Computer visualizations of planned built environment and infrastructures are increasingly used as a basis for democratic decisions when the impact of the projects is of wide-ranging interests and influence. It is of great importance for the democratic process that all aspects of the material in a project can be trusted as a basis for discussion and decisions among politicians and citizens. This paper describes the objective aspects of the quality of data in the information basis for 3D visualizations and it calculates the precision that can be achieved by the known methods of 3D-CAD visualization. Furthermore, the paper suggests a model that can secure sufficient quality in future visualization work processes by accumulating documentation for both the factual basic data and information that carry the aim and meaning of the message and make this information accessible through the visualization. 3Dvisualization Process Model Quality Control UffeLentz uffe.lentz@aarch.dk http://aarch.dk/arkitektskolen_aarhus/personale/persondata/uffe-lentz/ AndreasLykke-Olsen andreas.lykke-olesen@aarch.dk http://aarch.dk/arkitektskolen_aarhus/personale/persondata/andreas-lykke-olesen/ Arkitektskolen i Aarhus Institut for Design dk http://aarch.dk/institutter/institut_for_design/ 2004-09-152004-09-18 Copenhagen http://www.ecaade2004.dk/ 0954118324 CumInCAD Cumulative index of Computer Aided Architectural Design 2004 380-386 http://cumincad.scix.net/cgi-bin/works/Show?2004_380