Spiral Ramps?

FlavorRage

L4: Comfortable Member
Oct 12, 2008
197
57
Hi guys!

I need some help. I'm trying to make a koth map where the koth is underwater, on a collapsed section of bridge. The area is round (think watchtower). I want some earthen ramps going up to the parts of the bridge still standing, but I have no idea how to curve them.

tl;dr: How do I make curved displacement ramps as seen in offblast and hydro?