Add multiple (>1000) geometries to O3DVisualizer with update through time

**Is your feature request related to a problem? Please describe.**
I am using open3D to make visualisation engine for particle trajectories. For each particle I must render a mesh, typically a sphere. Making the initial scene is quite simple but when I wish to run the trajectory through time I am unsure of the best way to go. Typically I think of one of the follow:

1. Apply a transformation to all spheres. This is fine but very slow, particularly if the loop is in Python.
2. Make all the scenes at the initialisation stage and just display a new scene. I don't know how this is possible in Open3D.
3. Re-draw the spheres in their new positions in the same visualiser. This I think could be the best way, however, I have to add each sphere one at a time using the vis.add_geometry method. If I could add all the sphere (or at least do it vectorized) this would probably be the best approach.

I am just looking for some ideas about the best way to do this. Typically I want to visualise >1000 particles and so performance is fairly important. Any ideas would be greatly appreciated.