Matplotlib Bar3d Variable Alpha

I'm using matplotlib bar3d with RdBu colormap and wanted to have variable transparency between bars (so smaller bars can be more transparent than taller bars). Here is the code fo

Solution 1:

xpos = np.arange(0,4,1)
ypos = np.arange(0,4,1)
xpos, ypos = np.meshgrid(xpos, ypos)
xpos = xpos.flatten()
ypos = ypos.flatten()
zpos = np.zeros(4*4)
rho = np.random.random((4,4))
dx = 0.5 * np.ones_like(zpos)
dy = dx.copy()
dz = rho.flatten()
nrm=mpl.colors.Normalize(-1,1)
colors=cm.RdBu(nrm(-dz))
alpha = np.linspace(0.2, 0.95, len(xpos), endpoint=True)
fig = plt.figure()
ax = fig.gca(projection='3d')
for i in range(len(xpos)):
    ax.bar3d(xpos[i],ypos[i],zpos[i], dx[i], dy[i], dz[i], alpha=alpha[i], color=colors[i], linewidth=0)
plt.show()