MERGING CORRIDOR SURFACE WITH EXISTING TOPO SURFACE (for rendering composited surfac)

[Old Timer]

I have completed the designs of a Corridor and generated Corridor Surfaces and Existing Ground Surfaces

 

My goal is to present a rendered "walk through" of the composited surfaces (Proposed Corridor and Existing Ground) with a "hole" on the Existing Ground Surface where the Corridor Surface "fits in"

(this is the "best" way to review the overall design)

 

Is there an easy way ?

OR

Do I need to extract the daylight lines from the Corridor and apply this to the Existing Ground Surface ( and "cut-out" the hole from the Existing Ground Surface) ?

 

Just don't want to spend four hours "cutting the hole" in the Existing Ground Surface

"merge surfaces" command, or do I need to Render the two surfaces at the same time ?

[Old Timer]

I guess the SURFACE "MASK" command was the command I was looking for.

I took the Daylight Lines from the Corridor and used them as the Inner Boundary to maks the Original Topo Surface

 

Now I have a "composited" surface to render

 

However, now everytime I rebuild/edit the Corridor, am I going to have to perform this exercise again ?

OR

Is there a way to LINK to Corridor Daylight Line to the Masked Inner Boundary (of the Original Topo Surface) ?