Big Circle

Ok, Im making a map based of the blood-type games from Age of Empires, and I want the terrain to look like it did in Soilder Store. So, I need a REALLY big circle, how can I make a really big circle? the biggest pre set one is way too small, and if I try by hand, I also get it all lopsided...how can I accomplish this?

zoom out really really far. if the map disappears just ctrl scroll to get it back.

put down a circle doodad first. like.. circle of power, then make that reaaaly big, and build the terrain around that. gl

ooh...I tried that with the unit circle of power, but it was mini, I bet doodad one can be much bigger tho, duh ><

Sorry for double post, but when I do the doodad thing, then lay the terrain down, which works great BTW, but then after I go to select the circle of power and delete, my comp freezes then goes to blue screen of death and says somthing about memory. I dunno why it does it, Im only selecting the circle of power, maybe its too big =/

I dont know why it would do that... if it is too big, make it smaller b4 deleting it :D

Once again, thank you. I must really suck at terraining to not think of these things lol