Curved trussing: arc sections, arches, full circles, ellipses, etc.
For Triangular Truss note the apex orientation: "Apex up/down" is commonly used for situations where equipment is being hung; "apex in" is commonly used for screens, and "apex out" is used often for arches. Of course there is nothing to prevent any of them being used in other situations - if necessary please call for advice.
Quantity refers to the metres of external arc length, for pricing purposes. We will discuss with you and provide in the most suitable way (generally for complete circles it is the least number of sections divisible by four, thereby allowing the circle to be split into quarters, etc).