Abstract: In an embodiment, a method of determining loads of columns in building structures based upon both horizontal load factors and vertical load factors in a three-dimensional (3D) model of the building structures on a computer display device comprises: using a computer, obtaining plane definition data that defines a plurality of planes of a building structure, and locations of a plurality of columns that are on, into or above the planes, without load path input data that specifies an explicit load path among the columns, and displaying a 3D geometric representation of the planes and the columns; using the computer and the plane definition data, creating and storing plane tributary region data defining a plurality of tributary regions across the plane that are associated with the columns; determining, using the computer and the plane tributary region data, tributary data defining a tributary for each of the columns based only upon a geometry of the slabs or floors and the locations of the plurality of columns; det