Diamond-shaped Beampipe Aperture

Required for North-Area studies. A diamond shaped beam pipe. Possibly parameterised as the height and width at the points.

A possibility would also be to have curved edges with a radius of curvature, although the geometry would be more complicated. Geant4 would very much have problems visualising a shape with 4 or 5 Boolean combinations… Tradeoff would be an extruded solid.