Autodesk CIVIL3D - CIVILDESIGNCOMP 2007 SLM CD Tutorials Manual page 733

10 Click two points to create a rectangle that is outside of the current
geometry. In Content Builder, change the name Rectangular Profile to
Outer Wall. A rectangular profile is drawn.
11 Draw a second rectangular profile within the first. Change its name to
Inner Wall. There are now two rectangular profiles.
12 Right-click Top of Box
left side of the outer rectangle, then the left side of the inner rectangle.
Then click the top side of the outer rectangle and the top side of the inner
rectangle. The distance between the outer wall and inner wall on the left
side is set to always match the distance between the outer wall and inner
wall on the top side.
Exercise 3: Defining the Vault Box Geometry | 721
Add Constraints Equal Distance. Click the