It looks like you have a corridor running through on the SW-NE geom and a civil cell overlaid at the end. You should really pull the start of the corridor back onto the end of the end of the control geom for the civil cell. Then add the civil cell as a clipping refernce to the corridor running NW-SE,
Clipping is triggered in a civil cell by defining the primary surface terrain as a clipping reference for the corridor, when placing this terrain and all linear templates are then added as corridor clipping refernces to the selected corridor.
The presentation and workshop from the BLC2013 should be available on the Learn Server. Information on how to access these is included in the sticky post 'SELECTseries 3 WORKSHOPS AVAILABLE!'
communities.bentley.com/.../84935.aspx
I hope this helps.
Regards
Ian