Centerline of Corridor Surface drops to 0 elevation... Why?

[Dan Johnson]

I have a corridor surface that did work properly but over the course of a weeks worth of edits I seem to have lost track of when this error happened to cause my corridor surface to drop to 0 elevation only on the ends of my corridor and only on the centerline and not on the whole width. It drops exactly 10' from the edge of the corridor. I have attached a photo to better explain this.

BTW I'm using Civil 3D 2012

[jpaulsen]

I have seen something similar when the corridor extends beyond the limits of the profile.

[Dan Johnson]

Yep. Wouldn't ya know i was short just a wee-litttle-bit. Note to self: extend finish grade profile at least 5-10 feet beyong corridor if not longer.

[tntdraftsol]

I have even had this happen when the corridor is within the limits of the profile. I just go into the parameters and back it off a hundreth of a foot on both ends and then no problems.