Direct 3D Manipulation Techniques for Interactive Constraint‐based Solid Modelling

Abstract

AbstractThis paper presents a novel constraint‐based 3D manipulation approach to interactive constraint‐based solid modelling. This approach employs a constraint recognition process to automatically recognise assembly relationships and geometric constraints between entities from 3D manipulation. A technique referred to as allowable motion is used to achieve accurate 3D positioning of a solid model by automatically constraining its 3D manipulation without menu interaction. A set of virtual design tools, which can be used to construct constraint‐based solid models within a virtual environment, are also supported. These tools have been implemented as functional 3D objects associated with several pre‐defined modelling functions to simulate physical tools such as a drilling tool and T‐square. They can be directly manipulated by the user, and precisely positioned relative to other solid models through the constraint‐based 3D manipulation approach. Their modelling functions can be automatically triggered, depending upon their associated constraints and the user's manipulation manner. A prototype system has been implemented to demonstrate the feasibility of these techniques for model construction and assembly operations.