Variant Description ModelThis model type is used to describe the set of features of a single productin the product line. Taking the Input Models of a Configuration Space andmaking choices where there is variability in the Input Models creates thesemodels

Family ModelThis model type is used to describe how the products in a product line willbe assembled or generated from pre-specified components. Each compo-nent in a Family Model represents one or more functional elements of theproducts in the product line, for example software (in the form of classes,objects, functions or variables) or documentation. Family models are de-scribed in more detail in Section 5.4, “Family Models”.

Feature ModelThis model type is used to describe the products of a product line in termsof the features that are common to those products and the features that varybetween those products. Each feature in a Feature Model represents a prop-erty of a product that will be visible to the user of that product. These mod-els also specify relationships between features, for example, choices be-tween alternative features. Feature Models are described in more detail inSection 5.3, “Feature Models”.

In reality, this linear flow is rarely found in practice.Product Lines usually evolve continuously, even after the first product variants have been defined and deliveredto customers.