问题
When making a figure using the mplot3d package, three gray walls are automatically created and the axis ticks and grid lines are placed along these walls, as shown in this mplot3d example which I will be referring to later.
These walls are positioned such that they are placed slightly outside the given axis limits. For instance, as you can see in the figure of the referred example, the vertical grid walls stretch from slightly below 0 to slightly above 1. A negative side effect of this is that the bottom wall (the floor of the plot, if you will), is placed at a z coordinate slightly below 0. This makes it difficult to accurately read the grid. For instance, the red surface in the example figure hovers over the bottom wall, and therefore looks like it's positioned along y = 1.1 instead of its correct position of y = 1.
I've tried to find out how to change the position of these grid walls without success. Their colour can be changed using the axis3d method set_pane_color(color) and there's another axis3d method set_pane_pos(xys) which is undocumented and does nothing as far as I can tell. Is it in any way possible to position the grid walls manually?
来源：https://stackoverflow.com/questions/25265705/changing-the-position-of-the-grid-walls-in-an-mplot3d-figure