Reducing faces.

[andylegate]

I know you can take, lets say, a cylinder, and flip the normals so that it's the inside of the mesh that is shown.

But let's say you have a mesh that you imported, like a obj. Now, it's double sided, meaning the walls of both the inside and outside are shown, but in essence the walls are planes, they have no thickness.
You only want the inside faces, not the outside ones. How do you do that? No sense in having the outside walls rendered since the Avatar will never be out there to see them. This will help lower the poly count and improve game performance.

[Nadnerb]

Well, just make sure the normals point inwards... and if there is another set pointing outwards.. you ah.. delete them? I'm not sure what the question is here... A face can't be drawn more than once per frame, so even if it is set to be double sided, so this shouldn't affect performance.. If your faces are drawing doublesided and you don't want them to, then check that the "TwoSide" property is off in UV edit mode. (in the editing buttons [F9] while you're in uv edit mode [F])

[andylegate]

Oh I've gotten it to where it only draws on the inside. The problem was that this is a mesh that was made in 3DSMax, and upon import, everything was doublesided. Even the verticies. Weird.

The reason I was concerned, is that the judges for the competition are going to look at your poly count on your Age. I haven't gotten answer back yet on what they consider too high, etc. But I was concerned about it trying to draw on the outside too, which would slow things down. Well, not on my machine anyways, but on slower end machines.

However, I took care of the problem by selecting all the outside faces, and told it to seperate, then deleted that new mesh (don't ask me how it did that, it doesn't make sense to me either, I mean a 2D object, is 2D right?). But it worked for me.

[Jojon]

Err, so in other words, two-sided faces in Blender are not two-sided faces at all, but pairs of opposite-facing ones, is that it?

Normally a face that you can see from both sides would still be a single face and use no more vertices than a singe-sided one. The only reason for faces to be single-sided (that I can see), is that it allows for an easy pass of rough face culling in real-time rendering.

I'm guessing this all says more about the object you imported than anything else... :7

[andylegate]

I don't think it was really the object itself, but perhaps the import method that Blender used. I was exported from 3DSMax as a OBJ file. And of course imported into blender as one. I've got a feeling for some reason it put in double verticies. I have that happen all the time when I import STL files.

[Moiety Jean]

I'm guessing it wouldn't have worked to use "remove doubles," then?