Nate Nate - 3 months ago 65
Python Question

Animate a rotating 3D graph in matplotlib

I have a scatter plot set up and plotted the way I want it, and I want to create an .mp4 video of the figure rotating in space, as if I had used

plt.show()
and dragged the viewpoint around.

This answer is almost exactly what I want, except to save a movie I would have to manually call into FFMpeg with a folder of images. Instead of saving individual frames I'd prefer to use Matplotlib's built in animation support. Code reproduced below:

from mpl_toolkits.mplot3d import Axes3D
ax = Axes3D(fig)
ax.scatter(xx,yy,zz, marker='o', s=20, c="goldenrod", alpha=0.6)
for ii in xrange(0,360,1):
ax.view_init(elev=10., azim=ii)
savefig("movie"%ii+".png")

Answer Source

If you want to learn more about matplotlib animations you should really follow this tutorial. It explains in great length how to create animated plots.

Note: Creating animated plots require ffmpeg or mencoder to be installed.

Here is a version of his first example changed to work with your scatterplot.

# First import everthing you need
import numpy as np
from matplotlib import pyplot as plt
from matplotlib import animation
from mpl_toolkits.mplot3d import Axes3D

# Create some random data, I took this piece from here:
# http://matplotlib.org/mpl_examples/mplot3d/scatter3d_demo.py
def randrange(n, vmin, vmax):
    return (vmax - vmin) * np.random.rand(n) + vmin
n = 100
xx = randrange(n, 23, 32)
yy = randrange(n, 0, 100)
zz = randrange(n, -50, -25)

# Create a figure and a 3D Axes
fig = plt.figure()
ax = Axes3D(fig)

# Create an init function and the animate functions.
# Both are explained in the tutorial. Since we are changing
# the the elevation and azimuth and no objects are really
# changed on the plot we don't have to return anything from
# the init and animate function. (return value is explained
# in the tutorial.
def init():
    ax.scatter(xx, yy, zz, marker='o', s=20, c="goldenrod", alpha=0.6)
    return fig,

def animate(i):
    ax.view_init(elev=10., azim=i)
    return fig,

# Animate
anim = animation.FuncAnimation(fig, animate, init_func=init,
                               frames=360, interval=20, blit=True)
# Save
anim.save('basic_animation.mp4', fps=30, extra_args=['-vcodec', 'libx264'])