January 22, 2024

How to set up a survey / contour plan in AutoCAD to use in Revit.

Christiaan Calitz | Application Engineer

Creating a survey / contour plan in AutoCAD

If you are creating a survey / contour plan for someone who intend to use the “create from import” option in Revit and use an AutoCAD survey drawing using CONTOUR LINES as a reference for levels, it’s important to note that the AutoCAD drawing must be set up and drawn in a certain way to enable Revit to create the Toposolid from the imported AutoCAD file, correctly and accurately.

In AutoCAD, the survey drawing must be set up as follows:

Primary contour lines must be created as Polylines.
The Polylines must set to the correct “Z” values, to indicate the height above sea level of the contour line.
The drawing should be checked in a 3D view to ensure that Polylines have the same elevation / start and end “Z” values.
Proper Layer protocol is very important and should be adhered to (i.e. Contours should be assigned to a contour layer, Property Lines to a Site layer etc.) when importing the AutoCAD file in Revit, Revit will prompt you with a section box of layers detected coming from AutoCAD and only contours should be selected to generate the surface.
Ideally survey data should project beyond the site, incorporating curb levels for street connections where applicable.
Spot heights should be provided for all boundary peg positions.

By adhering to the above guidelines, the AutoCAD drawing can be used as the “imported” option to generate the Toposolid surface in Autodesk Revit.