AutoCAD Civil 3D creates and maintains a point database file that contains all the point information in the project.
COGO points store the point number, name (optional), northing, easting, elevation, and description in each drawing.
You can also reference your own customized databases and use them to do the following:
- Substitute point elevation data when points are accessed through a point group.
- Substitute point raw description data.
To link these custom point databases to AutoCAD Civil 3D, create External Data References (XDRefs). For more information, see Creating an External Data Reference. An XDRef is a pointer to an entire column of data in a custom Microsoft Access database. All of the database entries must have a point number. Then, when you use an XDRef to get a value for a point, the point number is looked up in the custom database, and the value from the specified column is used instead of the original point value that is stored in the drawing.
XDRefs do not overwrite or alter the points in the drawing. Use the External Data Reference collection on the Settings tree in Toolspace to create and manage XDRefs.