Creating a Toposurface by Instance
Creating a toposurface by instance requires that you import a CAD file. After you do so, you can go to the Toposurface command, which offers the choice to use an imported instance to drape a surface from Revit.
To get started, you can either choose a site that was created in CAD that you want to experiment with, or you can go to the book's web page at www.sybex.com/go/revit2012ner. From there, you can browse to Chapter 18 and find the file called contours.dwg.
The first thing you need to do is think about coordinates. That's right: coordinates. You're bringing in a file from AutoCAD, right? How do you know where this site will be placed? You must consider two things: where the project base point is in AutoCAD, ...