Revit projects can have named positions. A named position is the placement of a model instance in a Revit project. By default, each Revit project contains at least one named position, called Internal.
If your Revit project contains a unique structure or a site model, it typically has only one named position.
If your Revit project contains several identical buildings, it will have many positions in it.
You want may want several positions of a building to create a campus look. For example:
You might also want several positions for a unique building. In this case, you could import the building into a site model and then move the building around on the site by choosing different positions.
Positions are modifiable in a project. You can delete, rename, and create new positions, and switch between positions.