From CurvesKeyCreator \ Create \ Polyline \ From-Curves
Location: Create>Polyline>From Curves
Use this feature to create a polyline from contiguous sets of curve entities including lines, arcs, bi-cubic splines, NURBS splines, and polylines. To provide control of the quality of curved sections (number of segments) faceting parameters have been included in the dialog.
This function will automatically order entities selected using methods other than chain. Polylines are terminated at points where multiple curves branch and separate polylines are formed from sets of curves that do not meet.
Using the Function:
Create Closed Polyline from curves that close
When checked, a closed polyline will be created if the reference curves that you select for the chain form a closed profile. You are able to fill this closed polyline by checking the Fill Closed polylines with system fill color setting. The current system color for filled polylines will be used when the polyline is created.
Delete selected Curves
When checked, the reference curves that you specify for the chain will be deleted after the polyline is created.