Yes, the plaster model was on the inside, and the plaster removed (dissolved?) to leave the freestanding figure.
I found a bit of bumph about the sculptures in general:
" ..after the artistic creation of the sculpture, a hand-made mould consisting of numerous pieces is produced for each individual piece. The mould is destroyed during the production which folows. No two moulds are exactly alike. First, it is created as a cast.It is then worked over, sanded and polished by hand. "
He won the Coburger Glaspreis for modern glass design in Europe, special prize, in 1977.
I'm pretty sure there was no laser involved.
Cathy B...Those dresses are amazing
Will try googling with Christian, hadn't thought of that.