# This is a 3D polyline. It turn like half a circle in the plan +X+Y
# and for each segment, the line lift in the air. It make like a rought
# toronado made with 4 segements. How can I transforme this line in a
# nice and smouth 3D curve ?
polyline p \
cos(0) sin(0) 0 \
cos(pi/4) sin(pi/4) 1 \
cos(pi/2) sin(pi/2) 2 \
cos(3*pi/4) sin(3*pi/4) 3 \
cos(pi) sin(pi) 4
Is somebody can give me a hint ?