Modeling (seemingly) impossible models

In recent years, there has been a growing interest in computer graphics and geometric modeling in the ability to create and manipulate Seemingly Impossible Models (SIMs). Methods to create derivative work and modify drawings and paintings of SIMs made by artists were suggested. Similarly, 3D realization of SIMs of some of these drawings were also offered. In this work, we further explore the nature of SIMs and identify a class of SIMs that can be realized and modeled in 3D. As part of this analysis we show an invariance whose preservation allows one to model SIM artifacts that are completely realizable. We further present a mini-modeling package that allow end-users to realize whole new SIMs in two stages: modeling a regular 3D model and then converting it into a SIM using special deformations. We conclude with some examples, a discussion on the current limitations, and a layout of possible future work. keywords: Impossible 3D Models, M. C. Escher, Non realistic modeling (NRM), Art in science.