This is a post by Natasha Reaves on the Rand 3D Site.
In Creo Parametric 5.0, simplified representations have been enhanced by reducing the multiple predefined representations down to the Automatic Representation. In an Automatic Representation, the minimum required data is retrieved for presenting the assembly as fast as possible and in the most accurate way. Creo determines what data is required based on user actions. For example, only assembly components included in the representation are retrieved in an automatic representation, and all other excluded components remain excluded.