摘要
Constraint-based solid modeling is the kernel part of current CADsystems. It has been widely used in supporting detailed design and variational design. However, it cannot support early stage design and is not easy-to--use becauseit demands fully detailed input description of a design. To solve these problems,researchers attempt to incorporate virtual reality techniques into geometric modeling systems. This paper presents a novel approach for interactive constraint-basedsolid modeling in a virtual reality environment. The approach allows the designerto construct and edit a constraint-based solid model by direct 3D manipulations,and ensures the created solid model to be precise by recognizing and solving geometric constraints. To effectively support 3D manipulations and change propagation,a new constraint-based solid model is adopted. In the model, besides the normalconstituents of the typical constraint-based solid model, some new attributes likeshape control points, location pattern and explicit shape constraints of a primitiveare defined. Guided by the location pattern, our algorithms for recognizing andsolving location constraints are real-time.
Constraint-based solid modeling is the kernel part of current CADsystems. It has been widely used in supporting detailed design and variational design. However, it cannot support early stage design and is not easy-to--use becauseit demands fully detailed input description of a design. To solve these problems,researchers attempt to incorporate virtual reality techniques into geometric modeling systems. This paper presents a novel approach for interactive constraint-basedsolid modeling in a virtual reality environment. The approach allows the designerto construct and edit a constraint-based solid model by direct 3D manipulations,and ensures the created solid model to be precise by recognizing and solving geometric constraints. To effectively support 3D manipulations and change propagation,a new constraint-based solid model is adopted. In the model, besides the normalconstituents of the typical constraint-based solid model, some new attributes likeshape control points, location pattern and explicit shape constraints of a primitiveare defined. Guided by the location pattern, our algorithms for recognizing andsolving location constraints are real-time.
