To Install the ArcGIS Projection Engine Data

It is recommended to install the ArcGIS Projection Engine Data before bringing ArcGIS data into your drawing with the Autodesk Connector for ArcGIS. The Projection Engine Data prevents a co-ordinate offset due to any datum transformation occurring when you bring ArcGIS data into a drawing. This offset due to datum transformation may occur when using co-ordinate systems that haven't got an EPSG code or if any data transformation occurs between co-ordinate systems.

Note: To prevent a co-ordinate offset issue from occurring when you save back to ArcGIS, use a co-ordinate system that has an EPSG code.

1. Close Civil 3D.
2. Go to https://developers.arcgis.com/downloads.
3. Sign in to ArcGIS.
4. On the Downloads tab, under Other, click Projection Engine Data.
5. On the Projection Engine Data page, download the latest Projection Engine Data.
6. Unzip the downloaded file to a local folder such as C:\Users\<username>\Downloads.

   By default additional subfolders are added to the folder name when the content is unzipped. For example, C:\Users\<username>\Downloads\ArcGIS_Runtime_Projection_Engine_Data_100_5_0\PEDataRuntime.

7. Click the Windows Start button to display the Search Programs and Files box.
8. Enter regedit and press Enter to open the Registry Editor.
9. Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Autodesk\AutoCAD\<version>\ACAD-<version>. For example, HKEY_LOCAL_MACHINE\SOFTWARE\Autodesk\AutoCAD\R24.1\ACAD-5100:409.
10. Double-click the registry item ArcGISProjectionDir to open it.
    Note: If this registry item does not exist, create a new String Value in that location named ArcGISProjectionDir.
11. For the Value Data, enter the folder that contains the unzipped files, for example, C:\Users\<username>\Downloads\ArcGIS_Runtime_Projection_Engine_Data_100_5_0\PEDataRuntime.
12. Click OK.