I have this wierd problem with this 3dgraphing prog I d/l. the code snipet is: For(I,1,GRID+1) For(J,1,GRID+1) RX(I,J-1)->U1 It says 'Error 13 Dimension' on the last line (around the j-1). Does this mean that part of RX isn't defined(or out of range)? If so, that makes no sense as RX is a huge matrix with each cell filled. Thanx, Dave PS: can u respond by e-mail please?