Athanasios Gaitatzes

Reviving the past: cultural heritage meets virtual reality

The use of immersive virtual reality (VR) systems in museums is a recent trend, as the development of new interactive technologies has inevitably impacted the more traditional sciences and arts. This is more evident in the case of novel interactive technologies that fascinate the broad public, as has always been the case with virtual reality. The increasing development of VR technologies has matured enough to expand research from the military and scientific visualization realm into more multidisciplinary areas, such as education, art and entertainment. This paper analyzes the interactive virtual environments developed at an institution of informal education and discusses the issues involved in developing immersive interactive virtual archaeology projects for the broad public.

The ancient olympic games: being part of the experience

This paper presents the virtual reality applications that the Foundation of the Hellenic World has produced associated with the Olympic Games in ancient Greece. The separate virtual reality shows are presented in terms of interactivity and educational value. The technical aspects of the productions are next explained in detail, with an emphasis on character animation, dynamics and occlusion culling for surround screen projection environments. These techniques were mostly utilised in the recent production regarding the ancient pentathlon, where much effort has been made to recreate the feeling of the games and help the user/spectator be an interacting part of the edutainment activity.

Media productions for a dome display system

As the interest of the public for new forms of media grows, museums and theme parks select real time Virtual Reality productions as their presentation medium. Based on three-dimensional graphics, interaction, sound, music and intense story telling they mesmerize their audiences. The Foundation of the Hellenic World (FHW) having opened so far to the public three different Virtual Reality theaters, is in the process of building a new Dome-shaped Virtual Reality theatre with a capacity of 130 people. This fully interactive theatre will present new experiences in immersion to the visitors. In this paper we present the challenges encountered in developing productions for such a large spherical display system as well as building the underlying real-time display and support systems.

Multi-view ambient occlusion with importance sampling

Screen-space ambient occlusion and obscurance (AO) techniques have become de-facto methods for ambient light attenuation and contact shadows in real-time rendering. Although extensive research has been conducted to improve the quality and performance of AO techniques, view-dependent artifacts remain a major issue. This paper introduces Multi-view Ambient Occlusion, a generic per-fragment view weighting scheme for evaluating screen-space occlusion or obscurance using multiple, arbitrary views, such as the readily available shadow maps. Additionally, it exploits the resulting weights to perform adaptive sampling, based on the importance of each view to reduce the total number of samples, while maintaining the image quality. Multi-view Ambient Occlusion improves and stabilizes the screen-space AO estimation without overestimating the results and can be combined with a variety of existing screen-space AO techniques. We demonstrate the results of our sampling method with both open volume- and solid angle-based AO algorithms.

Enhancing virtual reality walkthroughs of archaeological sites

This paper describes the methodological aspects of the application of various established and new graphics techniques in virtual reality applications, in order to visually enrich conventional walkthroughs and extend the common capabilities of virtual environment visualization platforms. The paper describes these techniques and goes to the extent of explaining various practical implementation issues. Examples and application case studies are provided to demonstrate the enhancements.

Virtual reality systems and applications: the ancient olympic games

This paper presents the virtual reality systems, interaction devices and software used at the Foundation of the Hellenic World (FHW). The applications that FHW has produced, associated with the Olympic Games in ancient Greece, are then detailed. The separate virtual reality shows are presented in terms of interactivity and educational value. Technical aspects of the productions are explained, with an emphasis on surround screen projection environments. These techniques were mostly utilized in the recent production regarding the ancient Olympic Games, where much effort has been made to recreate the feeling of the games and help the user/spectator be an interacting part of the edutainment activity.

Multimodal Interfaces for Educational Virtual Environments

Educational applications often are slow to leverage and use new interaction devices in order to bring new value and allow new forms of gameplay. Following decades of research on how to use 3D simulation and Virtual Environments in education, attention has recently turned to exploring Multi-User-Virtual-Environments for the educational community. In the following paper we present the results of a pilot simulation battle, created for educational purposes combining the positive aspects of multi-user virtual environments, edutainment VR applications and new Human Computer Interaction (HCI) interfaces. We present the technology used, as well as an evaluation case study of the human-computer interaction results.

Virtual reality systems and applications

In this tutorial we will present the infrastructure required, both software and hardware, to create the Virtual Reality (VR) illusion. The history and the application areas of VR will be presented. From the software required to the image generator to the different display systems -- both head based and projection based -- all components of a VR system as well as practical deployment issues will be investigated. The stereo depth principle will be explained along with the different stereo methodologies available today. Aspects of a VR experience like immersion and collaboration will be explored. Other topics include the physical interface and interaction devices and the methods of manipulating a Virtual Environment by tracking users and devices.An attempt will be made to differentiate VR from pre-rendered Computer Graphics by presenting the issues concerning Real Time graphics. Finally possible future developments in the areas of Virtual Reality technology and Virtual Environments will be presented.

Interactive Volume-Based Indirect Illumination of Dynamic Scenes

In this paper we present a novel real-time algorithmto compute the global illumination of dynamic scenes with arbitrarily complex dynamic illumination. We use a virtual point light (VPL) illumination model on the volume representation of the scene. Unlike other dynamic VPL-based real-time approaches, our method handles occlusion (shadowing and masking) caused by the interference of geometry and is able to estimate diffuse inter-reflections from multiple light bounces.

Two Simple Single-pass GPU methods for Multi-channel Surface Voxelization of Dynamic Scenes

An increasing number of rendering and geometry processing algorithms relies on volume data to calculate anything from effects like smoke/fluid simulations, visibility information or global illumination effects. We present two real-time and simple-to-implement novel surface voxelization algorithms and a volume data caching structure, the Volume Buffer, which encapsulates functionality, storage and access similar to a frame buffer object, but for threedimensional scalar data. The Volume Buffer can rasterize primitives in 3d space and accumulate up to 1024 bits of arbitrary data per voxel, as required by the specific application. The strength of our methods is the simplicity of the implementation resulting in fast computation times and very easy integration with existing frameworks and rendering engines.