I had a member at my last user group meeting pose this problem:

I have a cylindrical part that has bosses extruded out of the side of the cylinder normal to one of the primary planes, and a fixed offset from the cylinder.  I've sketched the cylinder on the top plane and extruded.  Then on the front plane, I sketch the bosses and extrude from the surface to the proper height.  That much all works fine.  Now I need similar bosses on the other side of the cylinder.  How do I get SW to go the other direction?

Nobody at the meeting had an immediate solutions.

Check out the attached picture.

This is how it was accomplished:

Create the first two features exactly as detailed above.  Create a third sketch, also on the front plane.  Put anything in the sketch.  The sketch geometry is basically going to get trashed anyway.  Just a line will do.

Exit the sketch.

RMB on the sketch and "Edit sketch plane", move to the "Top" Plane.

RMB on the sketch again, "Edit sketch plane", move to the "Right" Plane

RMB on the sketch again, "Edit sketch plane", move to the "Front" Plane

At this point, it seems the sketch should be exactly as it originated, but that is not true.  The sketch has been inverted (front has become back, and back is the front) and rotated 90 degrees.  At this point, edit the sketch and make the appropriate sketch geometry.

Now making the "Extrude, From, Surface/Face/Plane" sees the cylindrical face to extrude "from" in the opposite direction.

The user had been using "Split Lines" on the face of the part to get the two halves of the cylinder to be seen as different faces, but the split lines were undesirable.

Any other solutions out there?