how i can remove the terrain easily from my subterranean part of the building

[katie.dim]

Hello again 

I need help to understand what are my option in order to easily crop the terrain from my house. I am tying to create boxes and to subtract but i have particular forms and it is hard to do it without  ruin the terrain. 

[lrm]

Create solid objects that can be subtracted from the full solid of the terrain. 

Start by creating closed polylines for the base of the main building and the garage and extrdue them upwards such that they penetrate the terrain surface.  Subtract these solids from the terrain solid.

The next goal is to create a solid that defines the void of the tunnel connecting the buildng and the garage. Start by creating two 3dpolys (shown in yellow) and loft a surface between them.  Do the same for the two green 3dpolys. This wil yield surfaces for the ceiling and floor of the tunnel.  Create a single closed 3dpoly for the floor of the tunnel (yellow lines but conected at their ends) and extrude it upwards.  Use surfsculpt to create a solid for the tunnel from these surfaces that define a watertight volume.

 

[katie.dim]

THANK YOU