How to plot vectors (e.g. presentation grid) so that the vertical axis become perpendicular to a curved surface? (Instead of always in the global horizontal and vertical axes).

is this not possible?

Not sure I understand the question. Here's what I think you're asking:

popt vect ugrid on

spoint x,y,z, <-a point on the surface snorm x,y,z <-a vector normal to the surface

view snorm rota x -90 repl

If your asking about mapping your results to another coordinate system, you need:

psys 5 <- a csys with one axis normal to the surface getc all vmag repl

Thanks, but these didn't do what I wanted to see.