Abstract: Interactive feature definition together with automatic feature recognition are applied to recognize machining features. First, machining feature model of a part is built with an extended-hint-based automatic feature recognition algorithm; then local modifications and reinterpretation are made on the established model through interactive feature definition. For redefining features, the user just needs to pick the faces composing the desired feature, then the system automatically invokes feature recognition algorithm to process the remainder faces of machining feature and uses a unified algorithm to calculate corresponding feature parameters. This reduces dramatically the interactive workload. Experiments show that practicability and robustness of feature recognition can be greatly enhanced with the new approach.