Proceedings of The XXVIII IAHS World Congress of Housing “Challenges for the 21st century”, Abu Dhabi, United Arab Emirates, April 15-19, 2000, pp433-444
An integrated web-based virtual model to support housing projects
G. Aouad, M. Sun, N. Bakis, S. Birchall & W. Swan
Correspondence to: Prof Ghassan Aouad School of Construction & Property Management University of Salford Salford M7 9NU UK e-mail
[email protected]
Abstract
This paper describes an integrated web-based virtual model that is being developed at the University of Salford in the UK to support housing projects. The model supports the integration of design, cost estimating and time planning information using the concept of an integrated project database that is interfaced to a web-based virtual reality environment, to enhance the visualisation and sharing of information within housing projects. The model has been developed in response to user requirements and changes in market conditions. The data has been collected through a series of interactive workshops whereby the industrial organisations involved in the project have clearly articulated the system’s specifications for a better housing market. In the
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developed system, the user can perform what-if analysis which will allow the optimal design of a certain site to accommodate as many houses as possible. The system would then generate all the cost estimates and time plans which can be visualised in a webbased virtual reality environment. This will give potential customers/property purchasers the opportunity to remotely view any housing development, the configuration of the house and the cost associated with it, and in some instances perform some changes to specifications to assess time and cost implications. The system is now being validated by a housing firm in the UK and some feedback on this will be included in the paper. In addition, this paper will describe the conceptual modelling phase as well as the implementation issues associated with the integrated system. Finally, this paper presents some of the findings in benchmarking the types of benefits that could be attained from using such a system when compared with the conventional approach to housing developments.
Keywords: Process, Housing, Integration, VR, Web
Introduction
The housing industry in the UK and across the globe is facing many difficulties in terms of maintainability sustainability and buildability. The industry needs to develop and use innovative and creative technologies, be they construction or IT related, to overcome some of these problems. The need for modular buildings that are cheap to construct, run and maintain is of paramount importance. This paper addresses some of the state of the art IT technologies that could be used to enhance the performance of the housing market. This paper presents a web-based virtual model and its potential
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uses within the housing industry. The model is centred around a suite of integrated applications that communicate within a central model. The prototypes have been developed in C++ on the IBM PC. The integrated database supports the functions of design, estimating and planning by allowing these phases to effectively share information dynamically and intelligently. The system revolves around a central object-oriented information model. The information model contains a core which captures knowledge about the means of transferring information across domains involved in a housing project. All the models in the system are fully independent of specific applications, and each domain model provides support for general classes of a given application.
Many studies have been conducted in recent years recommending the use of integration and VR/3D technologies to simulate and model construction processes. Fischer (1997) proposed the use of 4D technologies (3 dimensional technologies plus a time factor) to model and simulate construction processes. Recent work in the application of VR in construction includes that of Jones and Webb (1997) and Ha (1997). Jones and Webb developed an open VR system that allows for better communication across the various participants of a construction project. Three demonstrators have been developed as part of this work which support activities such as contractor briefing, environmental impact and acoustic modelling. The VRML (Virtual Reality Modelling Language) standard was used to implement these demonstrators. This has resulted in a relatively cheap web-based open system which can allow many participants in the construction sector to benefit from such work. However, it has to be said that this development is still at the prototyping stage. Ha (1997) has developed a VR-based design co-ordinator that can be used by designers at
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the early stage. The system has been implemented by integrating VR, databases and video conferencing technologies. The main limitation of this system is the lack in its web-based capabilities. Other work includes that of Stone (1995) and Griffin (1995) on how VR can be used as design tools. Retik (1995) and Lorch(1995) highlight the importance of VR in animation and simulation tools. Alshawi & Faraj (1995) suggest that VR should be used as the interface for 3D models and databases. Most of the aforementioned work has impacted on the types of technologies proposed in this paper which can be used for housing specific projects. The Computer-Integrated Construction Group, at the National Institute of Standards and Technology (NIST) US, have been using VRML as an open-standard visualisation tool in modelling construction process. The group has taken the dynamic nature of the more recent VRML2.0 standard and used it to model the dynamics of a construction site, including time frames and even the manipulation of machinery on site. The work of Robert Illustrations from NIST.
Lipman has been used in the development of the VRML interface described in this paper.
With regards to housing specific research, work is underway at Loughborough University in the UK to evaluate the benefits of using VR within the housing market (Whyte 1998). The most relevant work in this area is related to the FutureHome Project. This project aims to develop state of the art affordable housing across the European Union. The project is developing new production methods and will rely heavily on the use of IT to model the future home in Europe. The developed model will
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support the design of future homes, constraint modelling as well as time and cost modelling (http://simply.cv.ic.ac.uk:8080/FH/index.htm, Feb 2000).
The proposed system
Figure 1 illustrates the system architecture for the proposed model that supports better integration of information within the housing market. The targeted software applications include AutoCAD, a project management tool, an estimating tool, and a virtual reality package. Each package stores and retrieves information from the database independent of the other packages. For each package, an interface has been built that translates data from the package’s internal representation to the data model. The synchronization of these packages is controlled by a separate module, called the Process Controller. This is in-line with the process-driven integration approach adopted for the system. This Process Controller performs the role similar to a project manager. It allocates database access permission to the included software packages, their operation sequences, information flow, etc.
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VRML browser
AutoCAD
Project Planning
Cost Estimating
Object Recognition
Data mapping
Data mapping
VRML Code Generator
Process Controller
Integrated project database
WEB-based
Process model
Data model
Figure 1 The architecture of the system
The Design Interface A data model describing the design of buildings was developed in AutoCAD. This model contains concepts such as building element, space, etc. This model has been implemented as an object oriented database (objectstore). Each concept when implemented can be referred to as a class. Space is therefore implemented as a class. The classes supported by the object-oriented database have their counterparts in the AutoCAD drawing package. For instance, the user will be creating an instance of the concept "wall" or "space" within AutoCAD, but the information underlying these concepts are defined within the database.
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An interface between AutoCAD and the Objectstore proprietary database was implemented. The AutoCAD user interacts with its drawing editor using familiar commands. Graphical representations of building elements can be produced within the AutoCAD package. However, the information regarding these elements will be stored in the object-oriented database rather than in the AutoCAD drawing database. This approach allows information about the geometry, shape, cost, material, of a building element object to be stored within the same database.
AutoCAD was chosen because of its popularity in the construction industry. However this package is used as a front end to display images and graphical representations, but the information related to these objects is stored in the object oriented database rather than the AutoCAD drawing files to enable the proper modelling of design information.
The estimating interface
Once a building is created through AutoCAD, the estimating application can be used to examine the costs of the building project. A resource-based estimating application was developed. It includes a library of standard work items and standard resources, which can be company specific, to identify work items and resources for a project. The user can start a new project and copy this library into the new project and use the most appropriate work items. Changes can be made to the quantity, rate, etc. and see the cost implications. Alternatively, the user can generate the work items and quantity take-offs from the design model. The work items will then pull the appropriate resources associated with them. The user can experiment with the design model and see the cost changes within the estimating package. The cost data was taken from recently
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completed work and the individual work items from analysis of the construction process and pre-defined cost/item libraries used by the UK industry. The application used to represent the cost-estimating package was Microsoft Excel. The choice of application is significant and a decision is based on connectivity (technical) and rate of use (economic).
Figure 2 the estimating interface
The project planning interface
The project planning interface is based on the Microsoft Project application. The choice of this application is based on the popularity of the software among the potential client base, as well as the ease with which it can be readily integrated with the database. Principally, the project planning interface adds a timeline to the cost/item equation, and is used to sequence and time individual work items identified in the 8
analysis of the construction process. In some instances, aggregated sequences are already pre-defined by the industry, and these are identified and incorporated into the design of the database. The user is free to make adjustments to the time scale for each work item or sequence, and see how this impacts on the overall cost.
Figure 3 The planning interface
The virtual reality interface
The potential of using Virtual Reality (VR) as an interface for an integrated project database using the World Wide Web is of crucial importance. VRML (Virtual Reality Modelling Language) is one of the newest open technologies on the web. It allows the creation of 3D views that can be explored in real time. With the rapid development of computing and communications technology, it is now possible to access information residing on a computer remotely. This capability can be exploited in an integrated construction environment to maximise the information sharing between different
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professionals. For instance, site engineers can query the database from their sites if they have access to a modem and the Internet.
Virtual Reality has usually been regarded as a visualisation tool. However, the system described in this paper has used VR as a user interface. For instance, the user should interact with a 3D column in VR rather than a column in traditional database environment. This will allow the construction practitioners better access to information and motivate them to use integrated databases.
The Virtual Reality (VR) application reads information about the design produced in AutoCAD from the database and displays it in a virtual reality environment. This provides better visualisation using the web-based VRML. This utility is used as a means of interrogating the integrated database remotely over the Internet. The user can interact with individual components of a structure represented in VRML by simply clicking with the mouse. Information relating to the component is then retrieved from the database and displayed in an information window inside the browser. (Figure 4.)
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Figure 4. A VRML view of a housing project
The process management interface
Projects in the construction industry are characterised by large numbers of actors working concurrently at different locations and using heterogeneous technologies. The system is designed to support such kind of collaboration by developing an integrated construction database that can be accessed by any of the actors. To ensure consistency and integrity of the shared project database, there need to be some constraints on how each actor can and cannot interact with the database.
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The Project Manager utility developed aims to provide process management functions usually performed by a project manager. These functions include give permission to communications between the different actors at a given time and to monitor the progress of each task of the project. An example of use of this utility is to limit access and manipulation of a given project design to only participants which are involved in this process. It can also be used to freeze or unfreeze a design on the request of the client who might be happy with a version of design and therefore needs not to be altered. This can be also applied to project costing, planning and virtual reality interface.
An illustrative output
Figure 5 illustrates an output from a similar system developed at Salford. The developed prototype builds on a previous project called (OSCON: Open Systems for Construction, see figure 5). The AutoCAD design interface was used to generate the design layout of the building. In reality, the design information was instantiated in the integrated object oriented database and displayed in AutoCAD. The design information was then used in generating quantities which are used by the time and cost planning prototype software. Durations and rates of various construction activities were produced by the system. The VRML application was used to show the building in 3D and to retrieve information about specific objects in terms of cost and time.
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Figure 5 an illustration of an output from a similar system
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The Potential Uses of the system
The potential benefit of using the system is in the automation of quantities take off, cost estimating, time planning and the remote access of such information. The various parties will be able to quickly produce a prototype that can be evaluated in terms of design, cost and time implications and the identification of buildability problems. The application of the system in the housing industry will undoubtedly change the way projects are conducted within this industry. Through a pilot study implementation, the project seeks to demonstrate how integrated project database can bring immediate business benefit in housing projects. The open architecture of the system will ensure that this will be achievable. The functionality, however, will be enhanced by developing a large number of objects that allow the system to be used on real life projects and tested.
Collaboration support
The developed system intends to support the collaboration of a multi-disciplinary project team located in different parts of the country; some may be on-site, others located at an administrative office. What each has in common is access to a computer and the Internet. Computer based communication and collaboration tools will then be used to connect project participants and support the information flow and processes of the design and construction activities.
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Collaborative working using computers is the theme of two research areas; computer mediated communication (CMC) and Computer Supported Co-operative Work (CSCW). In practice the two areas often overlap in producing actual technical solutions. CMC is concerned with both synchronous and asynchronous communication using computer networks as a medium. The communication media include audio, visual or a mixed format. CSCW applies CMC technology to solutions for collaborative working practices by providing a centralised work store, version control, concurrent work processes, etc.
The advent of the Internet has greatly enhanced the operational scope of both CMC and CSCW. There is now a wide range of ready-made tools aimed at supporting projects where participants are potentially widespread. The developed system will explore the full potentials of these tools and design a communication infrastructure to ensure that the integrated project database prototype is used effectively by the participants.
To facilitate flexible communication, as well as file sharing, between participants in the design process, a computer supported collaborative work tool known as BSCW, was chosen. BSCW has been developed by a German Institute for Applied Information Technology and its principal advantage is that it is completely web based, without the need for a separate client application or plug-in. BSCW provides a secure environment to provide access to user specified interest groups, exchange messages and arrange meetings.
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Performance Indicators
The following framework has been developed to assess the performance of the developed system. It describes the types of processes and stakeholders involved
Process - Process Title Description of process prior to Description of process after the the implementation of System implementation of the system Database, indicating how the process has changed. Identify those involved in Identify those affected by change to the system system
Description of Process
Stakeholder/s
Benefit Type Efficiency (£)
Indicator These are quantitative indicators that will generally be measured in cost or time.
Effectiveness (Q)
These are qualitative benefits that the system may bring. They may not have a direct monetary value, but improve the quality of the way a process is carried out These are benefits that reflect wider improvements in the process that may reflect long term strategic goals.
Business Performance (S)
Benefits These will be the value of the change in the quantitative indicators between the pre and post implementation stages The qualitative benefits will be described. This could include customer satisfaction or an improvement in quality. These are broader qualitative issues that will be recognised at the strategic level such as development of IT strategy or improved long term competitiveness.
Table 1 Perfomance measurement framework The performance model has been tested within a housing firm to evaluate the benefits that can be obtained from using the model. Savings in terms of time and cost and improvements to quality have been identified by the company evaluating the system. Also, better innovation and learning have been considered as long term goals that the company will be able to realised from using the developed system.
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Conclusions
This paper presented a web-based virtual model that supports the better integration and visualisation of housing projects information. The model is centred around a project integrated database that supports the function of design and cost and time planning information. The system offers potential benefits to the housing market through the proper integration of the various participants involved in a housing project. The whole supply chain within the housing market including clients, developers, consultants, constructors and potential property purchasers will benefit from the development of an integrated model. This paper has demonstrated the types of benefits that can be obtained from using the developed system.
References
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