Ok, here's a working VB script that will run through a stack of closed planar curves and will determine which are at the same z height, totaling their areas. I've had to sort the curves in z height order - for some reason if the curves are out of order, the script screws up the z height list... can anyone explain why?
http://groups.google.com/group/grasshopper3d/web/areaCalculate.ghx?hl=en
