Is the function called by render_to_depth_image running on a separate thread?

[geppi]

I'm still a little puzzled why you have to use open3d.visualization.gui.Application.post_to_main_thread in the mouse_and_point_coord.py example.

Is my assumption right that the function called by open3d.visualization.rendering.Scene.render_to_depth_image is executed on a thread separate from the main-thread?

This is the only explanation I could come up with to explain why you have to use post_to_main_thread when calling gui methods from within this callable.

If this is the case it should be highlighted in the documentation because as far as I understand most gui widget callbacks are executed on the main-thread, right? Or are they also executed in a separate thread which I cannot imagine because then you would also need to use post_to_main_thread to do anything influencing the gui from within the callbacks.

It also seems open3d.visualization.rendering.Scene.render_to_image is a similar case, right?