This is a followup post to episode 92 when I discussed 3D sketches in SolidWorks. As I mentioned, many people don't realize that you can extrude or cut with a 3D sketch as long as it is closed and it has a vector direction to extrude along. As you can see, selecting the 3D sketch will be a contour that creates a fill surface and your direction can use a linear edge or sketch. It will essentially perform a directional sweep but this direction option can be useful for 2D sketches as well, in the event you don't want to extrude or cut normal to the sketch plane.
I also mentioned that you could use this to cut a free form directional cut into a complex surface using the spline on surface command. This command can be found under Tools, Sketch Entities, Spline on Surface. Once launched, the command will begin a 3D sketch and allow sketching on a complex surface, which will automatically reference the spline points coincident with that surface. Once finished, sketch a straight line in the vector direction of the cut, which could be within the same 3D sketch, or select a linear edge of the part. Now launch the Cut Extrude tool and select the straight line as the direction component and select the spline on surface as the cut contour.
This is one of those features that may come in handy for those obscure applications so I thought I would add a visual aid to follow the podcast. By the way, in case you were curious, this was added back in SolidWorks 2004. ~Lou