How to plot a slicing plane with a surface with “matplotlib” in python

Question

I wonder how to create two slicing planes with a surface to two 2d figures.

For example, I created a surface as below:

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

def f(x1, x2):
    return 0.5 * x1 + 0.6 * x2 + 0.2 * x1 * x1 + 0.1 * x1 * x2 + 0.3 * x2 * x2 + 4

x = np.linspace(-3, 3, 100)
y = np.linspace(-3, 3, 100)
xx, yy = np.meshgrid(x,y)
z = f(xx, yy)

# set up the figure
fig = plt.figure()
ax = fig.gca(projection='3d')
ax.set_xlim(-3, 3)
ax.set_ylim(3, -3)
ax.set_xlabel("x")
ax.set_ylabel("y")
ax.set_zlabel("z")

# plot the figure
ax.plot_surface(xx, yy, z, cmap="spring", alpha = 0.7)

# add the x=y line to the ground plane
ax.plot([-3, 3], [-3, 3], color='grey', linewidth=1, linestyle='dashed')

# add the x=-y line to the ground plane
ax.plot([3, -3], [-3, 3], color='grey', linewidth=1, linestyle='dashed')

ax.plot(x, x, f(x, x), color='dodgerblue')
ax.plot(x, -x, f(x, -x), color='dodgerblue')

plt.show()

The surface created by the above code looks like this

After this, I want to add two slicing planes, which are x = y and x = -y planes. And plot the cutting lines of the two planes and the surface to two different 2d figures.

For example, one 2d figure of the cutting line of the surface and the x = y plane would be something like the figure in the red box below, but no surface, just the red curve.

wh41e wh41e · Accepted Answer · 2020-03-04T05:51:27

Actually, just need to plot them in two 2d figures

# slicing figure 1
fig2, ax2 = plt.subplots()
ax2.plot(x, f(x, y, b1, b2, b3, b4, b5, con))
ax2.set_title("x=y plane")
ax2.set_xlim(-3, 3)
ax2.set_ylim(1, 15)

# slicing figure 2
fig3, ax3 = plt.subplots()
ax3.plot(x, f(x, -y, b1, b2, b3, b4, b5, con))
ax3.set_title("x=-y plane")
ax3.set_xlim(-3, 3)
ax3.set_ylim(1, 15)

How to plot a slicing plane with a surface with “matplotlib” in python

1 Answers