Z values persist despite being disabled when exporting a shapefile to CAD data

Description

Exporting a 3D shapefile with Z values to CAD data using the Export To CAD tool, even after disabling the Z values option in the Environment Settings, retains the Z values.
In a case where both Z and M values are enabled, the resulting CAD data after the conversion removes the M value, but not the Z value. In some instances, the issue still occurs even after the Check Geometry and the Repair Geometry tools are run on the data to check for geometry problems.

Cause

Exporting a shapefile which has Z value features to a CAD format creates Z-aware features, even though there are no elevation values associated with the data. The data to be converted must be imported into a file or personal geodatabase.  Fields that control the export process are ignored if the input data is in a shapefile format, hence the Export to CAD tool ignores settings such as removing Z values.

Solution or Workaround

The input shapefile must be converted to a geodatabase feature class, and the Z and M values must be removed by modifying the values in the Environments Settings. To convert the 3D with Z and M data to plain 2D data, follow the steps below:

1. Run the Feature Class to Feature Class tool to convert the shapefile with Z features to a geodatabase feature class. In the Environment Settings for the tool, set the Output has M Values option to Disabled and the Output has Z Values option to Disabled as well. These settings are not honored in the Export To CAD tool, since the tool simply accepts the input data format with no changes. Refer to the following knowledgebase article for more details: How To: Remove Z- and/or M-values from a feature class.

2. Run the Export to CAD tool to export the geodatabase feature class to CAD data. The output CAD file consists of 2D features without the Z values.