Virtual and augmented reality

Commonly, during the aesthetic design process, stylists sketch features called character lines over a simple and "uninteresting" geometry (e.g. a car bonnet) in order to confer personality, emotional feeling and style. This work presents an original interface paradigm for character line sketching in a virtual reality environment. Taking advantage of the 3D interface, the feature path, also called leading line, can be directly sketched on the initial surface by realtime projection. Afterwards, a semi-transparent section is selected along the path in a interactive way and then the feature profile is sketched on this plane according the user's intention. Subsequently, by moving the virtual pen forwards along the path, the character line is generated, on the contrary if the pen is moved backwards the feature is partially erased. The distance of the virtual pen from the leading line controls, in real time, the offsetting along the path of the feature which remains consistent in style and identity. Such a system has been proven to be a powerful tool for fast expression and evaluation of ideas, which can be, in subsequent design phases, integrated with detailed surfacing applications and prototyping.

Keywords: Constrained-based design , Curve and surface design , Feature-based design , Parametric modelling

Spacedesign is an innovative mixed reality (MR) application addressed to aesthetic design of free form curves and surfaces. It is a unique and comprehensive approach which uses task-specific configurations to support the design workflow from concept to mock-up evaluation and review. The first-phase conceptual design benefits from a workbench-like 3-D display for free hand sketching, surfacing and engineering visualization. Semitransparent stereo glasses augment the pre-production physical prototype by additional shapes, textures and annotations. Both workspaces share a common interface and allow collaboration and cooperation between different experts, who can configure the system for the specific task. A faster design workflow and CAD data consistency can be thus naturally achieved. Tests and collaborations with designers, mainly from automotive industry, are providing systematic feedback for this ongoing research. As far as the authors are concerned, there is no known similar approach that integrates the creation and editing phase of 3D curves and surfaces in virtual and augmented reality (VR/AR). Herein we see the major contribution of our new application.

This paper outlines new trends in geometric modelling, showing how systems are moving from a geometry-based approach to a physically-based approach. The possibility to simulate the actual behaviour of a product is at the basis of Virtual Prototypes that are becoming a common practice in today's product development process. As a consequence, also interaction modalities and techniques have to be improved in order to satisfy new system requirements and functionalities. The research work described in this paper shows how haptic interaction techniques represent an evolution of current interaction technologies providing intuitive and realistic modalities for interacting with virtual applications. In particular, the paper describes a research work we have carried out integrating haptic technologies together with physically-based modelling and simulation techniques. © 2001 Springer Science+Business Media New York.

Keywords: Haptic interaction , Human-computer interaction , Non-rigid material modelling , Physically-based modelling , Virtual prototyping

The definition of a restoration project for a historical-artistic building is a high-skill operation. The preliminary survey and the following graphic representation of the artefacts, in particular, are two critical phases for good final results. The representation techniques called vectorial, including also the analytic photogrammetry, are nowadays surpassed by the wide introduction of digital techniques like the digital photogrammetry because of to excellent reproduction and low cost. Our paradigm for building restoration starts with a three-dimensional model of an edifice extracted from a set of 2-dimensional image using specific Image Assisted Modelling software. This digital model represents the artefacts both in its metric and morphologic complexity. Basically the result is a fully three-dimensional wireframe model with dimensional information while the appearance features are defined as a collection of bi-dimensional textures attached to the faces of the model. The most innovative aspect is the possibility to simulate the restoration process in two separate streams. On one side it is possible to adjust the original textures using common bi-dimensional digital painting software or specific tools that allow the user to interact with a three-dimensional image. On the other side, virtual environments permit to modify the model defining the dimension according to the desiderate restoration goal. We propose a new restoration project paradigm that integrates these innovative tools where artists and engineers work together and interactively. The restoration process is visualized in a specific immersive virtual environment developed by the authors in the VR3lab at Polytechnic of Bari-Italy. This is definitively an efficient way for designers, control agencies and building companies to immediately evaluate different solutions.

The definition of a restoration project for a historical-artistic building is a highskill operation. The preliminary survey and the following graphic representation of the artefacts, in particular, are two critical phases for good final results. The representation techniques called vectorial, including also the analytic photogrammetry, are nowadays surpassed by the wide introduction of digital techniques like the digital photogrammetry because of to exceIIent reproduction and low cost. Our paradigm for building restoration starts with a threedimensional model of an edifice extracted from a set of 2-dimensional image using specific Image Assisted Modelling software. This digital model represents the artefacts both in its metric and morphologic complexity. Basically the result is a fully 'three-dimensional wirefiame model with dimensional information while the appearance features are defined as a collection of bi-dimensional textures attached to the faces of the model. The most innovative aspect is the possibility to simulate the restoration process in two separate streams. On one side it is possible to adjust the original textures using common bi-dimensional digital painting software or specific tools that allow the user to interact with a three-dimensional image. On the other side, virtztal environments permit to modify the model defining the dimension according to the desiderate restoration goal. We propose a new restoration project paradigm that integrates these innovative tools where artists and engineers work together and interactively. The restoration process is visualized in a specific immersive virtual environment developed by the authors in the VR3lab at Polytechnic of Bari-Italy. This is definitively an efficient way for designers, control agencies and building companies to immediately evaluate different solutions.

Haptic interfaces represent a revolution in human computer interface technology since they make it possible for users to touch and manipulate virtual objects. In this work we describe a cross-model interaction experiment to study the effect of adding haptic cues to visual cues when vision is not enough to disambiguate the images. We relate the results to those obtained in experimental psychology as well as to more recent studies on the subject.

A prst step towards a semi-immersive Virtual Reality (L!R) interface for Finite Element Analysis (FEA) is presented in this paper. During recent years, user interfaces of FM solvers have matured from characterbased command-line driven implementations into easy-touse graphical user interfaces (GUS). This new generation of GUIs provides access to intuitive and productive tools for the management and analysis of structural problems. Many pre-And post-processors have been implemented targeting the simplification of the manmachine interface in order to increase the ease of use and provide better visual analysis of FEA solver results. Nevertheless, none of these packages provides a real 3Denabled interface. The main objective of this project is to join state-of-The-Art visualization technology, VT devices, and FM solvers into the integrated development environment VRFM.

Keywords: 3D Modeling , Finite Element Analysis , Interactive Modeling , Simulation. , Virtual Reality

Virtual Environments (VEs) have the potential to revolutionize traditional product design by enabling the transition from conventional CAD to fully digital product development. The presented prototype system targets closing the "digital gap" as introduced by the need for physical models such as clay models or mockups in the traditional product design and evaluation cycle. We describe a design environment that provides an intuitive human-machine interface for the creation and manipulation of three-dimensional (3D) models in a semi-immersive design space, focussing on ease of use and increased productivity for both designer and CAD engineers.

Keywords: 3D sculpting , Computer aided geometric design (CAGD) , Immersive environments , Virtual reality

This paper describes the preliminary results of the research work currently ongoing at the University of Parma, and partially carried out within a basic research project funded by the European Union. The research work aims at applying the techniques used in gesture analysis and recognition for understanding human skill performed for non rigid object grasping and manipulation. The various grasping gestures have been classified on the basis of some quantitative features extracted from the hand gesture analysis. Finally, it is planned to map the formalized skill into a robotics system, that will be able to grasp and manipulate non rigid objects, also facing unexpected situations.

User interfaces of current 3D and virtual reality environments require highly interactive input/output (I/O) techniques and appropriate input devices, providing users with natural and intuitive ways of interacting. This paper presents an interaction model, some techniques, and some ways of using novel input devices for 3D user interfaces. The interaction model is based on a tool-object syntax, where the interaction structure syntactically simulates an action sequence typical of a human's everyday life: One picks up a tool and then uses it on an object. Instead of using a conventional mouse, actions are input through two novel input devices, a hand- and a force-input device. The devices can be used simultaneously or in sequence, and the information they convey can be processed in a combined or in an independent way by the system. The use of a hand-input device allows the recognition of static poses and dynamic gestures performed by a user's hand. Hand gestures are used for selecting, or acting as, tools and for manipulating graphical objects. A system for teaching and recognizing dynamic gestures, and for providing graphical feedback for them, is described. © 1994, Taylor & Francis Group, LLC. All rights reserved.