Virtual Reality and Graphics Engines

An Automated Modeling Method for Multiple Detail Levels of Real-time Trees

C. Koniaris, A. Gaitatzes, G. Papaioannou, Proc. IEEE Int. conf. Games and Virtual Worlds for Serious Applications, pp.53-60, 2009.

Abstract. Rendering realistic outdoor scenes in realtime applications is a difficult task to accomplish since the geometric complexity of the objects, and most notably of trees, is too high for current hardware to handle efficiently in large amounts. Our method generates trees with self-similarity, and later exploits this property by heavily sharing prerendered textures of similar parts of the tree. The intrinsic tree hierarchy of the trees, combined with their self-similarity, allows generation of multiple levels of detail. Here we present the flow of the processing stage, from the collection of the required input data until the export of the models in all their levels of detail as well as related and additional data.

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Designing a Real-time Playback System for a Dome Theater

D. Christopoulos, A. Gaitatzes, G. Papaioannou, G. Zyba, Proc. Eurographics 7th International Symposium on Virtual Reality, Archaeology and Intelligent Cultural Heritage (VAST), pp. 35-40, 2006.

Abstract. Designing a Real-time Playback System for a Dome TheaterMost dome display systems today employ pre-rendered shows for attracting visitors. In addition since the technology is well established, developers have many tools at their disposal for creating such shows. On the contrary real-time shows for dome displays are just starting to appear. As a result the production of such shows is not a standardized process. Slowly, progress is made. Graphics generator cards are able to support the required SXGA+ resolutions and the supporting cluster systems are able to supply the processing power and memory bandwidth that such real-time systems require. Tools have to be developed and new processes have to be established. The Foundation of the Hellenic World (FHW) having produced numerous real-time productions for immersive flat display systems has great experience in realizing such shows. In this paper we present the technological developments for the production of real time applications for digital dome display systems.

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Media Productions for a Dome Display System

A. Gaitatzes, G. Papaioannou, D. Christopoulos, G. Zyba, Proc. ACM Symposium on Virtual Reality Software and Technology (VRST) 2006, pp. 261-264, 2006.

Abstract. 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.

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Efficient Occlusion Culling using Solid Occluders

G. Papaioannou, A. Gaitatzes, D. Christopoulos, Proc. 14th International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision (WSCG '2006), pp. 85-93, 2006.

Abstract. Occlusion culling is a genre of algorithms for rapidly eliminating portions of three-dimensional geometry hidden behind other, visible objects prior to passing them to the rendering pipeline. In this paper, an extension to the popular shadow frustum culling algorithm is presented, which takes into account the fact that many planar occluders can be grouped into compound convex solids, which in turn can provide fewer and larger culling frusta and therefore more efficient elimination of hidden geometry. The proposed method combines planar and solid occluders using a unified selection approach and has been tested on a commercially deployed virtual reality system.

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The Ancient Olympic Games: Being Part of the Experience

A. Gaitatzes, D. Christopoulos, G. Papaioannou, Proc. Eurographics 5th International Symposium on Virtual Reality, Archaeology and Intelligent Cultural Heritage (VAST), pp. 19-28, 2004.

Abstract. 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.

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Enhancing Virtual Walkthroughs of Archaeological Sites

G. Papaioannou, A. Gaitatzes, D. Christopoulos, , Proc. Eurographics 4th International Symposium on Virtual Reality, Archaeology and Intelligent Cultural Heritage (VAST), pp. 175-184, 2003.

Abstract. 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.

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Reconfigurable Virtual Devices for Multiplayer Virtual Reality Shows

G. Papaioannou, D. Christopoulos, 2007.

Abstract. In many VR installations, multiple users can interact with the virtual reality world through a vast variety of commercial or custom input controllers. In some cases, even auditorium seats are equiped with input devices such as joysticks, buttons or jog dials. The following report discusses a practical virtual device abstraction layer for the real-time remapping and weighting of auditorium controls according to the show reqiurements.

Links: Virtual devices mapper technical overview

High-performance Professional-quality Positional Audio Server (Impulse)

G. Papaioannou, 2006.

Abstract. The Impulse sound server was built to reproduce 96KHz low-noise 64-voice output to drive the high power THX-class speaker system of the THOLOS VR auditorium of the Foundation of Hellenic World. It runs separately from the visualization side of the VR software and communicates with main application via message passing, thus providing complete abstraction, remote execution, replication and low latency.

Links: Impulse sound server technical overview

Reconfigurable, Tiled Multi-display Projection System (TiDE)

G. Papaioannou, 2005.

Abstract. In many virtual reality installations and applications the need arises for the projection of synthetic imagery on multiple surfaces, or on non-planar or discontinuous surfaces, as is the case with a CAVE system or a dome. This brief report discusses the implementation of an abstraction layer for mapping physical display areas (tiles) onto viewing frusta and how stereoscopic rendering can be adapted to such a diverse setup.

Links: TiDE technical overview

Large Scale Virtual Reality Cluster Design

G. Papaioannou, A. Gaitatzes, G. Zyba, 2005.

Abstract. Large multi-display systems such as stereoscopic panoramic displays or dome theaters require the distributed and precisely sychronized rendering of individual image blocks, using a computing cluster. The following report presents the architectural decisions and design issues related to the practical implementation of the 24-node VR cluster of the Foundation of the Hellenic World.

Links: FHW dome theater cluster technical overview