Product and Manufacturing Information (PMI) – Overview
Product and Manufacturing Information (PMI) consists of non-geometric data, that is attached directly to a 3D CAD model to define geometric dimensioning and tolerancing (GD&T), engineering and manufacturing specifications, dimensions, and text. PMI is part of Model Based Definition (MBD) and together these two elements are a part of a Digital Twin.
Applying PMI to a 3D model can reduce or eliminate the use of 2D drawings and can be used downstream to perform tolerance analytics and coordinate-measuring machine (CMM) inspection.
PMI is a command within NX that gives you the ability to create/attach dimensions and annotations to define the 3D model, and requires model views similar to the views on a drawing. These dimensions and annotations are associative to the 3D geometry, and if it is decided that a 2D drawing is required, then the PMI can be inherited from the 3D model and automatically applied to the drawing views.
We think of MBD and PMI as new technologies and 2D drawings as “old school,” but there are valid uses for a 2D drawing. Given the ability in NX to quickly create 2D drawings with associative dimensions inherited from the 3D PMI… this gives you the best of both worlds.
The image below demonstrates what PMI looks like in a 3D model view, and the next image down demonstrates the inherited PMI in a 2D drawing view: