Communication during the design process has a substantial role because; it exchanges messages and conveys ideas to people with different skills and interests. Also, the development of high quality 3D modelling, photo rendering and VR software has shifted the way we communicate architecture, from a conventional one to a digital format and so, provided us with another way for the communication of information, the visualisation of processes and the creative expression of ideas. This paper investigates the impact that Immersive Virtual Reality technology can have on visualisation of a design review scenario in construction, which was developed during the course of the European CoSpaces project and the potential of such technologies to alter the way enterprises work.

The development of a maintenance programme for construction projects is a highly complex and data intensive undertaking. This exercise is characterised by the lack of relevant data on the one hand and the overwhelming amount of irrelevant data on the other. This is partly due to the existence of numerous events which act upon the building and that all buildings contain many components, each with several varieties. The complexity of the process is exacerbated by the fact that the interaction between the events and building components extends over the lifetime of the project. The uncertainties and complexities have resulted in increased conservatism in the development of life cycle evaluation of building performance and maintenance programme development. Subsequently, almost all maintenance programmes tend to display the symptoms of one or both of the following pitfalls: maintenance actions are too early, thus uneconomical; and maintenance actions are too late, thus compromising the quality of service. The current research project is based on the premise that the visual approach to maintenance programme development offers a viable solution to the above pitfalls. However, the retrospective nature of the problem suggests that the only practical visual approach is one which relies on the use of virtual simulation of the building. Therefore the aim of the broader research is to develop a 4D visual model of building degradation through time. The focus is on building flooring systems.

Any negotiation involves consideration of several variables which act independently and collectively to determine the configuration of alternative outcomes. The numerical analysis of alternative options can be a tedious and lengthy exercise, thus inhibiting the negotiator from making informed decisions and indeed achieving the optimum benefit. Construction project financial management is an example where all related variables are up for negotiation between the main parities: the client, contractor and sub-contractors. This paper builds on the works previously introduced at IV conferences where the potential of the visual approach to the analysis of growth patterns was illustrated and the respective mathematical expressions were introduced. The paper collates these works into a conclusive visual method for instantaneous analysis of several variables that are influential in configuring construction project finance, thus preparing the contractor for informed negotiation with other parties.

It has been previously shown that the visual approach to the analysis of the behaviour of growth patterns can provide a viable solution to the understanding of the physical behaviour of the subject matter. Also, it has been demonstrated that the shape of the profile can be defined in terms of a number of characteristics some of which are general for all profiles and others are specific to individual circumstances. These characteristics, referred to as shape-parameters, are used for the analysis of the profile. Also, they are used for construction of the profile that the phenomenon is likely to assume. The method was validated by applying it to construction project expenditure pattern forecasting and further validation was undertaken by the use of statistical technique, namely, principal component analysis. In this paper, the mathematics of the model is represented whereby, for a given set of shape-parameters, the precise profile is mathematically generated. Due to its complex nature, the problem is decomposed into separate modules each satisfying a number of requirements. The modules operate independently but when combined, the overall boundary requirements are also satisfied.

There are many qualitative and quantitative techniques which have been used for a variety of cases of curve fitting, smoothing and forecasting. All but a few have considered curves from a shape-geometry point of view. The paper argues that curve geometry contains characteristics that are descriptive of the nature of the subject area and therefore provides a viable alternative for the generation of a forecast. In spite of its importance for the success and survival of construction contracting companies, cash flow forecasting and management hasn't been extensively studied by researchers or practitioners. The increased research activity in this field during the 1980s failed to result in the development of a universally accepted alternative to the traditional method of time-related elemental cost build-up. Many of these attempts sought to develop a viable alternative by focusing on mathematical approaches. The non-mathematical approaches to forecasting expenditure flow of construction projects offer a clear explanation as to the origin and nature of the resulting forecast, whereas the mathematical approach to forecasting has the advantage of being simple, cheap and fast. These, mutually exclusive features of the different approaches to model development have lead this work to investigate the possibility of developing a mechanism for mathematical models to facilitate some degree of understanding about the behaviour of project expenditure profile and hence overcome the black-box nature of the mathematical solutions.

The visualisation of an object, such as a building, 'in time'-viewing it from different perspectives-has been the subject of many research and development efforts, and significant inroads have been made in this area, which is supported by a sophisticated software technology. On the other hand, visualisation of a building 'though time'-viewing it as it ages or gets younger-has received little attention. In a previous publication by the authors (Proc. Int. Conf. on Inform. Visualisation, London, England, 27-29 Aug. 1997), this concept was introduced and applied to the building maintenance programme. The overall process was modelled and generalised, and lighting, paints and carpets were introduced as examples where the research work can be applied. This paper concentrates on the lighting system and determines the time-related behaviour of different light sources under the impact of intrinsic and environmental factors. This process is modelled and expressed in a mathematical form which facilitates its visualisation through the use of VRML.

The use of 3D visualisation has long been established as a major breakthrough in closing the gap between a client's need and what is perceived by the designer to be the need of the client. Nevertheless, construction clients are increasingly demanding a greater participation in the process of design generation. This has been a welcome move by all parties, as less variation means less conflict. In spite of its vast practical uses, in the field of visualisation, the ability to travel through time is an area that has been neglected by the academics and the developers alike. The paper highlights the benefits of the incorporation of the 4/sup th/ dimension-the time dimension-into 3D visualisation. Building maintenance is used as a case study to demonstrate the practicality of the 4D visualisation and its representation through VRML. To this end, the focus is on the lighting, paints and carpets. However, the concept can easily be expanded to encompass the causes and effects of all events on all building components.