Views are normally created from Dimensions. These Views are then used to define Dimensions in a Fact table where the Dimension appears multiple times. A classic example is the date dimension. To facilitate the creation of the Fact table we create two dimension views to allow the date dimension to be joined to the Fact table twice.
Views can also be created from any other table type. By default, views are displayed as part of the Dimension object group. If Fact table views or other views are being used, then views can be displayed as a separate object type which can be configured from Tools > Options > User Preferences > Look and Feel > General.