Using Inkscape, I'm trying to remove the diagonal straight line that runs through the circle, but none of the boolean tools or path editing tools seem to work. (The two objects are a Circle and a Bezier path that's had Taper and Perspective effects added).
When I try to apply Boolean operations, I either end up losing one of the two objects (I guess the "cutting tool" gets discarded?) or else I can't cleanly eliminate the diagonal line without altering the shape of the Bezier path. Similarly, using the path editing tools, I've been unable to remove that segment without altering the path.