A design option set is a collection of possible solutions for a particular design problem. Each design option set contains one primary option and one or more secondary options.
For example, you can create one design option set to show different designs for the entry of a building. You can create another design option set for alternative roof configurations. Each design option set contains one primary option and one or more secondary options.
To create a design option set
By default, Revit names the new set Option Set 1 and creates a primary option in the set.
Now you can edit the primary design option to add elements to it, and create secondary options for the design option set. See Edit a design option and Add one or more secondary design options.
By default, project views show the main model with the primary option for each set. If you want project views to show the main model only, with no design options, see Viewing the Main Model Without Design Options. To see a list of design option sets and design options defined for a project, click the Design Options drop-down list on the status bar.