Plotly plot_trisurf isn't working with arange arrays

Question

I've basically just copied the example code found on the Matplotlib website, but I replaced their radii and angles with simple arange arrays.

I've tried different array functions and I can't seem to figure out anything.

from mpl_toolkits.mplot3d import Axes3D  

import matplotlib.pyplot as plt
import numpy as np
from Equation import Expression


x = np.arange(0,100,0.01)
y = np.arange(0,100,0.01)
x2 = np.append(0,x.flatten())
y2 = np.append(0,y.flatten())
z = x2 + y2
print(z)
fig = plt.figure()
ax = fig.gca(projection='3d')
ax.plot_trisurf(x, y, z, linewidth=0.2, antialiased=True)
plt.show()

I'm just trying to make a graph of z = x + y but I'm getting a confusing error.

"RuntimeError: Error in qhull Delaunay triangulation calculation: singular input data (exitcode=2); use python verbose option (-v) to see original qhull error."

Edit: I've also tried it without calling flatten() but I get the same result though.

Answer 1

The error you are getting is because your z is not a surface but a line. You need to use at least 3 points that would define a plane. One option could be to use np.meshgrid to create your surface for plotting and then flatten everything to insert into the function. Try going back to some example code here. Note you may also want to change your resolution depending on the detail of your surface.

from mpl_toolkits.mplot3d import Axes3D  

import matplotlib.pyplot as plt
import numpy as np


x = np.arange(0,100,1)
y = np.arange(0,100,1)
x2 = np.append(0,x.flatten())
y2 = np.append(0,y.flatten())

x2,y2 = np.meshgrid(x2,y2) #This is what you were missing

z = x2 + y2

fig = plt.figure(figsize=(12,12))
ax = fig.gca(projection='3d')
ax.plot_trisurf(x2.flatten(), y2.flatten(), z.flatten(), linewidth=0.2, antialiased=True) #flatten all the arrays here


plt.show()