You can create curved beams from primary and secondary members in a
structure system. Curved members behave the same way as linear members where you can add
secondary members between them.
If you select a 3D curve or spline as a reference, the member can only pierce
through the center of the profile. Also, in some scenarios, you cannot sweep members
with 2D or 3D splines because of their curvature and radius.
You can also merge multiple members that are tangent to each other into a
single member with the Merge Tangent Members
option and add secondary members between merged members.