Abstract: A reverse engineering technique allows the creation of 3-D CAD files from a solid model. A solid model of a part to be reverse engineered is created from polymers having an index of refraction matching that of an immersion liquid. Over the immersion liquid is a masking liquid that is substantially opaque. The generally clear polymeric model of the part is moved through the immersion/masking layer interface while images of the cross section of the model are acquired at the interface layer. The images are then used to create digital solid models from a physical model or to compare an existing physical model with its digital model.