Answer:
If there are different cross-section types at the start and end of a tapered member that do not have the same number of stress points, RFEM/RSTAB draws the first half with one cross-section and the second half with the other cross-section.
Furthermore, it is necessary to ensure that the stress points with the same numbers are opposite each other.
A "continuous" taper is drawn if the same cross-section type (cross-section row) is present at both ends and the stress points are opposite each other.
For example, you could copy the cross-section with the smaller height and then adjust the height and/or width of the second cross-section.
Note
The easiest way to do this is to model both cross-sections as welded sections or parameterized cross-sections.
