In recent years, various researchers have come up with different ways and means to integrate CAD and CAM. Automatic feature recognition (AFR) from a CAD solid model for down stream applications like process planning and NC program, greatly contribute to the level of integration. When generating G&M codes from CAD DXF file, it leads to the loss of geometric information and the user is to edit and fills the details of the lost data. STEP is an international standard for geometric and non geometric data transfer between CAD, CAE and CAM and it replaces the IGES and DXF. For that reason this paper proposes an automatic feature recognition methodology to develop a feature recognition system using STEP file.

The proposed methodology is developed for 3D prismatic parts that are modeled any CAD software having STEP output file format. A JAVA program is used to implement the geometric data extraction algorithm, which has been developed for extracting the geometric information from the STEP file. A feature recognition algorithm is used to recognize the different features of the part such as slot, pocket etc based on geometric reasoning approach by taking B-rep data base as input. The authors present an example to demonstrate the application of the proposed methodology.