Standard for Exchange of Product Model Data (STEP) is a Standard associated with representation of product data model to enable data communication between different Computer-aided Design (CAD), Computer-aided Manufacturing (CAM) and other engineering systems without any ambiguities and any possible data losses. The development of Open Architecture (PC-based) Numerical Control (OAPC-NC) Interpolator has enhanced the possibilities of data communication between the systems. A tool path data interface to OAPC-NC interpolator is proposed and developed; and a hierarchical-based algorithm is used to extract the tool path data from STEP-NC tool path file of a product model. The generated output of the interpolated data is computer simulated for 3D straight-line path to verify the validity of the interpolator input generated by the proposed interface.