Set axes in 3d plot

edit

You can write your own python function to draw axes, something like:

def axes(xmin=-1,xmax=1,ymin=-1,ymax=1,zmin=-1,zmax=1,**kwds):
    ex = vector((1,0,0))
    ey = vector((0,1,0))
    ez = vector((0,0,1))
    G =  line3d([xmin*ex,xmax*ex],**kwds)
    G += line3d([ymin*ey,ymax*ey],**kwds)
    G += line3d([zmin*ez,zmax*ez],**kwds)
    return G

axes(xmax=2,zmax=4,color='red',thickness=2).show()