After you’ve created element definitions for a curtain wall style, you can assign those definitions to each of the curtain wall element types: divisions, cell infills, frames, and mullions.
By default, one definition is assigned to all elements of a particular type. However, you can assign definitions to individual elements as well. For example, all cells in the grid are assigned the default infill. You can, however, create a new cell assignment, select a different infill, and then specify the cells to use that infill.
Assignment list