Break Polyline
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.