In this paper, we present a prototype system for robust, interactive and user friendly modeling of orientable 2-manifold meshes. To develop the system we introduce new topological entities for effectively manipulating 2-manifold mesh structures. We identify a minimal set of fundamental operators, which is necessary and sufficient for performing all homeomorphic and topological operations on 2-manifold mesh structures. Extremely efficient algorithms are developed for the implementation of these operators. We also developed a set of powerful, user-friendly, and effective operators at the level of user-interface. Users of our system can perform a large set of homeomorphic and topological changes with these user-interface level operators. Our system is topologically robust in the sense that users will never create invalid 2-manifold mesh structure with these operators.

In our system, the homeomorphic and topological surgery operations can be applied alternatively n 2-manifold meshes. With our system, users can blend surfaces, construct crusts and open holes on these crusts. With our system, the shapes that look like solid, non-manifold, or 2-manifold with boundary can be manipulated. The system also provides automatic texture mapping during topology changes.