Dont use the fillet - just make your own points along the needed 3D-curve. Its segmented anyway in Archicad.. Archicad is not the real choise to use for interior design - its for bigger things like houses. Such little things You want to design - its not impossible in AC but its not the best tool for that. Rhino, Blender are much better in this topic.
AC5.5-AC26EduAut, PC-Win10, MacbookAirM1, MacbookM1Max, Win-I7+Nvidia