Bringing AutoCAD Surfaces into ArcGIS

Let’s just say you’ve done a lot of manipulation of a surface in AutoCAD, and you would now like to see it in ArcGIS. Jon Lefers at AE2S is a pretty good resource to turn to when it comes to working between AutoCAD and ArcGIS. And he is nice enough to share his methodology. This from Jon:

  1. In the Toolspace, Prospector tab, right-click the surface, and either select “Edit Surface Style” and turn on Triangles and the Border for the surface (or select a surface style theme with that already on).1
  2. Extract the objects from the surface under Surfaces / Utilities / Extract Objects from surface (triangles, border, etc., and also contours if you want to show them in ArcGIS).  If this menu bar doesn’t show up, click on the little down arrow next to Civil 3D and select “Show Menu Bar”.2

     

  3. AutoCAD represents boundaries as 3D polylines, so in order to eventually see it as a polygon, you first need to convert the 3D polyline to a 2D polyline (command is in the design pulldown):3

    Then convert the 2D polyline to a polygon in AutoCAD (command: MAPPOLYLINETOPOLYGON).  If you have holes in your surface, you need to first group your polylines (command: GROUP) before converting to a polygon.

  4. Next, when doing map export, go to:4

    And select:

    5

     

  5. Bring in your triangle 3D faces as polygons, and your boundary as a polygon.
  6. Create a TIN in ArcGIS using the TIN triangles as the default polygon option, and the boundary (no height elevation needed). Voila!6

Leave a Reply

Your email address will not be published. Required fields are marked *