REQUIREMENTS FOR PHOTOREALISTIC 3D MODELLING OF URBAN AREAS 
Michael Gruber, Franz Leberl and Markus Maresch 
Institute for Computer Graphics 
Graz University of Technology 
Münzgrabenstr. 11, A-8010 Graz, Austria 
ISPRS IWG IIVIV 
Key Words: 3D Urban Database, 3D GIS, 3D Modelling, Photorealism 
Abstrac: 
  
The creation of photorealistic 3-D digital models of urban areas is based on several source 
data, different techniques to acquire, refine and maintain these data and powerful 
computersystems, which allow to perform the required operations. The current contribution 
describes the most important requirements for the complete modelling of urban areas and the 
use and maintainance of these data. We therefore show the concept of a digital workstation, 
which combines the functionality of several well known elements like photogrammetric image 
set up or digital texture mapping and the concept of a geo-server which will guarantee remote 
and local acess to these data with acceptable performance. 
  
Kurzfassung 
Dreidimensionale digitale  Stadtmodelle nehmen einen immer breiteren Raum in 
unterschiedlichsten Bereichen wie Stadtplanung, zivile Sicherheit, mobile Telekom-munikation 
oder Unterhaltung, Informations- und Bildungswesen ein. Trotz einer sich stark entwickelnden 
Computer- und Datenübertragungstechnologie sind eher Fallstudien und kleinráumige Projekte 
vorherrschend, für ^ photorealistische Darstellungen | ganzer Städte stellen sowohl die 
Datenerfassung wie die Verarbeitung und Visualisierung der anfallenden Datenmengen eine 
^ nach wie vor schwierige Aufgabe dar. Wir gehen nun davon aus, daß ein Gesamtsystem zur 
Erfassung, Verwaltung und Übertragung der Stadtmodelldaten konzipiert werden muß. Dieses 
Gesamtsystem wird im folgenden beschrieben. 
  
Introduction and thematic information, generated at low cost 
and accessible at high speed by a broad range of 
We present a progress report of our current work local or remote end-users. 
to create, maintain and prepare for remote and 
local use fully threedimensional photorealistic Such 3-D data will not only present the geometric 
textured digital models of cities. These 3-D relationships in a city, but also permit to create 
Cityscapes are currently a widely discussed photo-realistic renderings for various decision- 
upgrade from strictly twodimensional geographic making and planning tasks and will involve into 
information systems (GISs) [Fórstner et al. 1993]. various new applications like civil security, 
Data sources for the 3-D city model of course transport, leisure and entertainment, education 
include the existing GIS, the aerial photographs, and training, tourism, publishing, etc. (cf. Fig. 1). 
which are periodically produced on behalf of the 
citie's authorities and photographs taken from 
street level in order to cover facades of a citie's 
buildings [Gruber et al. 1995a]. In addition to the 
GIS data and aerial and terrestrial images we are 
involving the DEM of the terrain, which represents 
the shape of the bald earth. Each data set 
consists of different types of data, needs different 
amounts of disk storage and has to be prepared 
ton. and tuned for the requirements of the user. These 
efforts shall result in a complete 3-D database of 
urban areas. In addition the concept of this 
information system will be subsumed into a 
multimedia system. The goal is to take advantage 
of the emerging information and telecom- 
munication technologies to create a large market 
for 3D urban data bases with geometric 
   
Fig. 1: Part of photorealistically rendered scene of 
a city block in Vienna 
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International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B3. Vienna 1996