Answer:
For irregular member structures, the load generators "From Area Loads on Members via Plane" or "via Cells" can be helpful. However, both functions assume that the nodes of the members are located in one plane. In the settings of the load generators, it is possible to increase tolerances for the nodes also to detect the nodes lying outside the plane (see Image 01). In combination with the "virtual lines", it is possible to load even more complex structures.