Research On Feature-based Automatic Modeling Of Transition Areas In Car Body Parts

With the body design in the vehicle development process becoming increasingly important, people raised higher demands on the quality of auto body model and modify aspect. If use the general of CAD tools, it is a time-consuming and complicated process, when the designers want to obtain a detailed description of the auto body of the geometric structure of the digital model. In order to make this process becomes quick and reliable, many designers are looking for all kinds of improved design method. Auto body as much as possible to achieve the parameters of the modeling process, is one of the ways.Beam structure is the main structural component of the body. Beam structure in different regions of the transition generation is a type frequently encountered situations in a auto body three-dimension modeling process. However beam structure is often vastly different, so the manual creation of regional transition process is very complex and cumbersome. Moreover, once the beam changes in the structure, associated with the transition region need to re-create the design staff, which consume a great deal of valuable time. This repeated process is serious constraints on the model update speed and affects the efficiency of product development. If this part of the modeling process can achieve automatic modeling based on the characteristics of the process, it will greatly enhance the work efficiency of the design. At the same time it plays an important role in facilitating the ultimate realization of the whole auto body of parametric modeling. Therefore, it is of great significance to research on feature-based automatic modeling of the body beam structure of the transition region.In this paper, with UG / NX software platform, the combination of UG / Open API, KF, Block Styler, and other development tools, developed a body beam structure of the transition region based on the characteristics of the parameters of creation modules. As a global leader in PLM software development and services company, UG / NX software development a lot of automotive design automation module. Faced with the current users of the requirements of the three-dimensional model cars continuously improve, it raises the concept of body structure CVA (Concept Vehicle Architecture project), as envisaged eventually to the full realization of the entire body design parameter. This paper discusses the Transition Module, it is on this background, a combination of the practical requirements of vehicle manufacturers, was proposed.The main purpose of this paper is: avoid the cumbersome body beam structure transition region in the manual process of creating and realizing this process based on the characteristics of parametric design, changes in the structure of the beam, associated with the transition region can be adjusted automatically. At the same time, the use of features and the creation process of the features in UG/NX software is summarized.According to the above-mentioned purposes, the paper launched the following main aspects:⑴Familiar with the manual creation of the regional body beam structure of the transition process, and create derived from the main steps.①beam structure will be connected into the edge of bridge in accordance with a reasonable order.②through two adjacent bridge curves, as well as bridging the section line between them creating a transition surface.③from the remaining section of the bridge and the closure of the region surrounded by N-sided Surface create surface.④sew the various surface together to become a whole.⑵Design the overall process framework, by extracted from the main steps of manual method. The work needed to complete, as well as the algorithm in the steps is discussed, including the selected section of the bridge online unified point of order, determine the section line between reasonable direction, create different beam cross-section of the bridge curve, the criteria of adding bridging point were analyzed when cross-section of the bridge between the number of points not the same ,need to add auxiliary bridge, in accordance with certain rules, the transition will be divided into regional side and bottom two types, then use the creation of different surfaces methods in UG / NX software to generate surfaces. ⑶In UG/NX6 platform, completed the implementation of procedures , by integrating application of a variety of development tools. Use the latest software interface development module to design the interface.⑷This paper made a summary on the characteristics of the application software advantages and characteristics of the process of creating in NX software. NX software features can be intuitively understood as a model of the navigation tree's every step, every node. Feature provides a method of object-oriented design approach. It can be inside the packaging of various attributes and function , so it can be extended to include engineering significance of the geometric prototype. NX software to create characteristics of the process, summed up the following basic steps:(1) In accordance with the specific requirements for the design of new feature functions.(2) Definition of the characteristic parameters of the new category.(3) To achieve the necessary characteristics of the function.(4) To set the characteristics of the necessary attributes.(5) To create and edit features to implement characteristics of the function.(6) Implementation interactive between interface, UG / OPEN and KF.In addition, this paper, the actual operation of the module has done examples, including the creation of Transition features, edit Transition features in detail, also on the characteristics of the adaptive features of the application.This paper focused on in the car body modeling process solving on different beam structure with the transition region between the characteristic parameters of the relationship. Using NX software platform, Beam structure will be the formation of regional transition process designed to be a feature-based automatic process modeling. The function can guarantee that the transition region with the beam and changes in the structure of automatic adjustment. The development of the functional modules, can avoid in the car design stage, due to changes in the structure of the beam need to re-create the tedious process of the transition region. It has laid the foundation to improve efficiency and enhance the analysis of the concept of auto body accuracy. In addition, using the latest UG/NX6 software interface development tools, and the creation of the characteristics of the process are described in this paper. It has some role in guiding on the application of a body design of this software in terms of researchers.