How do other people make custom objects for their projects?

Learn GDL and stop whinging about how good are families. I did use Revit and families are crap. There is nothing better than GDL and you can do anything in GDL and objects are small, fast and fully parametric. Beginning is hard but GDL help is fantastic. If you need help ask GDL user group and somebody will answer. After couple of objects you will never look back to families or Bimobjects. Word of advice - read GDL standards for naming parameters if you want to schedule your own objects. Unfortunately GDL standards are ignored by most of manufacturers and rarely used in Bimobjects.

you can model your own objects with native Arhicad elements such as Walls, Slabs or any other, and then save them as objects by selecting the entire elements and the file/libraries and objects/save object. Or you can create objects through programming using Geometric Description Language (GDL) file/libraries and objects/new object