issue with func in matplotlib.FuncAnimation not updating data

Question

fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
ax.set_xlabel('x')
ax.set_ylabel('y')
ax.set_zlabel('z')
ax.set_xlim([0, 1])
ax.set_ylim([0, 1])
ax.set_zlim([0, 90]) 

x = np.linspace(xL, xR, nx)
z = np.linspace(zL, zR, nz)
X, Z = np.meshgrid(x, z)
r = T[:,5,:,0]

graph = ax.plot_surface(X, Z, r)

def update_graph(q):
    r = T[:,5,:,q]
    graph.set_3d_properties(r)
    return graph

ani = matplotlib.animation.FuncAnimation(fig, update_graph, frames = 11)
plt.show()

I have the code above, T is a 100x100x100x12 matrix, and I want to make an animation showing a surface plot as the 4th axis goes from 0-11. However it seems that the animation portion is not working correctly, and I believe the issue is in my update_graph function that it is not passing back an updated value of r to be used in the plot.

Answer 1

It should be noted that for Poly3DCollection set_3d_properties() is only implemented as the following

def set_3d_properties(self): # Force the collection to initialize the face and edgecolors # just in case it is a scalarmappable with a colormap. self.update_scalarmappable() self._sort_zpos = None self.set_zsort('average') self._facecolors3d = PolyCollection.get_facecolor(self) self._edgecolors3d = PolyCollection.get_edgecolor(self) self._alpha3d = PolyCollection.get_alpha(self) self.stale = True

So it doesn't actually modify the data as it does with other 3d objects (eg Line3D ).

Instead, I would recommend you do something like this

graph = ax.plot_surface(X, Z, r)

def update_graph(q):
    r = T[:,5,:,q]
    plt.cla()
    ax.set_xlim([0, 1])
    ax.set_ylim([0, 1])
    ax.set_zlim([0, 90]) 
    graph = ax.plot_surface(X, Z, r)
    return graph,

Obviously it is a bit tedious to reset all the axis properties on each update but I don't think there is any easier way.

Also note the trailing comma in return graph, - this is necessary when blit=True because FuncAnimation expects an iterable of artists to be returned. However, the return statement is ignored when blit=False .

Here is the result of a simple example using this approach