What Archicad version are you using?
I am assuming that this is the new handrail tool?
If it is then check the railing connections - but it is a little odd they are showing in plan but not 3D.
I am wondering if it could be a missing library part - does you Library Manager report any problems with missing objects?
Barry.
One of the forum moderators.
Versions 6.5 to 27
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11