3D Scenario Building System With Tooling For Assembly Simulation

Rapid construction of a 3D assembly scenario is an important basis for virtual assembly simulation, but assembly scenario constructed by a single product has been unable to meet the requirement of the increasingly plentiful scene data. According to the actual needs of the digital factory, this thesis conducted a thorough research on main key technology of the scene layout, designed and developed an integrated 3D scene layout system for assembly simulation which consists of products, tools and tooling.On account of information integrity of assembly model as well as manageability of model data under virtual environment, By adopting data model with assembly features and using the secondary development for three-dimensional CAD software method, this thesis gets structural information, positional and attitude information of the assembly parts, reorganizes the scene objects’ structure, establishes a hierarchical tree structure, meanwhile, associates the assembly features with the parts, tools, tooling and products.To achieve a precise definition and layout of relative position of products, tools, tooling in three-dimensional assembly scene, the thesis analyzes ACIS’s B-rep(boundary representation model) structure, especially the topological properties of the boundary representation method entities, and the define and classify the common assembly relationships, then gets a mathematical expression of the feature elements by making topological analysis of assembly characteristics involved in each assembly relationship.To compose an assembly scene quickly, this thesis analyzes in detail the algorithm of ray collision detection in 3D assembly scene, which can pick up objects in the 3D assembly scene. According to their hierarchical model structure, the objects’ assembly feature is picked up in real-time. In line with geometry data from the assembly feature, positional and attitude information matrix is created, which will update scene objects’ position and attitude information.To meet the actual demand that the scene layout is easily modified and interacts with the assembly simulation verification system, 3D scene files based on XML language will be used in the subsequent verification and application of the three-dimensional assembly simulation verification system. By using SDK of the HOOPS / ACIS under Visual C ++ 6.0 integrated development environment, an integrated 3D scenario layout system for assembly simulation which consists of products, tools and tooling is created to verify this thesis’ s practicality and efficiency.