Seems like a bug on Autocad Civil 3D 2013. I followed all the tutorials to design a circular vertical curve on a profile and it just dont work. I put circular on settings, click on circular curve by PVI button, the software even ask the radius and it end up designing a parabollic curve. Could someone please help me?
I just tried it and it worked just fine for me. Is that it "looks" like a parabola? Because most likely your profile view has a vertical exageration to it. Set the exageration to1 in the profile view style and check it again. After doing that, draw a 3 point circle on the profile and see if they are the same.