In RM Bridge circular elements and radial elements edges, as well as circular construction lines and arched boundaries can be created in Modeler, giving great modeling flexibility.
Initially, users should know that there are new types of construction lines, called Circle and Arc. As shown below, this can be accessed at the CS Window Top Menu by right-clicking at the CL options and selecting the last ones at the right. The Training Example Automeshing at the link below explains this at Sections 3 and 4, respectively for Line-wise or Point-wise boundaries.
communities.bentley.com/.../11-auto-meshing
For circular element edges, check the link below about the element edge radius that allows the user to set a specific variable or value to any element edge.
communities.bentley.com/.../curved-cross-section-elements
As highlighted in the screenshot below, to define additions to curved element edges, the created subdivision point might require a radial line (in red) and a tangential line (in green). The tangent can be defined either by a circle, an arc, or a 90-degree line.
More information can be found at the link below, for stiffeners positioning.