GENERATION OF DIGITAL SURFACE MODELS 
FOR ARCHITECTURAL APPLICATIONS WITH ARCHIMEDES3D 
Rüdiger Tauch and Albert Wiedemann * 
FPK Ingenieur GmbH, Feurigstr. 54, D-10827 Berlin, Germany — { R.Tauch, A.Wiedemann} @fpk.de 
Commission V, Working Group V/4 
KEY WORDS: Surveying, Digital Photogrammetry, Architecture, Digital Surface Model, Orthoimage 
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ABSTRACT: 
Orthoimages are well suited for architectural documentation. The most challenging part of their generation is the determination of 
the Digital Surface Model (DSM). There are some different techniques available to acquire the information requested to generate a 
DSM. In this paper we describe how a motorized and reflectorless total station, controlled by the software package Archimedes3D 
can be used to determine the necessary information. Besides the total station, only a mobile computer and a digital camera are 
required to acquire the data for the differential rectification. The lower data rate of a total station compared to laser scanners can be 
compensated by maintaining intelligent control of the measurement process. 
KURZFASSUNG: 
Orthophotos eignen sich für die Dokumentation von Fassaden. Dabei ist der aufwändigste Teil die Bereitstellung des Digitalen 
Oberflächenmodells. Es gibt unterschiedliche Techniken die erforderlichen Daten zu erfassen. In diesem Aufsatz wird beschrieben, 
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wie dies mit einer motorisierten, reflektorlos messenden Totalstation unter Steuerung durch das Programm Archimedes3D erfolgt. 
Neben der Totaltstation wird nur ein mobiler Computer und eine Digitale Kamera benótigt um die für das Orthophoto erforderlichen 
Daten zu erfassen. Die geringere Messgeschwindigkeit der Totalstation wird durch einen intelligenten Messprozess kompensiert. 
1. MOTIVATION 
Archimedes3D is a system for the integration of different 
measurement types in the field of architectural documentation. 
One of the core products is the Digital Orthoimage, a product 
combining the geometry of a plan with the information density 
of a photo (Hemmleb & Wiedemann 1997, Dequal & Lingua 
2002). Archimedes3D is a modular tool box. One of the tools is 
FASED (Façade Digital Surface Model Editor), a tool to 
combine geodetic and photogrammetric data, laser scanner 
point clouds and/or manual measurements in an integrated 
environment to provide the necessary Digital Surface Model 
(DSM, depth map) for the generation of true orthoimages of 
facades. 
Data can be introduced in the form of single points, profiles, 
point clouds or CAD models. suited than a triangle network: 
Most of the edges of the object are parallel to the vertical and 
horizontal grid lines of the DSM and most faces are rectangular. 
Due to the different planar facade elements of the common 
objects surface, a triangle network would consist of very 
different sized coplanar and perpendicular triangles. 
The DSM describes the orthogonal height of the facade points 
above an analytical surface, usually a vertical plain. For 
architectural applications a rectangular grid seems to be better 
Thresholds for the optimized triangulation are difficult to find. 
In a regular grid, you only have to determine a suitable grid 
width for the DSM, based on the resolution for the proposed 
  
* 
Corresponding author. 
orthoimage. If the available input data have already a sufficient 
point density, e.g. based on laser scanner data, only the closing 
of occluded gaps remains as a challenging tasks (Wehr & 
Wiedemann 1999). Bot all laser scanner systems provide the 
required data in a sufficient quality and density (Bóhler et al., 
2003) Some gaps might be closed by an image based 3D 
acquisition (Schouteden 2002) — but special problems of 
  
Fig. 1: Measurement equipment for FAMES 
   
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