As you may or may not know, polygons have two distinct sides. You can prove this to yourself
by flying around in the 3d view in the editor, and watch as you move from one side of a polygon to another. The
side you can see is the good one.
There may be times when you need to turn one around. If you are doing Zone Portals, this is likely
to happen to you. Zone Portals are generally 'sheets' which are just simple polygons (not part of a polyhedron,
or 3d brush, as such). These are easy to turn by hand.
If you are using UnrealEd 2 (the new one), AND your polygon is either
aligned to the X, Y, or Z axis, you can simply select the brush (not the surface, the brush, the polygon itself).
Right click, Transform, Mirror X (or Y, or Z). Then, Transform Permanently. That's it! You can also Rotate the
brush 180 degrees around any axis, if the brush is symetrical enough. Then Transform Permanently! Use that a LOT.
If your brush is tilted, you may have to be clever with which axis you choose, and if the brush's origin is not
in the center, you'll likely have to reposition it after Mirroring it. (Thanks to Wanderer for these tips)
If you are UnrealEd 1 (the original), OR your polygon is tilted, or in any way non-symetrical,
you may have an easier time using Vertex Editing. If you are doing tricky zone stuff like in my Advanced
Advanced Portal Techniques tutorial, your zone portals may not be symetrical enough. And, in UnrealEd 1, the
Transform Permanently function does not work. What we need is an untransformed polygon, and vertex editing will
do this for us:
Pick a view where the sheet is edge-on to you (looks like a line). Vertex edit: let's say you have a rectangle,
vertices A,B,C,D, and A & B are overlapped, as are C & D.
Drag vertex A out, which gives you a triangle.
Drag the one that was under A, namely B, out of the way too.
Now, drag the other end's vertices (C and D) to the spot where the first ones were, A & B's original position.
C and D overlapping again.
Then, drag A & B to where C & D were originally.
You now have the polygon reversed. Vertex editing ruins any surface alignment, so select the surface and hit F5
to fix it.
If anyone knows an easier way to do this, let me know.
If you want to turn a polygon around which is part of a brush, export the brush or level to t3d format. Find the
polygon. You can try flipping the signs on all the components of the Normal. You could also try reversing the order
the vertices are defined. I'm not really sure it that would override the normals.
