One of the rotations must be turned off in the analyzer or modeler in order to perform the analysis. Feature datums define the kinematic and manufactured dimensions that define the location of the joints relative to the part DRFs. Diagram showing the location of the part DRFs and feature datums. DRFs define the local coordinate systems in each part. Datum selection determines which dimensions contribute to assembly variation.
Datums also influence how parts are fixtured for production and inspection.
The DRFs for the hub and the ring are located at the same coordinates. The modeler will place the DRF labels on top of each other. This makes it necessary to use the 'query select' or 'menu select' function to ensure the correct DRF is selected when defining paths from the kinematic joints back to the part DRFs. 2.5 Kinematic Joints Three kinematic joints are required to model a quarter section of the one-way clutch. Kinematic joint diagram.