A method and appertaining system are provided for automatically modeling a hearing aid sheet design. A 3D geometric description of an undetailed shell model is received, and its features and associated descriptors are automatically extracted. These features are classified, and a database of existing shells and features is queried to determine if a stored shell model matches the received shell model or if stored features match one or more of the extracted features. If matches are found, then specific rules are implemented that have been previously stored and associated with the matched shell model or features on the received shell model. If no matches are found, then generalized binaural modeling rules are utilized based on the classified features.