Many thanks again YasserSelima!nA couple of questions:nWhy use F_UDMI and not just a normal array?nDo I understand correctly that to save 3 values in the F_UDMI (v, X cord, Y cord )I have to set value 3 in the GUI? I include Y coord in the sort function so I only call x neighboring on the same side of the beam. nWhat datatype is v? in the define_grid_motion function there is: Node *v; Can I simply replace it with a integer number from 0 to N-1?nn