The split face operator takes a curve or list of curves, projects them onto the selected face and splits the face into multiple faces using the projected curves as the boundaries.
To create a solid lofted design feature:
Select Split face from the solid wizard or the solid toolbar.
Select a face name
in the Face drop down list or
click the Pick surface
button and select the face in the
graphics window.
Select the curve
name in the Curve drop down list
and click the add
button, or click the pick curve
button and select the curves in the graphics window.
Repeat step 3 if you want to use more than one curve to split the face.
Click the Preview button to confirm that the surface is correct.
Click OK or Finish.