If you installed open3d in python’s virtual env, then activate conda environment first.

then,

open3d \\
example   View or run an Open3D example. Example usage: 
          open3d example --list                                  # List examples
          open3d example --list geometry                         # List examples in geometry
          open3d example geometry/point_cloud_convex_hull        # Run an example
          open3d example --show geometry/point_cloud_convex_hull # Show source code of an example
        
draw      Load and visualize a 3D model. Example usage:
          open3d draw                                            # Start a blank Open3D viewer
          open3d draw path/to/model_file                         # Visualize a 3D model file

interface when you type

interface when you type open3d draw

Discuss on voxel size.

https://github.com/isl-org/Open3D/issues/1273