You can merge new or existing drawing object geometry with a feature. If you have extracted the geometry from a feature to edit it using AutoCAD, you must update the feature geometry when you are finished editing.
You can use this command to combine spatially connected entities. For example, you can use a line and an arc to update the geometry of a single feature (resulting in one linestring or polyline). If the data store of a feature does not support curves, this command transforms the curves into line segments.