Pardon the lapse, TTRAG and a raising demanded most of my time the past few.

Interestingly, the first polygon I worked on was a ill-fated attempt to replicate a twenty sided Globe with and under the direction of a friend of Ken’s, Paul Russell, the man I had the good fortune to learn scribe from many years ago. Ironically I picked up a long out of print tome on the Theatre in an antiquarian bookshop just yesterday

Mark –

Brace both the radial bents and the inner circumferential ring liberally, the main ring, to the extent that your window and door schedule allows. This is also where you can both negate and redirect thrust through strut/s to the inner ring where it is best resolved

Common purlins are an excellent step towards redirecting and concentrating thrust to the principals/hips.

Michal –

I’m afraid we will have to agree to disagree on the tension ring issue, however I must qualify that with a big ‘ole “in my opinion”

IMO good timberframe design demands the elimination of all possible tension joinery on the drawing board, I choose to do this, in that there are few joints available to us which deal with tension well.

The best case for a polygonal ring, are daps with material projected on beyond the vertices for ample relish. Mark is free to do this even on the main ring, simply by choosing to deal with the work necessary to cut and fit the SB enclosure around the relish, he is freer still to do this on the inner rings.

When we have the freedom to direct thrust away from one joint and in the redirecting now impart it not as thrust, but largely as a dead load to a point in the frame better able to deal with it, why not take advantage of that freedom ?