Parametric is a term used to describe a dimension’s ability to change the shape of model geometry as soon as the dimension value is modified. Parametric modelling uses the computer to design objects or systems that model component attributes with real world behaviour.
Feature-based is a term used to describe the various components of a model. For example, a part can consists of various types of features such as holes, grooves, fillets, and chamfers. A ‘feature’ is the basic unit of a parametric solid model.
One of the most important features of parametric modelling is that attributes that are interlinked automatically change their features. In other words, parametric modelling allows the designer to define entire classes of shapes, not just specific instances.
Organizations often turn to parametric when making families of products that include slight variations on a core design, because the designer will need to create design intent between dimensions, parts and assemblies. This supports designs that will need to be modified or iterated on a regular basis. It also creates models with individual features that can be modified or changed that are captured in a ‘model tree.’