Armatures, Grids, and Grid Systems
Armatures, Grids, and Grid Systems are three ways one can structure a design. They assist a designer in creating a hierarchy. Armatures is the more organic approach out of these. As grids are based more on mathematics, the armatures are based on intuition. Although deliberate, it has more of a random feel to its placement. The text compares this approach to the art of drawing, as the designer factors principles like proportion, scale, and harmony, and relies on being compositionally sound.
Grids, like armatures, also bind elements with the same visual rules, but there is also a structural aspect involved. There is a skeletal structure set behind the design. A form that dictates the placement of each element.
Grid systems are a more advance approach than a basic grid, since the system spans deeper than just one document. The text refers to it as a calculated program, a complex mathematic plan. Each element adheres to this organizational map. This grid can span across many pages of a design, for instance a design portfolio.