eres2010_130_Henneberry_MODELLING_THE_RELATI(5)

The paper describes the development and application of physical-financialmodelling techniques to the analysis of relations between development design –covering the broad characteristics of a scheme, such as land use mix, developmentdensity and built form – and financial viability. It is divided into two parts

Developing Visualization Techniques and Links to Financial Appraisals

In this research, 3D models of areas of the River Don corridor (and selected tributaries) in and around Sheffield are being developed so that, inter alia, proposed physical changes or ‘interventions’ may be visualized and then used as part of a sustainability assessment process. These models need to be viewable in real-time either as eye-level walkthroughs or as ‘birds-eye’ overviews and to be sufficiently representative of the actual areas and the interventions to allow stakeholders to assess the latter. The visualization system uses Simmetry3d software, a design and visualization solution based on the technologies used in the computer game industry. Simmetry3d is PC based and can also be connected to the Rave studio, a University of Sheffield virtual reality facility that supports stereoscopic three-dimensional viewing.

Models of the existing areas of Sheffield’s river corridors were constructed from various data sets and the steps in which they were combined were as follows:

A baseline terrain model was created, combining a Digital Elevation Model, (OS Land-form profile) and aerial photography, (Cities Revealed); then

Existing landform features were created from GIS vector data (OS Mastermap) by importing these data into Simmetry3d and applying its tools to them; then

Existing buildings were created from the GIS data (OS Mastermap) and photographic survey data were used to add facade textures; and finally

Interventions were introduced into the existing model either by editing the GIS vector data or by creating new models and importing these into the correct location in the existing model.

The models were linked to a financial appraisal system so that the financial implications of interventions could be assessed. The financial appraisal system already had a clearly defined data interface which required the areas of different land/building use categories to be assigned to it in order for it to compute its results (discussed in more detail in the subsequent section). In order to implement the link it was necessary to identify the requirements of the whole system and the workflow proposed for its use. Investigation revealed that such a system should be able to: Design a new site layout to the correct size and scale; Categorize design elements for financial appraisal; View the design in 3D and in real time; Analyse the design in terms of the areas of its constituent parts and communicate these on to a spreadsheet for financial appraisal;

Easily allow alterations to site layout, building heights and floor space uses so that the financial implications of such design changes may be calculated; and Be compatible with the real time visualization system.

Analysis showed that these requirements could be met through the use of a generic 3D CAD system, with the addition of a bespoke ‘plug-in’ to transfer the data produced by the analysis to the financial appraisal spreadsheet. Plug-ins are small sub-routines of software that may be written to control a larger software application and, as such, can provide tailored functionality to more generic software applications. By adopting this approach, modelling of a site could be done in isolation as a pre-process to the more detailed and labour intensive visualization work, providing a