Just to get my thoughts out… My assumption so far is that it follows a similar procedure from ShapeOp*, that attempts to keep vertices still and projects faces onto the closest local planes, and then moving vertices towards these planes. I suppose it seems a little analagous to a VTPI approach to me.

*(Mario Deuss, Anders Holden Deleuran, Sofien Bouaziz, Bailin Deng, Daniel Piker, and Mark Pauly. 2015. ShapeOp - A Robust and Extensible Geometric Modelling Paradigm. Design Modelling Symposium)