This research takes a feature data model, i.e. STEP-NC as input and determinesinteractions among the features in the model. The feature interaction data arethen appended to the original data model for subsequent uses such as processplanning. The method is generic by defining and utilising a set of interactionentities such as removal volumes, common volumes, connection face and bridgefaces. This feature interaction data model is developed using the EXPRESSlanguage, making it compatible with the STEP-NC data model. The interactiondata are presented in both 3D and feature interaction graph (FIG) format in adeveloped software system assisted by the Open CASCADE solid modelling kernel.