I think unfortunately nobody implemented that yet. You can work
around this by using the text3d command to explicitly place
a label, like this:
sage: var('x,y');
sage: plot3d(sin(x*y),(x,-1,1),(y,-2,2)) + text3d("X Axis",(0,-2,-1))
(When this feature is implemented, it will in fact be implemented by
just calling text3d.) I hope somebody will implement it; I doubt
it would be difficult.
- William
So it's not perfect, but for me is quite a help at keeping oriented
with what is where when I'm looking at it. Though I'm not sure if it's
good enough for you needs.
Erik