The following options are available:
1) "Edit Surface" dialog box:
Activate the "Hinges" tab (see Image 01) and use the button to create a new line hinge.
2) Types for Lines - Data Navigator:
Right-click "Line Hinges" under "Types for Lines" in the Data Navigator, create a new line hinge, and assign it to the surface and line; see Image 02.
3) Types for Lines - Menu Bar:
It is also possible to create a line hinge using the menu "Insert" → "Types for Lines" → "Line Hinges" → "Dialog Box".