Well it's 3DSOLID - it is just with flipped faces and it acts opposite than real 3DSOLID when modelling operations applied... This sort of thing IMO isn't too helpful when dealing in 3D SPACE - it can just bring problems... Antimatter is empty DWG... You have nothing and when you subtract nothing from nothing or union nothing with nothing or intersect - you should get nothing and not something... If this strange things are improvement to CAD then I am disappointed... When modelling is an issue, there are more important things to be solved than playing with those things... For example, UNION, SUBTRACT and INTERSECT will error when dealing with close to overlapping 3DSOLIDS - inconsistent face-face relationship - Modelling error... :
http://www.theswamp.org/index.php?topic=53736.0Or there is also unsolved non uniform scaling of 3DSOLIDS - LISP can only be some sort of support, but not solution - look here :
http://www.theswamp.org/index.php?topic=53008.15Anyway for purpose of experimentation this is acceptable, but for practice, work and real appliance this thing can only bring chaos...
Nice that you are well and you posted. Thanks to that and happy New forthcoming 2019 Year to you and your family...
Best wishes to all, M.R.