Inside our Utility Model.dwg file, we’ll want to create a new Surface model that will represent our complete proposed built environment. Although we have created a comprehensive SRF - Proposed Grade - Residential Subdivision Surface model that will represent our proposed portion of the built environment, we’ll need to create a new surface that combines both existing and proposed conditions to more clearly understand how our entire residential subdivision design will drain during rain events.

That said, we’ll use the following steps (similar to those defined in previous chapters) to create a full future-built Surface model that we can use to analyze and identify key locations where we’ll need to place inlets and pipes:

1. Open up the toolspace from the Home ribbon.
2. Navigate to Surfaces within the Prospector tab.
3. Right-click and select the Create Surfaces… option.
...