra shadows and make the bake result look less flat;
- do not import the same blend in all lods, it puts a lot of strain on the computer;
- instead of cloning a nude body part, changing tags, removing buffs, just clone a similar piece of clothing.
This video shows a basic process of garment adaptation in blender 3.6 and how to make maps as well. It is not a proper tutorial, but it will give you an idea of the correct order. Note that this is a start-to-finish process, meaning you do not need to do anything that isnt shown ( like vertex paint, transfer weights in Weight paint, etc ). The only thing I didnt show was how to bake textures from highpoly to lowpoly and how to set up materials
