user423805 - 4 months ago 11
Python Question

# Plotting A Hyperboloid

Teacher in class gave this formula

``````w = x**2 + y**2 - z**2
``````

and showed its 3d graphic in class seen below. How do I plot this using Matplotlib (minus the intersecting plane)? I guess first a specific value for w needs to be selected, for example 10, otherwise 3d plotting would not be possible. Then should I convert to polar coordinates because of the z**2 in the formula? I tried this and failed. Any help would be appreciated. Also, does this shape have a name?

Got it. Found some good stuff here, and following the formulas presented, I have the Python code below.

http://msenux.redwoods.edu/Math4Textbook/Plotting/ParametricSurfaces.pdf

``````from __future__ import division

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

fig = plt.figure(figsize=plt.figaspect(1))  # Square figure
ax = fig.add_subplot(111, projection='3d')

r=1;
u=np.linspace(-2,2,200);
v=np.linspace(0,2*np.pi,60);
[u,v]=np.meshgrid(u,v);

a = 1
b = 1
c = 1

x = a*np.cosh(u)*np.cos(v)
y = b*np.cosh(u)*np.sin(v)
z = c*np.sinh(u)

ax.plot_surface(x, y, z,  rstride=4, cstride=4, color='b')

plt.show()
``````
Source (Stackoverflow)