Answer:
When checking the deformation value, for example, as a result of the deformation analysis in STEEL EC3, it is necessary to subtract nodal deformations from the total deformation shown in RSTAB (see Image 01): the deformation value in the center of the member represents the total deformation of the component (the deformation of nodes plus the deformation of the component).
If the deformation is set as relative to the "undeformed system" in the Details of the serviceability limit state design in the add-on module (see Image 02), the maximum deformation including nodal deformations (the deformation value displayed in RFEM/RSTAB) is used.
