In this paper, we describe a case study using 3D conversational modeling as an approach to the design of an online interactive system. The system was intended to help customers select electric motors from a wide range of options, and to be used on its own by a customer, or else in conversations between customers and salespeople or motor experts. The primary function, however, was to encourage selection and input of relevant information from the customer. It was in meeting this goal that the conversational modeling was most useful, since it suggested not only the types of information that were central to the process, but also an appropriate structure. Our user study had 17 participants matching motors using the current online Motor Match system and two prototype versions produced by the research team. One of the most significant findings was the participants' interest in the ranking of near-match motors displayed as 'possible matches'. In addition, people using the prototype systems found the correct motor as often as the current online system (prototype 1), or more often (prototype 2), and ranked their level of confidence higher than users of the current system.