get an orthogonal view

[Foam-kun]

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 main branch).

My Question

how to use open3d to get an orthogonal view (not a perspective view) of the point cloud, and can save the image.

[BruceLee569]

+1, an orthogonal view is useful to avoid the perspective phenomenon of large near far small, suitable for viewing and aligning the actual size of the object.