# Why plotly doesn't draw horizontal trisurf?

Hi all,

Using the below code, simply I can draw a surface that I need.

import plotly.figure_factory as ff

import numpy as np
from scipy.spatial import Delaunay

u = np.linspace(0, np.pi, 24)
v = np.linspace(-1, 0, 8)

u,v = np.meshgrid(u,v)

u = u.flatten()
v = v.flatten()

z = np.sin(u/2)#*0+1

points2D = np.vstack([u,v]).T
tri = Delaunay(points2D)
simplices = tri.simplices

fig = ff.create_trisurf(x=u, y=v, z=z,
colormap="Portland",
simplices=simplices,
title="Mobius Band")
fig.show()



and the result is correct as I need:

But when I make the surface horizontal, I encounter with error?

import plotly.figure_factory as ff

import numpy as np
from scipy.spatial import Delaunay

u = np.linspace(0, np.pi, 24)
v = np.linspace(-1, 0, 8)

u,v = np.meshgrid(u,v)

u = u.flatten()
v = v.flatten()

z = np.sin(u/2)*0+1

points2D = np.vstack([u,v]).T
tri = Delaunay(points2D)
simplices = tri.simplices

fig = ff.create_trisurf(x=u, y=v, z=z,
colormap="Portland",
simplices=simplices,
title="Mobius Band")
fig.show()


What is the problem???