AutoCAD Civil 3D

[#1]

Yeah.  I am using 2012.  What do you mean baseline?  The interactive function will take a long time, because of all the points every 5 feet for the entire corridor.

[#2 · Accepted solution]

Interactive really shouldn't take long at all if you don't have that many regions.

Here is an article I wrote which explains how you can use the extents.
http://www.civil4d.com/2009/09/magic-corridor-boundary/

[#3]

Works great.  Thank you.