I was desperate to fix this so I installed windows 8.1 on
a secondary storage drive to see if SH3 anti aliasing
worked on the 8.1 system and it does!
.
No idea why I couldnt force anti aliasing in windows 10.
I tried everything suggested here and elsewhere.
Anyway, happy to play SH3 once again in its full graphical
glory ....wide screen and anti aliased to the hilt