Computing Design Rationales by Interpreting Simulations*

* Support for this project was provided by the Advanced Research Projects Agency of the Department of Defense under Office of Naval Research contract N00014-96-1-0750. ABSTRACT We describe an approach for automatically computing a class of design rationales. Our focus is computing the purposes of the geometric features on the parts of a device. We first simulate the device with the feature in question removed and compare this to a simulation of the nominal device. The differences in the simulations are indicative of the behaviors that the feature ultimately causes. We then use fundamental principles of mechanics to construct a causal explanation that links the feature to these behaviors. This explanation constitutes one of the rationales for the feature. We have implemented a program that can construct these kinds of causal explanations and have tested it on various examples.