Trimming a Toposurface in Revit 2015

by Justin Doughty

When creating a Toposurface from an Import such as an AutoCAD DWG file, you may find that the Toposurface created does not maintain the same boundary as the original file.

This is due to the automatic conversion process automatically specifying boundary and internal points.

Below is an example of this, with the imported boundary highlighted:

The simplest way of trimming an existing Toposurface boundary is to use Split Surface in the Massing & Site tab:

Here we can use the Pick Line utility to specify the split line:

Then you just need to close the loop and select the green tick, creating a second surface.

Finally the easy bit. Pick the new surface and delete it: