RM Bridge can create curved circular cross-section elements with the use of additional definitions for the Rounding of elements' edges. As shown below, this will apply one constant radius value to one of the sides of the element.

   

For accuracy or when another element should intersect the rounded side of the element, it is usually necessary to subdivide the element. To add elements to the curve users will have to subdivide them with points. As the FEM elements use one point for each element node to create an element-to-element connection, the user needs to add a perpendicular and a tangent CL – Construction Line. The element's endpoints are then assigned to those intersections. What is different for curved sections is that, because of the curvature, there is no line in the development of the element faces. Therefore, usually in these cases, the best way to do it is to use the element radius and central point to define both the perpendicular line and the tangent lines at the intersection of exact points. A good reference for this is the catalog cross-section Circle-hollow, as shown above: the refinement of the cross-section is dependable on how many elements it is made of. To create exact subdivision points the additional angle is established, in this case, the 45 degrees, as well as the external and internal tangent parallel lines for the points to be used.