Thanks, piever: first trick (line_z) helps!
Second answer – maybe I was not clear… What I meant is: consider a surface plot of the Rosenbrock function:
return (1-x)^2 + 100*(y-x^2)^2
x = linspace(-2,2)
y = linspace(-1,3)
a: I want to add contour lines in the plot (that used to be possible, but I cannot find the keyword now (i.e., instead of “:surface”)
b: Often, the surface + contour plots don’t show off so well – typically when the surface hides the contours. So – how can I offset the z-position of the contours from z=0 to, say, z = -500?