There's this male torso default replacement by nanashihito, which I love, but unfortunately it often causes issues with bracelets and necklaces glitching through the sim. This isn't always an issue though but currently I don't have it in my game. Yesterday I thought that it would be really cool if it was non-default, because then I could install it again and only apply it on the sims I want to rather than everyone. However, I'm not a modder and I don't know if such a conversion would be easy (or at all possible), but I'd gladly give it a try, if I knew how. If anyone has done anything similar before, please feel free to let me know :D

Open the package with S3PE and export the geom. Use Meshing Tool Kit (MTK) to convert geom to TSRW .wso. Use the seam fixer in MTK (to be sure seams are good). You can also seam fix as geom if you prefer.

Open a male nude top in TSRW. Export the L1 .wso. Use that as a reference to add morphs to your mesh in MTK. Import the new mesh to your work.

Right tabs, Project. Scroll to and open Categories. Check or uncheck boxes to set the top for any categories you want in CAS.

Top tabs, EDIT> Project Contents> Export> To Package. Open your new package in s3pe. Top tabs, right click Resource> Select all. Again right click Resource> Compressed. Save your package.

TSRW automatically renumbers reskeys and CASP.

Should be far more simple - just clone the item in S3OC with Renumber ticked. That's it, it will be a standalone CASP that no longer overwrites any default resources.

Wow, thank you both so much!

Ok, unfortunately I can't use S3OC to do this, because the package files only contain a GEOM resource (it appears that S3OC needs a CASP resource to work). I'll try LadySmoks method instead. Hopefully it won't be too difficult.

A question for you... How do you clone morphable items in s3oc? I have tried this, and the morphs generally explode spectacularly in game, since vertex ID's are never the same, even if vertices count might be.

Ah right, that does add an extra step.
The way you'd do it with S3OC would be to clone whatever is being replaced (amTopNude) with Renumber unticked, import the default replacement package into it, then clone that with renumber ticked


I've never encountered this - EA items clone perfectly, so I would expect good CC to also do so. Do you have any example of CC that breaks in this way?
My best guess would be if those items used non-standard IDs (outside of the EA range for those items) or missing some kind of data that S3OC tries to implement. Only the instance IDs of the resources are modified by cloning, so actual mesh data like vertex IDs shouldn't be touched at all.

Ok, so I managed to do it by following LadySmoks's instructions. It was a little bit daunting at first (plus I made a mistake, which took me some time to realize) but I'm glad I did it, because I learned a little bit about how cc is made! Unfortunately, the S3OC method didn't make the body replacement non-default for some reason (it was the first time I've ever used S3OC so please excuse me ) but anyway thank you both for your help! I'm so happy to be able to have one of my most favorite pieces of cc back in my game! <3

OK... I see what you're doing. You're using S3OC to just clone an exsisting cc package. But, my uses are to replace meshes with custom, which need thier own morph bgeos and bblns, etc, to match the custom meshes. At the same time, how do hair makers like you, make default replacements? I've seen many that seem to have been generated using s3oc, which would mean a new mesh and morphs (if the hair has morphs).

In the case of OP, the packages only contain an L1 geom with a default reskey. I wouldn't mind understanding how you use s3oc, but this probably isn't the place for that.

For OP's purposes, renumbering a default replacement is enough to make it standalone. I neglected to check the CC they were referring to, but it just needs to be reunited with its CASP to do that.
I suspect it didn't work either from not removing the IsHiddenInCAS flag or mixing up the tick/untick Renumber steps.
It's basically just a shortcut over repurposing the parts, useful for more complicated defaults.

Vice-versa, making a standalone into a default, is the same concept. Replace the CASP instance with the EA one, and it's more or less done.
The one flaw is that existing sims will wear the new mesh with the old texture, due to those textures being referenced in their outfit. If the replacement has a different number of recolourable channels than the original, this will also look strange.
Resolving this is where each default creator does things a little differently.