Desktop haptic virtual assembly using physically based modelling

This research investigates the feasibility of using a desktop haptic virtual environment as a design tool for evaluating assembly operations. Bringing virtual reality characteristics to the desktop, such as stereo vision, further promotes the use of this technology into the every day engineering design process. In creating such a system, the affordability and availability of hardware/software tools is taken into consideration. The resulting application combines several software packages including VR Juggler, open dynamics engine (ODE)/open physics abstraction layer (OPAL), OpenHaptics, and OpenGL/GLM/GLUT libraries to explore the benefits and limitations of combining haptics with physically based modelling. The equipment used to display stereo graphics includes a Stereographics emitter, Crystal Eyes shutter glasses, and a high refresh rate CRT Monitor. One or two-handed force feedback is obtained from various PHANTOM haptic devices from SensAble Technologies Inc. The application’s ability to handle complex part interactions is tested using two different computer systems, which approximate the higher and lower end of a typical engineer’s workstation. Different test scenarios are analyzed and results presented.     

VR-CAD integration: Multimodal immersive interaction and advanced haptic paradigms for implicit edition of CAD models

This paper presents an approach for the integration of Virtual Reality (VR) and Computer-Aided Design (CAD). Our general goal is to develop a VR-CAD framework making possible intuitive and direct 3D edition on CAD objects within Virtual Environments (VE). Such a framework can be applied to collaborative part design activities and to immersive project reviews. The cornerstone of our approach is a model that manages implicit editing of CAD objects. This model uses a naming technique of B-Rep components and a set of logical rules to provide straight access to the operators of Construction History Graphs (CHG). Another set of logical rules and the replay capacities of CHG make it possible to modify in real-time the parameters of these operators according to the user’s 3D interactions. A demonstrator of our model has been developed on the OpenCASCADE geometric kernel, but we explain how it can be applied to more standard CAD systems such as CATIA. We combined our VR-CAD framework with multimodal immersive interaction (using 6 DoF tracking, speech and gesture recognition systems) to gain direct and intuitive deformation of the objects’ shapes within a VE, thus avoiding explicit interactions with the CHG within a classical WIMP interface. In addition, we present several haptic paradigms specially conceptualized and evaluated to provide an accurate perception of B-Rep components and to help the user during his/her 3D interactions. Finally, we conclude on some issues for future researches in the field of VR-CAD integration.     

Quantitative assessment of the effectiveness of using display techniques with a haptic device for manipulating 3D objects in virtual environments

Quantitative assessment is made of using two display techniques, providing two different levels of depth perception, in conjunction with a haptic device for manipulating 3D objects in virtual environments. The two display techniques are 2D display, and interactive 3D stereoscopic virtual holography display on a zSpace tablet. Experiments were conducted, by several users of different ages and computer training. The experiments involved selected pointing and manipulation tasks. The speed of performing the tasks using the two display techniques were recorded. Statistical analysis of the data is presented. As expected, the use of interactive 3D stereoscopic display resulted in faster performance of the tasks. The improvement in performance was particularly noticeable for the cases wherein the subjects needed to manipulate the haptic arm to reach objects/targets at different depths, and also when the objects/targets were occluded partially by the obstacles.     

Generating 3D interaction techniques by identifying and breaking assumptions

Researchers have created 3D interaction techniques for immersive virtual worlds, but existing techniques represent just part of the design space. While exploring other parts of the design space might yield more effective techniques, conducting that exploration is difficult and time-consuming. Analyzing the particular task, user, and hardware characteristics for any given problem is straightforward, but only suggests the shape of a potential technique; generating the technique itself still requires a creative breakthrough. We propose extending existing approaches to generating 3D interaction techniques by focusing more explicitly on identifying and breaking assumptions about the real world to inspire potential technique ideas. We describe our approach, suggest an initial list of assumptions to consider, and present a case study of applying the process to create a technique for navigation with visible landmarks and place representations.     

基于虚拟现实的三维建筑造型和装修设计系统

为了在进行建筑造型和装修设计时,要完成_二维建模、三维场景实时模拟和仿真动画制作、施T图绘制等不同过程,需要不同的软件;如何在一个系统中实现上述不同仿真过程的有效结合,是现实设计中的一个难题.研究了基于虚拟现实的三维建筑造型和装修设计系统,论述了基本的系统仿真原理,提出了基于虚拟现实的仿真系统的新架构,并描述了仿真系统需要的虚拟现实,仿真设计,三维渲染和动画设计等重要技术手段,最后结合实际应用验证了仿真系统的有效性.系统成功地将三维建模、渲染、动画及配景贴图、施工图绘制等多项功能集成化,充分满足了设计者的需求.系统作为商品化软件已经应用,提高了建筑装修设计的整体工作效率.     

基于重力坝三维设计的CAD动态交互系统开发

为了在可研阶段合理、快速地制定重力坝设计方案,减少设计周期和成本,采用极限状态设计的方法,利用VB 6.0可视化编程工具开发出了一套能够与CAD动态交互的重力坝三维设计系统。该系统通过对Auto-CAD的二次开发实现了重力坝的三维参数化建模,并对所建三维模型进行结构计算,将设计与计算紧密结合,通过动态交互简化了大量复杂数据的计算,达到精确、快速完成断面设计的目的。经实践检验证明,该系统大大提高了断面设计效率,实用性强,对可研阶段的方案比选具有重大意义。     

Applying a 3D virtual learning environment to facilitate student’s application ability - The case of marketing

In order to understand whether a 3D virtual learning environment is effective in facilitating students’ application ability, we designed a 3D virtual supermarket (3DVS) to help business students to transform abstract class theory into concrete application ability in the real world. In the 3DVS, a virtual customer poses questions to the participant, and then the participant, as a simulated clerk, has to reply to the questions. All of the questions in the 3DVS were developed from marketing mix theory and given a scenario-based form. To understand the effects of the 3DVS, the participants were randomly divided into control group (CG) and experiment group (EG), and only the EG participants were trained with the 3DVS. After examined by pretest and posttest, the results of posttest indicated that the participants of the EG performed significantly better in terms of knowledge application than did those of the CG.