So, they are literally grabbing a sphere that they visualize? If so, please provide some physical detail on that.
Whasssup. First let's clear something here. Visualizing is just a tool until you get the reality.
The reality is you have a spiritual space. In Aikido, or should I say, in that Aikido and my Aikido and maybe many other, it's a fundamental part of training.
You align that space with the physical space. Once again spiritual and physical in unison. That's one aspect of it. But first you have to know the reality of it and then the reality of how to use it in Aikido.
Then the reality of how it applies and to what etc.
I would say first comes body and physical movement of, then energy and how that works complete with yin and yang principles and paths of non-restance etc. and the geometry involved etc and then comes space and the 'mechanics' of. But that's spiritual.