Answer:
Generally, line loads are assigned to lines within the program.
In principle, line loads are only suitable for lines that belong to a surface. This means that the line either represents the boundary line of the surface or it must be integrated into the surface. Applying loads to a line that is assigned to both a member and a surface can be done without problems.
If no surface is available and you want to apply a distributed load to a member, you have to use the member load type.
