### Spline interpolation varies hugely when variables are rescalled some 3d-lists ?

Dear all,

Here is short script:

(nbx, nby) = (74, ~~90)
~~90)

def fx(x):
return (0.5 + ~~x/2.5)
~~x/2.5)

def fy(y):
return (40*y)

zetaPlot = list_plot3d([(30 * (fx(x/nbx)-1/2)+1/2 , fy(y/nby), 5 * abs(zeta(fx(x/nbx) + I*fy(y/nby)))) for x in range(-nbx, nbx+1) for y in range(-nby, nby+1)], interpolation_type = 'spline')

zetaPlot.show()

Now modify the z-coordinate: replace "5 * abs(zeta...)" by "abs(zeta...)"
The resulting graph is essentially flat. Can anyone tell me what is happening there?
Also, I would like to get rid of my scaling parameters 30 and 5 by using frame_aspect_ratio, to get cleaner code and a better annoted frame, but I don't seem to understand how to do it.

A great many thanks for anyone who would take the time to teach me that, it is some hours that I'm struggling with some docs and examples without having reached much --

Best, Olivier