Thanks for the link to the tank track post Michael, but im baffled to see how it works! Surely the straight line distance around the curved bit will be shorter than the distance between the points on the straight bit as I think MOI (correctly) calculates the length of the curve not the shortest distance between points. I was wondering if it was possible for MOI to have an extra method that uses the straight line method for its calculation? Im thinking it would be useful in curved planar glass wall construction where the glass is usually made up of consistent sized glass modules, or possibly more complex shapes like the Swiss Re building in London - that was where the quick triangle experiment came from. Im thinking the actual swiss re shaped glazing pattern would be pretty hard to achieve with moi at the moment but a more basic purely horizontal curving should be possible. This way it would be easier to work with a single unit (structure and glazing) that could be then instanced (when the time comes) along the curve, rather than having each piece slightly different. Of course how these join propperly would need to be carefully managed but by and large it would be a big time saver.

Cheers