you do not need multiple angles of a doodad, because you can change the angle in the world editor, only submit one of these walls
I'M SORRY dude, i respect you (even gave you +rep very recently), 67chrome and the others, very much, honestly.
BUT!
This guy right here has done something that is
Very useful! So do not turn him down please.
Simply because
while most mapmakers are totally okay with using the same old methods over and over and over again, as in, using doodads for everything that is meant to participate in the eye candy or path blocking (often referred to as "environment"), there are some other mapmakers who want an "environment" that can be destroyed, repaired, etc: they need
units!
I don't know if you ever tried to make a map where you simply want to allow players to build walls. "Lol easy" you say? Not with imports.
Because:
-you import your wall, that exists only in one version turned 90° for example,
-and you make a vertical and a horizontal wall unit,
->you have
one of the two that is gonna look very bad when you select it in the build menu ingame and you want to place it. In this example it's the horizontal one: it will look just like the vertical one (90°) and the player is confused.
-Now, thanks to Mephestrial, problem solved! Give him a medal!