Answer:
In RFEM 6 and RSTAB 9, you have the option to assign different cross-sections at the start and end of a member, see the following image.
You can define different cross-sections at the member start and member end. The calculation options for both ends of the member need to be identical. Dialog Box | Editing Cross-Section | Main | Options:
If there are different options defined at the member ends, this error messages appear.
Example: The "Deactivate shear stiffness" option is defined differently at both member ends:
Example: The "Thin-walled model" option is defined differently for a steel beam:
This leads to the following error message:
For correct modeling, it is necessary to define the same options on both member ends.
