Computation of Components' Interfaces in Highly Complex Assemblies

International audienceThe preparation of CAD models from complex assemblies for simulation purposes is a very time-consuming and tedious process, since many tasks \rev{such as meshing and idealization} are still completed manually. Herein, the detection and extraction of geometric interfaces between components of the assembly is of central importance not only for the simulation objectives but also for all necessary shape transformations such as idealizations or detail removals. It is a repetitive task in particular when complex assemblies have to be dealt with. This paper proposes a method to rapidly and fully automatically generate a precise geometric description of interfaces in generic B-Rep CAD models. The approach combines an efficient GPU ray-casting technique commonly used in computer graphics with a graph-based curve extraction algorithm. Not only is it able to detect a large number of interfaces efficiently, but it also provides an accurate Nurbs geometry of the interfaces, that can be stored in a plain STEP file ~\cite{step:1994} for further downstream treatment. We demonstrate our approach on examples from aeronautics and automotive industry

Automatic Extraction of Assembly Component Relationships for Assembly Model Retrieval

AbstractEven if during the Product Design Process, assembly models are described in terms of their constitutive components and associated relationships, only the position of each component is often stored within the Digital Mock-Up. Thus, the mating information are lost. However, these relationships are crucial for many applications, such as retrieval, assembly planning and finite element simulations. In this paper, we propose a method for the detection and use of the mating relationships for assembly model retrieval. The proposed approach detects and analyses the interferences between parts to compute their degree of freedom and kinematic pairs. To support the retrieval of assembly models, the extracted information are formalized and capitalized in a newly proposed hierarchical assembly model descriptor. Results of the application of the method are also provided to show the system capabilities. Moreover, considering that a same joint can be defined in multiple ways, this work provides also a method for retrieving assemblies in a dataset according to the part relationships and their class of equivalence