VirDe: a new virtual reality design approach

Virtual reality (VR), even if it does not represent any more a novel technology, is one of the most powerful tool to help designers during the development of new projects. This is proved by very numerous research activities related to this field. In this research, we have studied a new way to approach the development of a product. We present the ongoing development of a system, called VirDe, acronym of virtual design, which can allow the designers to perform the whole design process, from the modelling phase to the finite element method (FEM) simulation analysis, in a virtual reality environment. This new method allows remarkable time and money saving in the overall product design process, but the most important contribution of VirDe is that, as far as we concerned, there is no known similar approach which has been studying the simultaneous combination of CAD, FEM and virtual environment (VE).     

Product–process interface for manufacturing data management as a support for DFM and virtual manufacturing

In order to tackle a continuous improvement of virtual engineering, product modelling has to integrate more knowledge that refers to every decision taken during the product development process. Those decisions have to be related to the assessment of the whole product life cycle. This paper particularly addresses the domain of product’s industrialisation that aims at selecting the manufacturing processes. This selection must currently be done as soon as possible and has to be strongly linked with product definition and computer aided design (CAD) modelling. This work first presents some new results concerning a product–process interface to integrate manufacturing information in the product model and how it leads to the definition of the CAD model. Then this interface that also manages specific information coming from the manufacturing process (tolerances, stresses gradient...) is used to improve the whole manufacturing process plan simulation. This process plan has, indeed, to track every material transformation issued from each manufacturing operation.     

Virtual reality aided design of parts and assemblies

Current virtual reality (VR) systems provide an enormous potential for enhancing the visualization of 3D-design drafts. Based on new navigation techniques the designer is able to interact, model in a more intuitive and efficient way. In our contribution we present a novel interaction metaphor that facilitates the synthesis of efficient virtual reality interaction and visualization techniques with modern feature based CAD systems. We present “NAVIMODE”, an alternative approach for navigation, manipulation and selection, to combine the advantages of VR and CAD systems. The design engineer has the chance to design in his/her habitual environment using the advantage of virtual reality concurrently.     

CAD data workflow toward the thermal simulation and visualization in virtual reality

This paper presents a CAD transfer method to visualize thermal simulation results in a virtual environment in order to optimize building design determined by energy efficiency. As the goal is to present a more immersive thermal simulation and to project the calculation results in projective displays particularly in cave automatic virtual environment, the main idea of the method is to provide a workflow so that the thermal result can be visualized and simulated in the virtual environment (VE). The paper shows the experiment results conducted in an immersion room by some respondents. An evaluation of the method has demonstrated that it is possible to conduct a specific data workflow in order to represent building performance data and particularly thermal simulation results in virtual reality (VR). With this method, the data flow that starts from the design process is completely and accurately channeled to the VR system. CAD data in 3D mock-up models composed of basic geometry are usually designed and transferred to other tools particularly if intended for VR. However, CAD data needed for the VE is not simple, it needs to be structured in a workflow method. Challenges in data exchange and interoperability among design, simulation and VR tools used have become an important issue to investigate how the workflow works.     

A bi-directional interface for improved interaction with engineering models in virtual reality design reviews

Leveraging virtual reality (VR) technology to enhance engineering design reviews has been an area of significant interest for researchers since the advent of modern VR. The ability to interact meaningfully with 3D computer-aided engineering models in these VR design reviews is an important, though often neglected, capability due to the difficulty of performing data translation between native computer-aided design (CAD) data and VR compatible file formats. A bi-directional interface was developed between a VR design review environment and a commercial CAD package that streamlines the data translation process. Transmitting both geometric data and selected metadata from the CAD system enabled the development of enhanced model interaction tools in a VR design review application. User experiments were performed that compared the enhanced tools developed to a baseline toolset. Participants success using these toolsets was measured as they performed tasks related to design understanding and decision making, such as counting the number of gears in a gearbox or evaluating the feasibility of a proposed design change in a four-cylinder engine. The analysis of the data from these experiments showed a statistically significant improvement in participants ability to understand the geometry of the model correctly, confidently, and quickly, as well as in participants ability to correctly and confidently understand the implications of a proposed design change when using the Enhanced Toolset. We conclude that the bi-directional interface concept developed in this work can be extended to enable advanced interaction with a diversity of engineering data in VR.     

Virtual reality approaches for immersive design

The current application of virtual reality (VR) systems in the design process is limited mostly to design review. The reason for this limitation is the different data formats used for CAD and VR visualization. To use the benefits of VR during the design process, solutions for immersive design, the model manipulation inside the VE based on CAD data, are required. There are different approaches allowing VR systems to work as an active development platform. Three examples introduce the realization of the integration of CAD and VR software at different levels by the online coupling of complete applications or by integration of CAD core functionalities in VR systems.     

GARDE: a gesture-based augmented reality design evaluation system

Design evaluation and modification plays a critical role in the design process to develop products that meet the user requirements. Physical prototypes are commonly used to evaluate a design and justify design changes. However, physical prototypes are costly and cannot be modified. Virtual prototypes have been used but it is difficult to simulate virtual prototypes accurately and contextualize them. In this paper, a gesture-based augmented reality design evaluation system (GARDE) is presented. Using AR, GARDE is able to enjoy the benefits of both physical and virtual prototyping in design evaluation. In addition, the use of hand gestures as the main interaction input allows for interactive and intuitive design evaluation. Through the use of an off-the-shelf CAD software API, modifications of the 3D models in an AR environment can be achieved. As design evaluation is conducted in a real environment, in-situ design can also be performed using GARDE. Two case studies have been carried to demonstrate the GARDE system and are described in this paper.     

Design review of CAD assemblies using bimanual natural interface

The interaction metaphor, based on mouse, monitor and keyboard, presents evident limits in the engineering design review activities, when real and virtual models must be explored and compared, and also in “outside-the-office” environments, where the desk is not available. The presented research aims to explore a new generation of gesture-based interfaces, called “natural interfaces”, which promise an intuitive control using free hands and without the desk support. We present a novel natural design review workspace which acquires user motion using a combination of video and depth cameras and visualizes the CAD models using monitor-based augmented reality. We implemented a bimanual egocentric pointer paradigm by a virtual active surface in front of the user. We used a XML configurable approach to explore bimanual gesture commands to browse, select, dis/assembly and explode 3D complex models imported in standard STEP format. Our experiments demonstrated that the virtual active surface is able to effectively trigger a set of CAD specific commands and to improve technical navigation in non-desktop environments: e.g. shop floor maintenance, on site quality control, etc. We evaluated the feasibility and robustness of the interface and reported a high degree of acceptance from the users who preferred the presented interface to a unconstrained 3D manipulation.     

Application of the CMII model to an integrated engineering and manufacturing development environment

In all product development cycles, the change process is one of the most critical elements which must be well controlled. This change process, which is comprised within the configuration management methodology, must be one of the key processes supported by an integrated product development environment which supports the concurrent development of design and manufacturing. The CMII business process model proposed by the Institute of Configuration Management is very well documented and has become a reference for modelling the change process within an enterprise. It was thus proposed to evaluate how this model can be implemented within a virtual product development laboratory at école Polytechnique de Montréal which integrates CAD, PDM and MPM technologies. MPM technologies support manufacturing engineers and process planners for the development and analysis of all manufacturing process information. The study has shown that the CMII business model is totally compatible with the methodologies and technologies supported in the laboratory, but that the existing technologies have to support more sophisticated workflow capabilities to support the CMII model. Moreover, the model was found to foster a highly collaborative product and manufacturing process development environment where both engineering and manufacturing information structures are kept synchronized in real time.     

Mixed reality system for evaluating designability and operability of information appliances

In the product development process, designability and operability are evaluated using physical mock-ups which require high costs and a long time to build. In this paper, virtual mock-ups (3D digital models) are used instead of physical mock-ups to solve these problems of cost and time. Given that designers want to touch and operate the designed product in the evaluation process, to cover the disadvantage of virtual mock-ups which do not allow this, this paper proposes a system for evaluating designability and operability of products under development using mixed reality technology. With the proposed method, a physical mock-up covered with a designed virtual mock-up can be touched and operated to evaluate the design being developed in the mixed space of virtual and real ones from the viewpoint of designability and operability.     

Interactive design of dental implant placements through CAD-CAM technologies: from 3D imaging to additive manufacturing

In the field of oral rehabilitation, the combined use of 3D imaging technologies and computer-guided approaches allows the development of reliable tools to be used in preoperative assessment of implant placement. In particular, the accurate transfer of the virtual planning into the operative field through surgical guides represents the main challenge of modern dental implantology. Guided implant positioning allows surgical and prosthetic approaches with minimal trauma by reducing treatment time and decreasing patient’s discomfort. This paper aims at defining a CAD/CAM framework for the accurate planning of flapless dental implant surgery. The system embraces three major applications: (1) freeform modelling, including 3D tissue reconstruction and 2D/3D anatomy visualization, (2) computer-aided surgical planning and customised template modelling, (3) additive manufacturing of guided surgery template. The tissue modelling approach is based on the integration of two maxillofacial imaging techniques: tomographic scanning and surface optical scanning. A 3D virtual maxillofacial model is created by matching radiographic data, captured by a CBCT scanner, and surface anatomical data, acquired by a structured light scanner. The pre-surgical planning process is carried out and controlled within the CAD application by referring to the integrated anatomical model. A surgical guide is then created by solid modelling and manufactured by additive techniques. Two different clinical cases have been approached by inserting 11 different implants. CAD-based planned fixture placements have been transferred into the clinical field by customised surgical guides, made of a biocompatible resin and equipped with drilling sleeves.     

Visual influence on path integration in darkness indicates a multimodal representation of large-scale space

Our ability to return to the start of a route recently performed in darkness is thought to reflect path integration of motion-related information. Here we provide evidence that motion-related interoceptive representations (proprioceptive, vestibular, and motor efference copy) combine with visual representations to form a single multimodal representation guiding navigation. We used immersive virtual reality to decouple visual input from motion-related interoception by manipulating the rotation or translation gain of the visual projection. First, participants walked an outbound path with both visual and interoceptive input, and returned to the start in darkness, demonstrating the influences of both visual and interoceptive information in a virtual reality environment. Next, participants adapted to visual rotation gains in the virtual environment, and then performed the path integration task entirely in darkness. Our findings were accurately predicted by a quantitative model in which visual and interoceptive inputs combine into a single multimodal representation guiding navigation, and are incompatible with a model of separate visual and interoceptive influences on action (in which path integration in darkness must rely solely on interoceptive representations). Overall, our findings suggest that a combined multimodal representation guides large-scale navigation, consistent with a role for visual imagery or a cognitive map.     

Virtual palpation of skeletal landmarks with multimodal display interfaces

The 3D location of skeletal landmarks on CT datasets is an important procedure, used in many research and clinical contexts. The standard procedure involves the segmentation of the CT images, the creation of a 3D surface bone model, and the location of the landmarks on this surface. However, the segmentation is time-consuming and requires skilled operators and sophisticated software. The aim of the present study is to evaluate the efficacy of a multimodal display interface to direct volumetric interactive visualization in performing a virtual palpation task. An expert operator used the CT dataset of a patient's thigh region to locate 14 femoral skeletal landmarks. This operation was repeatedly performed using different CT data representation; the accuracy and repeatability were compared to those achievable with the conventional procedure based on the segmented 3D surface. When a multimodal display interface (formed by an orthogonal slice, RXCT and interactive isosurface views) was used to perform the virtual palpation directly on the CT data, the average coordinates of the landmarks did not differ significantly from those located on the 3D surface, and the measurement repeatability was actually better with the multimodal display of the volumetric data than with the 3D surface. Thus, we can conclude that skeletal virtual palpation can be performed directly on the CT dataset, as far as the virtual palpation is performed with a multimodal display interface.     

Interactive simulation of CAD models assemblies using virtual constraint guidance

In the context of virtual reality (VR) and of computed aided design (CAD), haptic simulations are used to perform assembly tasks between 3D objects. To ensure the good assembly of those objects, we propose a new method of interactive assembly that uses both kinematic constraints and guiding virtual fixtures. Modelling a haptic assembly task as a combination of mechanical joints, we focus on the guidance of objects and on the activation cues of kinematic constraints in physical simulation. In this article, we first outline the difficulties related to the haptic-assembly of CAD objects in VR simulation. Introducing the virtual constraint guidance (VCG), we present a new method for haptic guidance that decomposes a task in two independent steps: a guiding step which use geometries as virtual fixtures to position objects, and a functional step which use kinematic constraints to perform the assembly task. We finally present a complete application of our method on a peg-in-hole insertion task.     

A systems-engineering approach for virtual/real analysis and validation of an automated greenhouse irrigation system

In the context of multidisciplinary complex systems design, modelling and simulation are key components in decision making. It allow engineers to validate design alternatives at early development stages. Consequently, it is possible to reduce uncertainty on requirements compliance and secure better decisions for downstream stages of product development. This article describes the analysis of a virtual prototype of an automated greenhouse irrigation system. It is modelled and compared with the real system implementation, finding some differences and similarities between both system testing approaches. The intrinsic dependence of experimentation and modelling is also discussed as both, experimental and random data, are important to be used as inputs to validate virtual models.     

Innovative assembly process for modular train and feasibility analysis in virtual environment

The present paper deals with the manufacturing process of a railway carriage. In the first part of the paper, the authors focus on a “virtual railway factory” that uses a very innovative assembly cycle, if compared to the traditional manufacturing processes in the railway field. The case study refers to a railway carriage consisting of four modules, that are singularly set up of furnishings and other systems in dedicated workplaces. On one hand, the virtual simulation has highlighted several critical aspects to be improved, in order to achieve a greater feasibility and to reduce time and cost. On the other hand, the designers have been able to evaluate the movements of the parts and the assembly sequences of the components, by considering each geometric, functional and technological constraint and also some safety requirements. The second part of the paper deals with the simulation of the assembling operations and the analysis of tolerance chains, which have been performed through a Computer Aided Tolerancing system. In particular, the precision requirements have been also evaluated and we have compared the accumulation of dimensional and geometric deviations when using both rivets and traditional welds to fasten the modules.     

A Non-Geodesic Trajectory Design Method and Its Post-Processing for Robotic Filament Winding of Composite Tee Pipes

With the advantages of high specific strength and well corrosion resistance, polymer-matrix composite tee pipes are widely used in aerospace and civilian fields. The robotic filament winding technology is suitable for forming complex shape parts. This paper aims to provide a novel non-geodesic trajectory design method to get a continuous trajectory for tee pipe winding. Furthermore, post-processing methods are proposed for realizing the full coverage of tee pipes by robotic filament winding. The CAD/CAM software is then designed to simulate the winding process and realize the cover of the whole tee pipe. Finally, experiments of winding a tee pipe with a desktop winding machine and a six-axis winding robot are carried out. The results show that the tee pipe is fully covered, verifying the accuracy of the design method and post-processing methods.     

Virtual concepts and experiments to improve quality of train interiors

The paper aims at providing a methodological contribution to the concept design of train interior in order to improve the quality perceived by users in compliance with railway standards. Indeed, the combined use of advanced CAD tools, experimental statistical methods and Virtual Reality tools allows developing, selecting and experimentally evaluating new concepts. The design cycle starts both from designers’ proposal and the identification of user’s needs; then, it makes use of datum-based CAD models in order to generate virtual concepts that satisfy railway standards; the cycle proceeds with the immersive evaluation of virtual prototypes, performed by potential and expert users in Virtual Reality. The identification of the optimal concept closes the design process. This procedure can be iterated in order to improve the quality of train interiors, evaluated thanks to the user’s involvement in the design cycle. In this work a case study on seat design of a regional train is presented, developed at the Virtual Reality laboratory, named VRTest, of the Regional Centre for the qualification of transportation systems set up by Campania Regional Authority.     

Advanced computer aided technologies for design automation in footwear industry

In the footwear industry there is growing methodological research linking advanced computer-based technologies to the traditional manufacturing process. This paper deals with the automation of shoe design phases and describes a computer aided design system that brings together theories and tools from geometric modeling, image processing, and reverse engineering. At first, the paper reviews the current technologies used for creating new shoe models. Then the paper presents an approach based on shoe 3D virtual modeling in order to overcome the traditional time-consuming manual operations. The approach is concretized into dedicated tools able to automatically perform design of the last shape model and flattening of the shoe styling curves represented in the virtual prototype. The modeling tool uses 3D geometric rules derived from the analysis of strategies adopted by skilled manual operators, while the styling curves recognition and flattening are based on specific image processing algorithms and geometrical deformation rules. Experimental results show a good compromise between quality results and modeling time.     

Tangible image studio for digital imaging in product design

We introduce a system for supporting digital imaging tasks in product design, called Tangible Image Studio. Tangible Image Studio helps industrial designers intuitively control parameters for digital imaging, such as camera location, target location, type and property of light sources in 3D CAD tools by employing tangible user interface techniques. It can improve the user interface of digital imaging tasks in CAD. It is also useful as a teaching aid for photographic studio lighting.