matplotlib - Python 3d Pyramid

Question

I'm new to 3d plotting. I just want to build a pyramid out of 5 Points and cut a plane through it. My problem is I don't know how to fill the sides.

points = np.array([[-1, -1, -1],
                   [1, -1, -1 ],
                    [1, 1, -1],
                   [-1, 1, -1],
                   [0, 0 , 1]])
fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
r = [-1,1]

X, Y = np.meshgrid(r, r)

ax.plot_surface(X,Y,-1, alpha=0.5)
ax.plot_surface(X,Y,0.5, alpha=0.5,  facecolors='r')


ax.scatter3D(points[:, 0], points[:, 1], points[:, 2])
ax.set_xlabel('X')
ax.set_ylabel('Y')
ax.set_zlabel('Z')
plt.show()

Any help is appreciated.

Answer 1

You have to use polygons:

from matplotlib import pyplot as plt
from mpl_toolkits.mplot3d.art3d import Poly3DCollection, Line3DCollection
import numpy as np

fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')

# vertices of a pyramid
v = np.array([[-1, -1, -1], [1, -1, -1], [1, 1, -1],  [-1, 1, -1], [0, 0, 1]])
ax.scatter3D(v[:, 0], v[:, 1], v[:, 2])

# generate list of sides' polygons of our pyramid
verts = [ [v[0],v[1],v[4]], [v[0],v[3],v[4]],
 [v[2],v[1],v[4]], [v[2],v[3],v[4]], [v[0],v[1],v[2],v[3]]]

# plot sides
ax.add_collection3d(Poly3DCollection(verts, 
 facecolors='cyan', linewidths=1, edgecolors='r', alpha=.25))

plt.show()