Fundamentals > Fundamentals > Relations and Parameters > Terminology Used in Relations and Parameters
Terminology Used in Relations and Parameters
Local parameters—Parameters that are created in the current model. You can edit local parameters in the model.
External parameters—Parameters created outside the current model and used to control some aspects of the model. External parameters cannot be modified in the model. For example, you can add parameters in Notebook mode to define certain part dimensions. When you open that part, these part dimensions are controlled from Notebook mode and are read-only in the part. Likewise, you can create parameters in the PDM system and apply them to the part.
User-defined parameters—Additional information that you can attach to geometry. You can add user-defined parameters to an assembly, part, feature, or entity. For example, you can create a COST parameter for each part in the assembly. Then, you can include the COST parameter in your Bill of Materials to calculate the total cost of the assembly.
System parameters—Parameters defined by the system, for example, the Mass Properties parameter. These parameters are generally read-only. You can use them in relations, but you cannot control their value.
Annotation Element parameters—Parameters defined for an Annotation Element.
Restricted value parameters—Parameters whose values and other properties are defined by an external file.
Relations—Relations are user-defined equations written between symbolic dimensions and parameters. Relations let you capture design intent by defining relationships within features or parts, or among assembly components. You can create relations on different levels: assembly, part, feature, or section.
Section relations—Relations created in Sketcher to control geometry of complex sections. Unless a section dimension changes, section relations generally are regenerated during a part regeneration.
Part relations—Relations added on a part level. During a part regeneration, these relations get resolved before features are regenerated.
Feature relations—Relations added to a selected feature. During a part regeneration, these relations are resolved after part relations, but before the regeneration of the feature to which they apply. You use feature relations to change feature geometry only after part relations are applied and some features have been regenerated.