A few years ago I was asked to set a trilliant Sapphire in three
claws so that as much of the stone was as visible as possible while
still ensuring the security of the stone.
I made a silver model to show the customer (who was one of those
people who could not read drawings) Making the model showed me how
difficult it was going to be to position the claws accurately.
A further complication was that the otherwise beautifully cut
sapphire was not absolutely accurately cut.
A friend was learning 'Rhino' and who enjoys a challenge did the CAD
drawing for me, which solved my problem and I had a very happy
customer. an image should be visible on my new Ganoksin Gallery If
however you want a bezel setting you should be able to see my
Stonesetting notes on my blog on Ganoksin: 'On Your Metal'.
There is a diagram and instruction sheet for making bezel settings