Follow the steps below when using the Surfaces>Edge Curves function.
Using the Function:
Select Edge Curves from the Create>Surfaces submenu.
The Edge Curve Surface dialog appears, from which you are able to specify how the edge curve surface will be applied. Select OK once the available settings have been configured.
Depending upon what was selected under Number of Edges, you will be prompted to indicate either three or four boundary curves.
The Edge Curves surface is then created based upon the boundary curves you selected and the specifications made through the Edge Curve Surface dialog.