A Ruled surface creates a linear surface between two curves. The curves can be open or closed, planar or non-planar. For closed curves, the starting points of the curves should line up or the surface may twist in odd ways.
Follow these steps to build a ruled surface:
You must have at least two curves before you can create a ruled surface flyout.
Use the Surface wizard or select Ruled from the surface toolbar.
Name the surface for future reference.
Pick the curve on one bounding edge of the surface, curve 1.
Continue picking curves either with the Pick button and mouse or from the drop down list. If you use the list, use the Plus button to add the curve to the list.
Use the Up, Down, Reverse, and Delete buttons to set the sequence and direction of the curves in the ruled surface.
Decide whether to set Reparameterize curves.
Click Preview to see how the current settings affect the surface. Make adjustments as necessary until the surface is how you want it.
Click Finish or OK.
An example of a ruled surface.