MANAGEMENT OF URBAN SPACES AND SERVICES BY VR (VIRTUAL REALITY) SYSTEMS IN HELSINKI - A LARGE SCALE EXPERIMENTAL R&D PROJECT FOR EUROPEAN CULTURAL CAPITAL 2000
ABSTRACT. It has become possible and economically feasible to build public telecommunications networks that enable near tv-quality transmission to and from households and other places and services connected to the network. It is also becoming feasible to model whole cities in 3D models with standard modelling languages. These models can be used for navigating the urban space and services. Fully automatic modelling techniques were not found useful because these models get much of their familiarness from little details while other details are not necessary from the user point of view. The modelling elements and techniques were found to resemble charicature drawing where one tries to get as much familiarity as possible with as few lines as possible. Present internet standard 3D VRML-viewers were found to be lacking some critical features but are expected soon to meet the requirements.
1. Urban data and telecommunications infrastructure
Management of urban spaces and services requires a very sophisticated and practical infrastructure. This infrastructure is more and more abstract and centered towards data manipulation or transmission. Management requires much data collecting, processing and viewing. Many of todays services are also data or telecommunications bound.
Since much of the data and services are related to geographic co-ordinates we should consider modelling the information and services as a virtual reality model if this could be accomplished easily enough. Through this virtual reality we should then navigate to get in contact with the GIS-information sensors, services and other GIS-data.
Virtual reality is not a well defined subject. The term has been used to describe visualisations for different simulation models, user interfaces for various geographic information systems, computer aided manufacturing systems, architect models and newest generation of computer games. One of the first large scale users for virtual reality have been airlines for teaching the pilots to fly new aeroplane types.
Internet has popularized a language for describing three dimensional models. This language is most often called VRML (Virtual Reality Modelling Language) [1]. VRML-model can be layered and it can include links to other models or other elements of internet content.
Common spesification for VRML has been accepted by nearly all members of the software industry. Current finalized spesification is VRML 2.0. This version includes features like videotextures mapped over flat or spherical surfaces, voice backgrounds and many other spesifics that help in creating realistic and versatile three dimensional models for various purposes.
Several industry participants have created their own tools for viewing VRML-models including IBM, Sun, Microsoft and Netscape. These viewers are usually distributed freely and can be used in conjunction with popular other internet viewers such as Netscape Navigator or Microsoft Internet Explorer. Few viewer developers have created enhancements so that users are represented by animated avatars and can interact with other users of the same model. One excample of these is Worlds Away by Fujitsu.
2. Telepresence and video communication
Networked virtual model can be used for telepresence where the viewers are connected to one or two way video communication. Besides video transmission telepresence can also be achieved by animated avatars as mentioned earlier. Avatars can be easily implemented as three dimensional but facial impressions and other natural characteristics are more difficult to implement.
128 Kb/s badwidth supplied by ISDN is commonly used in professional video conferencing and can thus be considered satisfactory for such purposes. Analog modem lines with 28.8 Kb/s capacity have also been used by hobbyists. Many manufacturers are expected to include video conferencing capability to high end home computers that come to market for Christmas season 1996. Video codecs to these are software based and require 200 MHz Pentium processors for intended quality.
Field trials by Helsinki Telephone show that users are very satisfied with picture quality using 2 Mb/s MPEG1 transmission [2]. Picture quality has been felt better to that of regular video tapes (VHS) when movement is slow and equal in fast moving, slightly depending on the type of content.
Field trials by Helsinki Telephone showed also that 2 Mb/s transmission can be achieved easily to nearly all Helsinki Telephone customers using regular copper lines from user houshold to the telephone switch and from there onwards using ATM-network [3]. ADSL-technology gives one way broad band connection. Using symmetrical SDSL or HDSL technologies users can achieve two-way broad band communication using regular copper pairs. This two way capability is required if the user needs to transmit high quality video in addition to receiving it. Prices of these new transmission systems are decreasing rapidly and can be estimated to reach mass market levels by the end of 1998, at latest.
3. Helsinki Arena 2000 -project
Helsinki Telephone Company and the City of Helsinki have started a project to create a three dimensional model of the city and its surroundings. This VRML-model will be used as the user interface for local electronic services such as video commerce, multipoint video telephony, cultural services, other public services, entertainment, virtual meetings, video telephony and viewing the city and its public places in real time. The project has gathered wide support including all seven regional art and science universities, largest edp-companies and other large corporates.
Virtual Helsinki will be networked virtual reality where users can interact. The project is based on internet standards but internet itself has to be locally enhanced to facilitate acceptable quality for virtual reality and multimedia content and interaction. Internet by itself has no means to guarantee either response time or bandwidth and thus quality of real time video telephony or audio interaction is not acceptable without enhancements. Users need to connect directly to Helsinki Arena 2000 or through other means which guarantee the bandwidth outside Helsinki Arena 2000 -network.
The Helsinki Arena 2000 -network will be a combination of fiber and copper lines. Home and small office users are connected via access lines starting from 128 kb/s ISDN-lines up to 2 Mb/s HDSL-lines to the nearest telephone switch. Telephone switches are connected to each other with fiber based ATM- and SDH-lines. Service providers, gateway providers to other networks and corporate users are connected with ATM-lines. For each personal user an ATM-connection to the service provider’s system is created thus ensuring required bandwidth and other QoS elements for each user in spite of the TCP/IP-protocol used for internet compatibility.
Virtual Helsinki VRML-model will be copied to each access switch. User can navigate the model and activate links which connect him to service providers equipment or other users PC:s and regular telephone conversations. The model is distributed so that only external model of the city and limited amount of video streams viewing the public places of the city are provided from the centrally operated servers. Each service provider or individual supplies the necessary models when user gets inside their buildings. No constraints are enforced for the interior models an so they follow industry standards or be very experimental and require special software from the user.
4. First results from project experiments
The project is in its starting phase but initial feasibility studies have yielded some results already in many project areas.
Based on expected decrease in transmission equipment we have calculated that 2 Mb/s connections can be provided to households before year 2000 at reasonable costs. Based on expected increase in processing power and video capabilities we expect that ISDN-level video conferencing equipment will be commonplace and near tv-quality receiving will be possible with equipment in household affordable prices. Based on world wide software investments and market behaviour we expect that VRML and its PC-based viewers will be developed into efficient and suitable tools for modelling virtual worlds and meeting points.
Our first experiments show that there are many architect tools suitable for modelling a virtual city. Fully automatic means such as stereo photography have been ruled out for other than information gathering purposes. There is a need to minimize information content in the model and at present this requires human desicion making in each typical picture element. There must be minimum amount of information with maximum amount of familiarness. This actually requires artists and is very close to charicature drawings which draw their strength from human psychology and pattern recognition. It seems that this work can be automized by component libraries whitch then are manually selected but not otherwise.
Thus we place the buildings in the correct coordinates but use object based libraries for wall and windows types, rooftops, trees, pillars etc. Only specific landmarks are individually modelled from more primitive objects. Autocad and Lisp based city planning software KCAD from Arcus Software (Finland, http://www.xgw.fi/biz/arcussoft/english) is used in the modelling phase. Telephone numbers and other GIS (Geographic Information System) linking information is then included into the building objects. A specific Lisp program is then used to convert the object model into a VRML-model.
A first test model covers about one square kilometer from the city centre. It can be found in the adress http:\\www.hpy.fi\arena\demonstraatiot. This model is 1.5 Megabytes and preparing it took about one manmonth of time. Buildings are in correct co-ordinates (10-20cm X and 0.5-1m Y) and they have very good familiarness. This shows that modelling need not be very expensive when the right tools are found.
Present VRML-viewers are early versions and don´t support all features required by the spesifications. Especially important is LOD-feature which means that models are saved in several levels of detail and the further the objects are the lower level of details one gets. To get a complete city modell to work in PC:s we need this fixed in the viewers and many other speed and efficiency enhancements in both PC:s, their peripherals, system software and VRML viewers. These enhancements combined are expected to yield efficiency gains in the order of two or three magnitudes by the year 2000 which would make Virtual Helsinki a pleasant environment even for the home PC-users.