Parts and Documents
The figure above illustrates one of the most fundamental concepts of the VEC – the separation of a part and its description. In the VEC a part (PartVersion) does not contain any information about the part, except its PDM Information (PartNumber, PartVersion…). All the information about the technical properties of a part is expressed by a subclass of PartOrUsageRelatedSpecifications (e.g. a WireSpecification). The specifications itsselfes are contained in a DocumentVersion.
This approach enables the VEC to address two scenarios properly:
- The description of a part is changed, but the part itself is not changed (rereleased). This can happen for example if the actual technical properties of the part stay the same, but the description is extended or corrected.
- A document and the contained specifications are describing more than one part (e.g. a drawing for a certain class of terminals). In this case it can happen that the document and the specifications are changed, but not all of the described parts have to be changed (rereleased).
The example illustrates the use of UsageNodes. A UsageNode represents a position in an abstract vehicle. For example the Head Light Left. UsageNodes belong to the master data and they are defined on some company wide level. They can be used to enforce consistent naming over different projects and different development streams (e.g. between geometry and electrologic).
A UsageNode can be subdivided into more detailed UsageNodes. For example the Head Light can be split up into Main Beam, Low Beam and Direction Indicator.