Click the Features | Edit Polylines | Break Polyline command or the button or right-click a polyline or 3D polyline and click Break Polyline to break the selected polyline, 3D polyline or spline polyline into multiple polylines. The cursor changes to to indicate break mode. Click on the polyline, 3D polyline or spline polyline in the location where the line should be broken. For the command to be available, a single polyline, 3D polyline, or spline polyline must be selected. Spline polylines are converted to regular polylines after being broken apart. 3D polylines continue as 3D polylines.
The new polylines retain the line properties from the original polyline. If the object name has not been changed from the default Polyline, 3D Polyline, or Spline Polyline, the new objects are named Polyline. If the object name had been altered, the custom object name from the original polyline is retained for both new polylines.