Nope, not topology brush or zspheres. Now my memory is a bit sketchy of how it worked, but the instructor appeared to take a human form, and then used something to actively create new 3d geometry over the surface of that form, a utility belt, vest, and helmet, which were roughly sketched initially but easily refined later. (sort of similar to the way topogun allows the user to work over a model but had nothing to do with modifying topology). not sure about this part, but I think the form’s subtool was then removed, and the newly drawn geometry somehow remained separate and was sent to topogun to be polished up.
Again, it was a lot of training to take in short sessions and he was working quite rapidly. Perhaps he performed a series of unconventional actions to do what I’m describing.
Thanks though for trying to put a finger on it.