VIRTUAL CITY III/V
(Abstract of the 1997 Project)
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WEBTERMINAL
 The Task
An upcoming task for the community will be the paying of attention to the technological abilities of their members. In the Information Age it is not affordable anymore to keep isolated and to restrict access to information as China, Saudi Arabia and also Germany prefer. These ways cause a backwarded class system of information, separating between the Have all and the Know Nothing. But in opposite to other distribution troubles, there is no way to reach the Upper Class anyway, because exactly the knowledge to upgrade is hidden and forbidden. This is violating the general understanding of human rights and equality and surpresses the social moreover technological evolution of such a community and will decrease their market chances in international competition.
A fitting and right answer would be an introduction of low level entrance or channeling system to such technologies with a free of charge system to reduce the technological and emotional barrier (as local calls and for that reason also the Internet in the U.S., free telephone service within Sweden or free fax, voice and email as demonstrated with the now closed Tobit Web server), could be considered as an invitation to the interested parties.
The Polis
A growing number of such highly motivated participants leads, as seen in several Chat rooms, newsgroups or mailing lists, to a higher quality of information and communication structure.
This new dispute on the Polis, the Marktplatz could install, if supported by administration and government, a new kind or quality of Cyberdemocracy. This incarnation of a direct and original form of representation shows a great advantage to other structuring forms, because of the fact that technical filter and distance formal factors as skin, age, social and cultural heritage are playing only a small role at all. The progress for female, olds and outsiders is underlined especially in research programs and gives the chance to reinforce and to refresh the social unity.
The Features
To portray the progress, a continual preview of the transformations could be very useful, a real WebTerminal could provide there best results as a technical mirror or supervisor. If expanded to a hyper weather or traffic station, bulletin or message board, administrative helper or knowledge base, a suburban communication step will be gone.
This includes the standard figures featured by a free telephone, library, support hotline or emergency call, panorama view up to a city information system, video telephone or email account (as offered for The digitale Stad Amsterdam  by XS4ALL, or by the finally closed Internationale Stadt Berlin ) up to a declined homebase of the virtual nomads of this century.
COMPLEXITY
Data Reduction
As the majority of the (three dimensional VRML) examples in the net indicate that these worlds are still to complicated to handle. The huge amount of data and a convincing and fascinating presentation is, besides of the later discussed connectivity rates, dependent from three dimensional computing power. Momentary the browsers can give us only a graphical preview, but there is a hope because of the dramatical improvements of rendering power of the second generation of 3D graphics boards, the introduction of AGP, the installation of new and effective graphic standards as OpenGL and nurbs modeler and further optimization of (three dimensional) browser.
At the moment, VRML worlds have to be produced very careful to fulfill their prophecies of more usual or natural by visual reception. There exist four different but combinable ways or levels.
Obviously should complex worlds or systems be created as a result of a well thought process, to reduce the complexity unnecessary items should not appear or should be eliminated just on this first level, only determined or important objects and attributes should be selected. The level of reality depends therefore on the weight and importance of these objects.
This process will be continued at the second part. At this level worlds or objects will be separated and organized in modular structures, that allow to concentrate the presentation on special points and regions. All objects, surfaces or planes should be replaced by surfaces or planes with lowest accurate complexity or geometrical resolution, for instance by reducing of superfluous parts, subdivisions, key points or by using of instant copies and references.
At the third level, complexity and also computing time will be reduced dependent from view and rendering process. That means that only objects in viewing destination and area, situated between front and back clipping plane and not hidden by other objects are chosen and calculated. They will be portrayed, dependent on rendering process as for instance raycasting, raytracing or radiosity, viewer and browser preferences and object parameters. The proximity sensor or level of detail (LOD) allows it to select objects on different attributes such as distance to render shadows, textures, colors, animation's, reflections and transparency and so on.
At last the result will be filtered by mathematical compression methods. There exist different solutions as transformations from ASCII in shorter binary formats of uncountable compression algorithms, but in the computing sciences '.zip' in its different dialects as gzip, winzip or pkzip is the de facto standard. Through all this laborious operations the level of complexity can be reduced up to 1/1000 of its original size, dependent on project and without (feelable) quality losses.
RENDERING
Raytracing
A technique used in computer graphics to create realistic images by calculating the paths taken by rays of light entering the observer's eye at different angles. The paths are traced backwards from the viewpoint, through a point (a pixel) in the image plane until they hit some object in the scene or go off to infinity. Objects are modeled as collections of abutting surfaces which may be rectangles, triangles (polygons) or more complicated shapes such as 3D splines (nurbs). The optical properties of different surfaces (color, reflectance, transmitance, refraction, texture) also affect how it will contribute to the color and brightness of the ray. The position, color and brightness of light sources, including ambient lighting, is also taken into account.
Raytracing is a powerful rendering technique, but has a number of major drawbacks. It is view dependent - rendering with different viewpoints must be redone entirely. Its simulation of diffuse reflection effects is very poor. Simulation of aerial light sources is very difficult.
Radiosity
Radiosity addresses these problems by rendering using heat transfer principles. As in finite-element calculations, the scene surfaces are discretized to n elements (patches). A radiosity bi is associated with each patch Pi (polygons). This is the amount of energy emitted by a unit area of the element. The energy transfer between two elements is fully characterized by their relative position and orientations, their physical characteristics and occluding objects. The proportion of the total energy emitted by element Pj, received by element Pj is the form-factor Fjj. When calculating form factors, we assume that surfaces are Lambertian or ideally diffuse, i.e. each point on the surface emits energy uniformly in all directions.
The input for the radiosity calculation is the specification of a set of n patches. The radiosities are computed by computing n2 form factors and solving a set of n linear equations. After obtaining radiosity values for the patches, the scene can be rendered from an arbitrary viewpoint by simple shading methods.
This classic radiosity method suffers from two major drawbacks: It is inefficient in space and time because formfactors are computed and stored even for elements that are not illuminated. The radiosity value is assumed to be uniform over the patch, which is generally incorrect.
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