best bet is still a custom profile with 4 triangular fills. The profile manager no longer "heals" fills automatically in section the way it did 6 years ago, so you can use a single fill (building material). You can also set a range of horizontal/vertical stretch parameters, so you only need a single profile to cover all square cut timber for beams/joists/etc.
BIM solutions and trouble shooting (self proclaimed) expert. Using Archicad 26 5002 US on Mac OS 11.5.2