Plotting a 3d surface in pylab given the vertices i

Question

I have 6 points which all lie on the surface of a sphere and are the vertices of an octohedron. How can I plor the surface of this octohedron within the sphere on a 3d axes?

I have the following code but it does not do what I was hoping:

from mpl_toolkits.mplot3d import Axes3D
from mpl_toolkits.mplot3d.art3d import Poly3DCollection
import matplotlib.pyplot as plt

Points=[[ 0.17770898,  0.72315927,  0.66742804],
       [-0.65327074, -0.4196453 ,  0.63018661],
       [ 0.65382635,  0.42081934, -0.62882604],
       [-0.17907021, -0.72084723, -0.66956189],
       [-0.73452809,  0.5495376 , -0.39809158],
       [ 0.73451554, -0.55094017,  0.39617148]]

fig=plt.figure()
ax =fig.add_subplot(1, 1, 1, projection='3d', aspect=1)

ax.add_collection3d(Poly3DCollection([Points]))

u = np.linspace(0, np.pi, 30)
v = np.linspace(0, 2 * np.pi, 30)

x = np.outer(np.sin(u), np.sin(v))
y = np.outer(np.sin(u), np.cos(v))
z = np.outer(np.cos(u), np.ones_like(v))

ax.plot_wireframe(x, y, z, alpha=0.3)

plt.show()

Thank you for your help.

Answer 1

To add upon HYRY's answer; a volume is built from a list of several polygonal faces, and each face is in turn built by a list of points. (Each point is thus present several times in the list of lists, if the faces are adjacent). Consider the following snippet, where the points have been labeled:

from mpl_toolkits.mplot3d import Axes3D
from mpl_toolkits.mplot3d.art3d import Poly3DCollection
import matplotlib.pyplot as plt
fig = plt.figure ()
ax = fig.add_subplot (1, 1, 1, projection = '3d', aspect = 1)

# octahedron
A = [ 0.17770898,  0.72315927,  0.66742804]
B = [-0.65327074, -0.4196453 ,  0.63018661]
C = [ 0.65382635,  0.42081934, -0.62882604]
D = [-0.17907021, -0.72084723, -0.66956189]
E = [-0.73452809,  0.5495376 , -0.39809158]
F = [ 0.73451554, -0.55094017,  0.39617148]
OCTO = [[E, A, B],
        [E, B, D],
        [E, D, C],
        [E, C, A],
        [F, A, B],
        [F, B, D],
        [F, D, C],
        [F, C, A],
]
ax.add_collection3d (Poly3DCollection (OCTO))

# sphere
u = np.linspace (0, np.pi, 30)
v = np.linspace (0, 2 * np.pi, 30)
x = np.outer (np.sin (u), np.sin (v))
y = np.outer (np.sin (u), np.cos (v))
z = np.outer (np.cos (u), np.ones_like (v))
ax.plot_wireframe (x, y, z, alpha = 0.3)

plt.show ()