I'm a bit stuck here with my underwear replacements. I know how to find the right property sets or textures and can make default replacements, so the basics are clear, but I've only replaced things with custom meshes before where I had the CRES/SHPE added to my file and could just drag them over into the 3D ID.

I had the idea to just open the 3D ID of the outfit I wanna use the mesh of and copy all the numbers over. It's just always hard to find out what part of it actually went wrong when trying around blindly, so I'm coming here to ask stupid questions first.

I can help you if you tell me exactly what you're looking for. tell me in exact words what you want to do, preferably if you have a picture, if not i can still help you if you tell me specifically what you're trying to do.

I'm not really doing anything in particular here, I just wanna know. I was default replacing underwear, and most underwear uses the same mesh, which is the "naked" one from the game for all the regular under- and swimwear. So does most the custom underwear you could download to use for defaulting. How do you go about default replacing when you wanna use a recolour of something that's already in the game?

Say I wanna default afbodylacylingerie, which is the one with the heels (wtf), and want it to be the same mesh like the rest so I can go and slash on it whatever normal underwear I want.

So I add the property sets and 3D ID's of all the "afbodylacylingerie" recols that are in the game to a new package. Normally I'd also have a custom mesh in there, empty the 3D ID's and drag that in instead. It would then say "Resource node: [...]" and "Shape: [...]" in the first two lines followed by the instance (and whatever else is in that long string of numbers) of the custom mesh I'm using. When I want the 3D ID to point to a maxis mesh, then I don't have a custom mesh in the package and can't do that. I either have to find that mesh and extract it or do it some other way, and that's where I don't know how, and couldn't find a tutorial.

I can gladly help you,but it is so strenious trying to help you when you're not providing any pictures. I looked in the bodyshop and I only found one female underwear with some low heels. Is that the one you're trying to default? If yes well are you gonna change the mesh as well? If only textures ,well the only thing you need to do is extract those textures and make a new package. Get your new textures and replace maxis with them keeping the original names and then put it in your download folder. You don't need to mess with anything else. Just make sure your new texture do fall in the right places. Why can't you provide some pictures of the maxis and your textures? Otherwise it is like trying to help someone screaming for help but hiding somewhere and can't help them since we can't see them.

If I understand you correctly, you want to default replace the texture but not the mesh; you want to use an in-game mesh instead... right? I don't have much experience with default replacing... except I once did it by accident and ended up applying a new default mesh to the existing mesh in the game. This happened because I forgot the Fix Integrity step. I'm not sure if that's a helpful clue or not, but maybe it'll help you think of a way to fix your problem.

EDIT: I found this in another thread. It's for maternity, but I don't see why it wouldn't work for underwear. Thanks to Phaenoh for this!

You will need to open the Sims03.package file (its in Sims3D or something similar) of the basegame files. You are looking for the GMDC of the Maternitywear. It is likely named something like afBodyMaternity-ugly or something. Find all of them, I think there are 4 or 5. Extract them all. Then open up Sims07.package and find the related TXTRs, extract them as well. Then open up Sims08.package and find the LIFOs - 0 (the bigger ones) and extract those out as well.

Create a new package and include the GMDCs and the TXTRs. Don't do anything to that package except save. Don't 'Fix Integrity' EVER. This will be your default replacement package. Next 'Replace' the GMDC files with the meshes you want to use but be sure to rename the file back to what it was before you replaced it. Then if they had textures you liked use 'Build DXT' on top of the previous images, if you didn't like those, edit the LIFOs until they look like something you want to use and 'Build DXT' those files onto the TXTRs instead. Commit after every step. Hit Save. Test in game.

Just don't replace the GMDCs; use the ones for the Maxis mesh you want to use... and I think that should accomplish what you're trying to do. I think.

Because I thought I made it clear that I do wanna default with another mesh, not a texture replacement, and it has nothing to do with any particular outfit I could provide a picture of. The question is how I'd go about it IF I want to default replace a mesh - any mesh, I'm not doing it right now and don't plan to do it with any specific outfit - with another mesh. Which is not a custom one, but came with the game.

So I want to use an in game mesh, but another one. The underwear was only an example. I want to know how I'd replace some in game mesh with another in game mesh.

fakekeeps' post helped me now, though, thanks