Last update, Sept. 18, 2001

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Publications on Cyber Monument applications :

• Images for Accelerating Architectural Walkthroughs, by Anselmo Lastra et al., 1998.

Publications on Cyber City applications :

• Procedural modeling of cities, SIGGRAPH'01, Parish, Y.I.H. et al., 2001.

Publications on both CyberCity & CyberMonument :

• Applications of Virtual Reality: CyberMonument & CyberCity. Leymarie. F. & Gruber, M., 1997.

BibTeX references .

The authors accelerate architectural walkthroughs by replacing 3D geometry seen through doors and windows with images.

We are investigating methods to accelerate rendering of architectural walkthroughs. In this article, we improve upon a cells and portals framework by using images to replace geometry visible through portals (doors and windows) in a three-dimensional model. We present several solutions:

• images texture-mapped onto the portal,
• 3D warping of single reference images, and
• 3D warping of Layered Depth Images (LDI).

We have achieved significant speedups and present the results of applying the techniques to large architectural models.

Keywords: interactive geometry, images, cells, portals, image-based rendering, 3D image warping, layered depth images.

Weblink @ ETH, Zurich

Modeling a city poses a number of problems to computer graphics. Every urban area has a transportation network that follows population and environmental influences, and often a superimposed pattern plan. The buildings appearances follow historical, aesthetic and statutory rules. To create a virtual city, a roadmap has to be designed and a large number of buildings need to be generated. We propose a system using a procedural approach based on L-systems to model cities. From various image maps given as input, such as land-water boundaries and population density, our system generates a system of highways and streets, divides the land into lots, and creates the appropriate geometry for the buildings on the respective allotments. For the creation of a city street map, L-systems have been extended with methods that allow the consideration of global goals and local constraints and reduce the complexity of the production rules. An L-system that generates geometry and a texturing system based on texture elements and procedural methods compose the buildings.

Weblink

The part of the world population living in cities keeps growing. Within the next 20 years, it is expected that more than 50% of the people will live in densely populated urban areas (close to 75% in industrialised countries). The associated continuous growth of the « built environment » (buildings, houses, road and energy networks, transit systems, etc.) should benefit from new Information Technologies (IT) and in particular Virtual and Augmented Realities, i.e., the making of virtual 3D spaces and objects that mimics or complement reality as we normally apprehend it through our sense of vision. Such virtual scenery shall permit to better plan, design, engineer and deliver the needed evolutions of the built environment. Noticeably, the present day economical impact of construction of the built environment is formidable: it represents close to half of the capital investment in most of the Member States of the European Union.

The 3D digital reconstruction of the built environment will benefit from advances made in the (semi-)automatic exploitation of image data (such as aerial and ground-based video recordings). Such imagery can be used not solely to recover the geometry of the built environment but also the (photo-)textures of the surfaces making this scenery. The realistic and faithful 3D models thus recovered will find application in diverse fields such as architecture, urban planning, video games and simulators. Furthermore, once this correspondence between geometry and photometry is established, the modelling can be made even more sophisticated by recovering material properties such as electromagnetic reflectance functions. This shall open-up the door to applications in fields such as cellular phone communication planning in urban areas, or illumination modelling of buildings.

In this presentation we will discuss potential applications of virtual reality via the introduction of two complementary interactive multimedia information systems we call CyberMonument and CyberCity:

• A CyberMonument provides access and use of tools for authoring and distributing multi-dimensional and multimedia databases of interiors and exteriors of (famous) architectural sites such as historical buildings, monuments, cathedrals, etc.
• A CyberCity provides authoring and database management tools for photo-realistic visits and tele-use of large and complex 3D urban multimedia databases in a pan-European telematics context.

The new IT required to produce CyberMonuments and CyberCities are now being developed by leaders of the industry and academic worlds. We have already achieved some prototype demonstrations which we illustrate in this paper. The application of such new tools in the context of VR or AR shall permit in particular to better tackle the growing complexities of urban planning in the European metropolis of tomorrow.

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Page created & maintained by Frederic Leymarie, 1998-2001.
Comments, suggestions, etc., mail to: leymarie@lems.brown.edu