Normally we calculate Circular Arc Truss from outer diameter ,calculate by meters, price is the unit price on the perimeter,In the process of factory production, generally every segment of the arc between 2 ~ 3.5 m, each section of the arc size, length is the same and also Has a tube of circular section is in accordance with the terms of price, generally every period of arc length between 2 ~ 3.5 m, point of view is commonly 180, 90, 60, 45, 30, 22.5 degrees to points. 6.5 M diameter circle, for example, the perimeter is: 6.5 * 3.14 = 3.14 M each arc length control in 3.5 M or so can be divided into 6 segments, is at 60 degrees to each.

The Circular truss system may devided into three parts, and it can calculate diameter for 2 or 3 meters