Link a DWG File and Use Shared Coordinates

When the survey point or the project base point is already defined using grid (GIS) coordinates from the civil engineer, you can link a site DWG file and use those coordinates to establish shared coordinates for accurate positioning of the model on the site.

Video: Using Geographic Data from a Linked DWG File

This procedure assumes that the following tasks have been completed:

1. Obtain GIS coordinates from the civil engineer.

   If you have access to AutoCAD Civil 3D, you can open the DWG file to get the following coordinates for the selected survey point:

   • Grid Northing
   • Grid Easting

   For easy reference, copy and paste these values into a text file.

2. In the Revit model, use these coordinates to specify coordinates at the survey point or the project base point:
   1. In the site plan view, select the survey point or the project base point, unclip it, and position it as desired in relation to the model.
   2. Using the Specify Coordinates at Point tool, select the point at the center of the unclipped point. In the Specify Shared Coordinates dialog, enter the GIS coordinates for North/South (Grid Northing) and East/West (Grid Easting). Click OK.
      Note: Enter coordinates using units that match the Length project units specified for Revit. As an alternative, enter the coordinates with a unit indicator (such as m for meters), and Revit converts the value automatically to the correct project units.
3. Select the point again, and confirm that the correct GIS coordinates display.

   The point can be clipped or unclipped when you link the DWG file.

When the survey point or the project base point uses the GIS coordinates, you can then link the site DWG file using shared coordinates.

To link the DWG file using shared coordinates

1. Click Insert tabLink panel (Link CAD).
2. In the Link CAD Formats dialog, for Files of type, select DWG Files (*.dwg).
3. Navigate to the folder that contains the file to link, and select the file.
4. For Positioning, select Auto - By Shared Coordinates.
5. Specify other options, as appropriate.

   See Import and Link Options.

6. Click Open.

   A dialog indicates that the model and the link use different coordinate systems. Although the survey point or the project base point uses the correct coordinates, Revit does not know which grid coordinate system to use.

7. In the dialog, click Align.
   Note: You would use the Position center to center option if you aren't sure whether the shared coordinates are correctly set. In that case, you must manually align the DWG file and then acquire its coordinates.

   The DWG file is linked to the model, and its geolocation reference point is aligned to the survey point or the project base point.

8. To confirm the geographic location of the Revit model, click Manage tabProject Location panel (Location).

   On the Location tab, for Define Location by, the option Get Geolocation from Survey Point is selected. The GIS Coordinate System, Latitude, and Longitude fields display geolocation information acquired from the DWG file.

If you need to push the coordinates to other models that are linked to this Revit model, use the Publish Coordinates tool.

When exporting this model to DWG or DXF, you can set an option to include the shared coordinates as part of the export.