How do I make both sides of my mesh's faces opaque?

Well, there is an option in blender for it to display both faces but that will not solve anything in game.

Blender only shows the faces where the normals are facing. And like the you usually face outside, then the inside is transparent.

What I usually do it I select the parts where I want to have the inside visible, then -> duplicate -> inverse normals.
I sometimes slightly scale the duplicate down but I am not sure it helps anything.

The problem of the technique is obviously that you multiply the number of vertices in your mesh and also if you want to modify those parts later on it is sometimes a pain to select properly.

But all in all it works.

Hi, please shared the .blend and .package file so someone can take a look at them.

mm i don't remember an outfit mesh to have that many groups. Usually they have 3. What did you clone? I suggest cloning a BG swimsuit, export its mesh, check the group names and cut numbers. Also, you don't really need to cut your dress' mesh into groups, just have it all together on the top mesh group whilst leaving the legs untouched. Then you can change the category tags of it.

I remember seeing a similar issue with the black lines. Hopefully after joining the dress they will disapear, have you checked in game to see if those are visible?

Well.. why would you have something divided into more groups than necessary. I think it'd be much easier to start of.

I'm not sure how to explain it or paraphrase it. You've cut the dress into several parts. You don't need to do that, keep all the clothing pieces into one group and only leave the part of the legs on their correspondent mesh groups.

you can have the legs in the dress mesh. you can have it all in one group. putting it into more just makes it harder for yourself. if you restart and import it all over again, you can select the dress and copy it and inverse it so there's texture inside. next you can append the body.. then you can join them all together. that would work lol

Alternatively, you could use this tutorial and just clone an item with one mesh group so it's easier to work with.

novasim there's no full outfits of 1 mesh group. If you've joined everything into one group you're only updating that mesh group from the original package, the rest of the groups (leg parts) are still there so you'll have extra geometry on those parts. Joining fixed your issue because that was what suggested, but you should delete the geometry of the legs that are divided into the other groups.