How to flip y axis in a bar3d() plot?

Question

I use bar3d() to plot a 3D barchart, and I'd like to flip the y axis. I've tried to use invert_yaxis(), but it seems effectless. I've also tried manually reverse the values in the list with [::-1], but it didn't help either. It keeps displaying the 3D barchart in the very same way.

Any idea how can I flip the y axis?

Here's an example how it's not working for me (not even with 3D line plots):

from matplotlib.pyplot import *
from mpl_toolkits.mplot3d.axes3d import Axes3D

fig1 = figure(1)

ax11 = subplot(2, 2, 1, projection='3d')
ax11.plot([1, 2, 3, 4], [1, 2, 3, 4])

ax12 = subplot(2, 2, 2, projection='3d')
ax12.invert_xaxis()
ax12.plot([1, 2, 3, 4], [1, 2, 3, 4])

ax21 = subplot(2, 2, 3)
ax21.plot([1, 2, 3, 4])

ax22 = subplot(2, 2, 4)
ax22.invert_xaxis()
ax22.plot([1, 2, 3, 4])

show()

And the plot looks like this: http://we.tl/cqSsecVy6P

Thanks, Daniel

Answer 1

If I understand the question correctly I think the problem is that matplotlib rotates the 3D plot. To remedy this just set the initial viewing angle using ax.view_init(elev, azim). Taking the matplotlib hist3d demo then we just have

from mpl_toolkits.mplot3d import Axes3D
import matplotlib.pyplot as plt
import numpy as np

fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
x, y = np.random.rand(2, 100) * 4
hist, xedges, yedges = np.histogram2d(x, y, bins=4)

elements = (len(xedges) - 1) * (len(yedges) - 1)
xpos, ypos = np.meshgrid(xedges[:-1]+0.25, yedges[:-1]+0.25)

xpos = xpos.flatten()
ypos = ypos.flatten()
zpos = np.zeros(elements)
dx = 0.5 * np.ones_like(zpos)
dy = dx.copy()
dz = hist.flatten()

ypos_inv = ypos
ax.bar3d(xpos, ypos, zpos, dx, dy, dz, color='b', zsort='average')
ax.view_init(ax.elev, ax.azim+90)
plt.show()

Here I have rotated the axis by 90 degrees which flips one of the axis but not the other.