New windows appeared really slow when using draw_geometry() function (Python)

[CocoaPebble]

Checklist

• [X] I have searched for similar issues.
• [X] For Python issues, I have tested with the latest development wheel.
• [X] I have checked the release documentation and the latest documentation (for master branch).

My Question

Hi there,

I was trying to run the draw_geometry() method with demo files and my own data, but the new windows take really long time (about 30 seconds) to display and show a simple point cloud. I saw a similar question at https://github.com/isl-org/Open3D/issues/2706, while someone responded that the bug was fixed in 0.11.2. However, I am currently using the new version 0.15.1 but still facing this problem.

• Operating system: Windows 11 Home
• Python version: 3.8.13
• Open3D version: 0.15.1
• Is this remote workstation?: no
• How did you install Open3D?: pip

[qscgy]

I am also having this issue, and it also happens when calling gui.Application.instance.initialize(). Sometimes the window opens within a second or so, but most times it takes 30-50 seconds. There does not appear to be any pattern with what causes the issue, and I got the same intermittent slowness using Python VTK to load the same object (a .obj file).

• Operating system: Ubuntu 20.04 LTS
• Python version: 3.9.12 (conda)
• Open3D version: 0.15.1
• Is this remote workstation: no
• How did you install open3d? pip, in a Conda environment This issue also occurs on the same system using open3d 0.13.0 and python 3.8.

[AlexanderRitter02]

For me it takes 41 seconds to open, just with the simple Open3D knot mesh (run it 2 times so it downloads the mesh first):

import open3d as o3d

knot_mesh = o3d.data.KnotMesh()
mesh = o3d.io.read_triangle_mesh(knot_mesh.path)
mesh.compute_vertex_normals()
o3d.visualization.draw_geometries([mesh])

I know that the issue also occurs with the newest Open3D (0.18) from a previous installation. However currently tested with the following versions, since I downgraded Open3D for unrelated reasons:

• Operating system: Windows 22H2 64-bit
• Python version: 3.10.13 (conda)
• Open3D version: 0.16.0 for this test
• Is this remote workstation: no
• How did you install open3d? pip, in a Conda environment