Surface and 3d contour in matplotlib

30,449

Apparently it is a bug, if you try this

import numpy as np
from mpl_toolkits.mplot3d import axes3d
import matplotlib.pyplot as plt

fig = plt.figure()
ax = fig.add_subplot(111, projection="3d")
X, Y = np.mgrid[-1:1:30j, -1:1:30j]
Z = np.sin(np.pi*X)*np.sin(np.pi*Y)


ax.plot_surface(X, Y, Z, cmap="autumn_r", lw=0, rstride=1, cstride=1)
ax.contour(X, Y, Z+1, 10, lw=3, colors="k", linestyles="solid")
plt.show()

And rotate around, you will see the contour lines disappearing when they shouldn't

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nicoguaro
Author by

nicoguaro

I work in Computational Mechanics.

Updated on July 15, 2022

Comments

  • nicoguaro
    nicoguaro almost 2 years

    I would like to plot a surface with a colormap, wireframe and contours using matplotlib. Something like this:

    enter image description here

    Notice that I am not asking about the contours that lie in the plane parallel to xy but the ones that are 3D and white in the image.

    If I go the naïve way and plot all these things I cannot see the contours (see code and image below).

    import numpy as np
    from mpl_toolkits.mplot3d import axes3d
    import matplotlib.pyplot as plt
    
    fig = plt.figure()
    ax = fig.add_subplot(111, projection="3d")
    X, Y = np.mgrid[-1:1:30j, -1:1:30j]
    Z = np.sin(np.pi*X)*np.sin(np.pi*Y)
    ax.plot_surface(X, Y, Z, cmap="autumn_r", lw=0.5, rstride=1, cstride=1)
    ax.contour(X, Y, Z, 10, lw=3, cmap="autumn_r", linestyles="solid", offset=-1)
    ax.contour(X, Y, Z, 10, lw=3, colors="k", linestyles="solid")
    plt.show()
    

    enter image description here

    If a add transparency to the surface facets then I can see the contours, but it looks really cluttered (see code and image below)

    import numpy as np
    from mpl_toolkits.mplot3d import axes3d
    import matplotlib.pyplot as plt
    
    fig = plt.figure()
    ax = fig.add_subplot(111, projection="3d")
    X, Y = np.mgrid[-1:1:30j, -1:1:30j]
    Z = np.sin(np.pi*X)*np.sin(np.pi*Y)
    ax.plot_surface(X, Y, Z, cmap="autumn_r", lw=0.5, rstride=1, cstride=1, alpha=0.5)
    ax.contour(X, Y, Z, 10, lw=3, cmap="autumn_r", linestyles="solid", offset=-1)
    ax.contour(X, Y, Z, 10, lw=3, colors="k", linestyles="solid")
    plt.show()
    

    enter image description here

    Question: Is there a way to obtain this result in matplotlib? The shading is not necessary, though.