I'm working on a new outfit and tweaking it in Blender. For some reason though whenever I use Object > Mirror on a few specific pieces of the outfit the faces get turned inside out, making the outside invisible and the inside visible from the other side.
It seems to happen with those exact pieces regardless of how I do it.
The faces appear perfectly fine until I either export it and view it in Nifskope, or I use Apply Size and Scale (in which case the mesh appears all black in Blender, but still has the same inside out appearance once exported).

Does anyone know what would cause this?

Isn't that exactly what's supposed to happen? Each triangle in a mesh has its face toward you if the sequence of its vertices runs counter-clockwise. When you mirror it, that sequence is clockwise and so the face is away from you. Just select all the faces in the mirrored copy and flip them before you join it back to the main mesh.

That happens in 3ds max as well when mirroring stuff. You need to apply transforms before export. Don't know how it is called in Blender (reset x form in max).

Wait, one of us is misunderstanding the other.
So first, it's common knowledge that in a proper mesh the outside faces appear solid, while the inside faces often appear invisible (so if the camera were placed inside of a sphere mesh, you would see nothing at all). I'm not being a [censored] saying that, I'm sure you already know it, but it gets at what the exact issue is.
What I'm trying to do is take an asymetrical belt which has different stuff on each side, and mirror so the stuff switches sides. When I do this though, not only does it switch sides like it should, but the faces also turn inside out so that the outside is invisible, but the inside is solid, so when you look at it all you see is the inside of the opposite side.


I think you're referring to Apply Scale and Rotation. Doing that doesn't fix the issue though. It looks exactly the same after export whether I use that or not.
If there really is something else, that would make this really easy though anyone know?

They both are understanding you fine -- the thing is when you use the mirror tool it will create a mirror image which means flipping the normals also to face each other (ie. if you look in a mirror you will see your reflection looking back at you -Not a reverse image looking away from you ! - After mirroring the piece you need to then Face or Flip the normals or whatever it is called in Blender which will then flip all of the normals of that piece to face the opposite direction which is what you are wanting.

Perhaps THis will explain things and how to fixx it a bit better -- http://www.blender3dclub.com/index.php?name=News&file=article&sid=16&theme=Printer

I never thought Phitt misunderstood me, and I said I wasn't sure if either Ghastley was misunderstanding me or I was misunderstanding him.
Thanks for the link though, you were both right. Simply pressing ctrl-n in edit mode fixed it.

No problem - just was trying to explain what they meant - since I also use Max not Blender was not sure what keys to use or what they called the process but glad the link included it for you !