Imposing Geometric Constraints on Virtual Objects within an Immersive Modeler

This paper describes an intuitive and efficient way to design not only 3-D shapes but also their geometric constraints within an immersive modeler. The fundamental concept of the proposed method is based on our immersive modeler VLEGO II, which allows multiple users to create 3-D virtual objects only by assembling simple 3-D geometric shapes (shape primitives) like with real toy blocks. In our system, geometric constraints are presented as primitives (constraining primitives) like normal shape primitives, and the geometric constraints are imposed on virtual objects simply by assembling shape and constraining primitives. The system also provides flexible two-handed interaction to support intuitive and efficient manipulations.