Exporting contour lines to a CAD file returns null elevation values in ArcGIS Pro

Description

When exporting contour lines to a CAD file in ArcGIS Pro, the elevation values are recorded as null. Elevation values are essential when working with 3D data and terrain modeling as they represent the height or depth of features relative to a defined vertical reference such as sea level.

The attribute table below shows elevation values recorded as null when the contour feature layer is exported to a CAD file using the Export To CAD tool in ArcGIS Pro.

Cause

The contour lines are multipart features. The Export To CAD tool does not properly translate elevation attributes from multipart features as multiple geometry parts are combined into a single record, leading to data loss during the export.

Solution or Workaround

Separate the multipart features into single-part features to retain the elevation values when exporting the contour lines to a CAD file.

1. Open the ArcGIS Pro project.
2. Separate the multipart features of the contour lines into single-part features using the Explode tool in ArcGIS Pro. Refer to ArcGIS Pro: Explode a multipart feature for instructions.
3. Export the single-part contour feature layer to a CAD file using the Export To CAD tool.

   Note:
   The contour feature layer must have elevation values stored in a field named 'Elevation' or 'Contour' for the Export To CAD tool to preserve these values when exporting to a CAD file.
   

   1. On the Analysis ribbon tab, in the Geoprocessing group, click Tools.
   2. In the Geoprocessing pane, search for and click Export To CAD (Conversion Tools).
   3. In the Export To CAD pane, for Input Features, select the contour feature layer from the drop-down menu. In this example, the feature layer 'Pigeon Forge 40 ft Contours' is selected.
   4. For Output Type, select the preferred CAD platform and file version for the output CAD file from the drop-down menu. In this example, DWG version 2018 is selected.
   5. For Output File, specify a name and location for the output CAD file.
   6. Optionally, check the Ignore Paths in Tables check box. Refer to ArcGIS Pro: Parameters for more information.
   7. Click Run.

Note:
To generate a 3D output when exporting a feature layer to a CAD file, include the CadType field in the attribute table and populate the field with the 3DPolyline value to define the CAD entity type of the output file. This ensures the features are correctly rendered as 3D polylines when imported into CAD software for accurate representation and manipulation of the data in a 3D environment.

The attribute table in ArcGIS Pro shows the elevation values are recorded when the contour lines are exported.