jupyter widget problem: pythreejs

I try a simple example of pyvista in a jupyter notebook, but there is no rendering. Instead, I get the following error message in the terminal: [W 10:09:59.253 NotebookApp] 404 GET /static/ipygany.js?v=20210929100904 (::1) 1.600000ms referer=http://localhost:8833/notebooks/create-poly.ipynb

---

import numpy as np
import pyvista as pv

# mesh points
vertices = np.array([[0, 0, 0],
                     [1, 0, 0],
                     [1, 1, 0],
                     [0, 1, 0],
                     [0.5, 0.5, -1]])

# mesh faces
faces = np.hstack([[4, 0, 1, 2, 3],  # square
                   [3, 0, 1, 4],     # triangle
                   [3, 1, 2, 4]])    # triangle

surf = pv.PolyData(vertices, faces)

# plot each face with a different color
surf.plot(scalars=np.arange(3), cpos=[-1, 1, 0.5])

---

System Information: Please run the following code wherever you are experiencing the bug and paste the output below. This report helps us track down bugs and it is critical to addressing your bug:

--------------------------------------------------------------------------------
  Date: Wed Sep 29 10:13:44 2021 MDT

                OS : Darwin
            CPU(s) : 16
           Machine : x86_64
      Architecture : 64bit
       Environment : Jupyter
        GPU Vendor : ATI Technologies Inc.
      GPU Renderer : AMD Radeon Pro 5500M OpenGL Engine
       GPU Version : 4.1 ATI-3.10.22

  Python 3.9.2 (default, Feb 19 2021, 17:09:53)  [Clang 12.0.0
  (clang-1200.0.32.29)]

           pyvista : 0.32.1
               vtk : 9.0.3
             numpy : 1.20.1
           imageio : 2.9.0
           appdirs : 1.4.4
            scooby : 0.5.7
            meshio : 4.4.6
        matplotlib : 3.3.4
           IPython : 7.28.0
        ipyvtklink : 0.2.1
             scipy : 1.6.1

[akaszynski]

by the way, opacity and plotting polydata that has only points and no triangles also seems buggy on my end using pythreejs.

Jupyterlab plotting using pythreejs is in super-beta, so it’s no surprise that it’s broken. If you find specific bugs, could you please post a minimum working example here so we can patch it?

[dstansby]

The reason for this is we’ve disabled “double side plotting” within pythreejs. I can enable this, but it’s generally not advisable as it can cause plotting artifacts for complex meshes. Probably what we need to add is options for pythreejs.

Is there a way to enable it from the user end? I’ve just spend a while getting quite confused about only one side of the mesh being rendered by pythreejs, when both sides are rendered in a ‘normal’ pyvista plot.