Error in display when using animation_control

[fran6w]

The display of a spinning cube shows the bottom and top vertices rotating but they should not

from numpy import array, pi, cos, sin, sqrt

def spinning_cube(n=24):
assert(n % 6 == 0)
sqrt3 = sqrt(3)
r = sqrt(2/3)
x = array([[0, 0, [rcos(a2pi/3+t2pi/n) for a in range(3)], [rcos(a2pi/3+pi/3+t2pi/n) for a in range(3)]] for t in range(n)])
y = array([[0, 0, [rsin(a2pi/3+t2pi/n) for a in range(3)], [rsin(a2pi/3+pi/3+t2pi/n) for a in range(3)]] for t in range(n)])
z = array([0, sqrt3, sqrt3/3, sqrt3/3, sqrt3/3, sqrt32/3, sqrt32/3, sqrt3*2/3])
triangles = [[0, 2, 3], [0, 3, 4], [0, 2, 4],
[1, 5, 6], [1, 6, 7], [1, 5, 7],
[2, 3, 5], [3, 4, 6], [2, 4, 7],
[5, 6, 3], [6, 7, 4], [5, 7, 2]]
return x, y, z, triangles

import ipyvolume as ipv

ipv.figure()
ipv.style.use('minimal')
x, y, z, triangles = spinning_cube(6)
s = ipv.plot_trisurf(x, z, y, triangles=triangles)
ipv.animation_control(s, interval=100)
ipv.show()
ipv.movie('spinning_cube.gif', fps=20, frames=20*4,)

data used

vertex 0 is (0, 0, 0) and vertex 1 is (0, 0, sqrt(3)/2) in all frames

therefore they should not display rotating

x = array([[ 0. , 0. , 0.81649658, -0.40824829, -0.40824829,
0.40824829, -0.81649658, 0.40824829],
[ 0. , 0. , 0.40824829, -0.81649658, 0.40824829,
-0.40824829, -0.40824829, 0.81649658],
[ 0. , 0. , -0.40824829, -0.40824829, 0.81649658,
-0.81649658, 0.40824829, 0.40824829],
[ 0. , 0. , -0.81649658, 0.40824829, 0.40824829,
-0.40824829, 0.81649658, -0.40824829],
[ 0. , 0. , -0.40824829, 0.81649658, -0.40824829,
0.40824829, 0.40824829, -0.81649658],
[ 0. , 0. , 0.40824829, 0.40824829, -0.81649658,
0.81649658, -0.40824829, -0.40824829]])

y = array([[ 0.00000000e+00, 0.00000000e+00, 0.00000000e+00,
7.07106781e-01, -7.07106781e-01, 7.07106781e-01,
9.99919924e-17, -7.07106781e-01],
[ 0.00000000e+00, 0.00000000e+00, 7.07106781e-01,
9.99919924e-17, -7.07106781e-01, 7.07106781e-01,
-7.07106781e-01, -9.25178628e-16],
[ 0.00000000e+00, 0.00000000e+00, 7.07106781e-01,
-7.07106781e-01, -1.99983985e-16, 9.99919924e-17,
-7.07106781e-01, 7.07106781e-01],
[ 0.00000000e+00, 0.00000000e+00, 9.99919924e-17,
-7.07106781e-01, 7.07106781e-01, -7.07106781e-01,
-1.99983985e-16, 7.07106781e-01],
[ 0.00000000e+00, 0.00000000e+00, -7.07106781e-01,
-1.99983985e-16, 7.07106781e-01, -7.07106781e-01,
7.07106781e-01, 2.99975977e-16],
[ 0.00000000e+00, 0.00000000e+00, -7.07106781e-01,
7.07106781e-01, 2.99975977e-16, -1.99983985e-16,
7.07106781e-01, -7.07106781e-01]])

z = array([0. , 1.73205081, 0.57735027, 0.57735027, 0.57735027,
1.15470054, 1.15470054, 1.15470054])