The use of computer graphics and virtual reality for visual impact assessments
Changes to the visual character of the landscape can become a key issue capable of influencing the outcome of an Environmental Impact Assessment (EIA). These changes are commonly referred to as visual impact, and it is recognised, unlike many other aspects of EIAs, that Visual Impact Assessment (VIA) relies less upon measurement than upon experience and judgement (IEATLI, 1995). Currently, there are very few quantitative techniques for the evaluation of visibility and it is mostly assessed qualitatively since it is concerned with the human appreciation of the landscape (Zewe and Koglin, 1995 and Wherrett, 2002). The main problem with qualitative techniques in assessing visual impact is that they may lead to bias due to their inherent subjectivity, hence there is a need for a more structured and consistent approach towards VIA. To reduce the subjectivity currently associated with VIAs, new quantitative techniques have been developed and existing spatial and qualitative techniques have been improved upon. The techniques developed in this research use Computer Graphics (CG) technology, including the field of Virtual Reality (VR). A quantitative method to calculate percentage view change has been developed that allows the accurate determination of the variation in any view, caused by an existing or proposed development. The method uses three dimensional (3D) CG models of an environment and software that has been developed using a scripting language from a 3D modelling software package. A new method has also been developed to create Fields of Visual Influence (FVIs) using standard 3D modelling techniques. The method improves upon the accuracy and efficiency of existing FVI techniques. A novel VR simulation technique has also been developed that attempts to reduce the subjectivity associated with simulations, by integrating quantitative and spatial techniques.