A door/window assembly consists of one or more grids, which are the framework for placing design elements in the door/window assembly. The highest-level grid is the primary grid, which is also the outside edge of the door/window assembly.
Each grid in a door/window assembly has one division assignment that determines whether the grid is divided horizontally or vertically. The division also determines the number of cells, their size, and their placement.
Within the primary grid, you can define multiple levels of grids. These grids within the primary grid are called nested grids. Each subdivision of a grid is called a cell.
You can create a variety of division definitions under different names and then assign different divisions to each grid in your door/window assembly. Although you can create multiple definitions, there can be only one division assignment per grid. You create division definitions for a specific door/window assembly style and those definitions can be assigned only to grids in door/window assemblies of that style.