[Maxima-discuss] How to do this in plot3d?

[Peter v. S. <pet...@gm...>]

Hello,
I have a function z=f(x,y) and I would like to plot3d it in the x,y=0,z
plane, in the x=a,y,z plane and in the x=a,y=b,z plane.
Maxima refuses something like plot3d(f(x,y),[x,p,q],[y,0,0],[z,r,s]) for
the y. Only a range of y is accepted.
I need a box in which the several box planes have curves of f(x,y) - and
only that.
So, nothing 3d for the rest.
How can I do that?
with friendly greetings,
Peter