Animating a 3D vector

Question

I need to animate both the magnitude and the position of a vector arrow in a 3D figure with matplotlib. As far as I can tell, I cannot animate the position of the vectors with Axes3D.quiver and there is no matplotlib.pyplot.arrow for a 3D figure. Is there a way to do this or do I need to look at other options?

Answer 1

quiver does not have an updating function, but you can easily remove an old quiver and plot a new one in each frame.

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

fig, ax = plt.subplots(subplot_kw=dict(projection="3d"))

def get_arrow(theta):
    x = np.cos(theta)
    y = np.sin(theta)
    z = 0
    u = np.sin(2*theta)
    v = np.sin(3*theta)
    w = np.cos(3*theta)
    return x,y,z,u,v,w

quiver = ax.quiver(*get_arrow(0))

ax.set_xlim(-2, 2)
ax.set_ylim(-2, 2)
ax.set_zlim(-2, 2)

def update(theta):
    global quiver
    quiver.remove()
    quiver = ax.quiver(*get_arrow(theta))

ani = FuncAnimation(fig, update, frames=np.linspace(0,2*np.pi,200), interval=50)
plt.show()