Object-oriented CAD tool implementations for the construction industry

Karl-Johan Seren, Matti Hannus, Kari Karstila, Markku Kihlman, Jukka Pellosniemi

    Research output: Book/ReportReport


    Construction projects incorporate a large variety of products and different viewpoints of numerous participants. Because of this the construction industry needs software tools independent of specific applications which can easily be used for and tailored to different tasks. The construction industry is too fragmented to support any significant software development unless a common software basis can be used for different applications. Unlike many other products designed using CAD systems, buildings are mainly assembled from prefabricated components and materials. These basic parts are to a large extent described by non-geometrical information. The objective of the project described in this report - the OOCAD project - was to further refine and develop previous work in the Finnish construction industry concerning computerized methods for describing and designing buildings as product models. The work included the development of a formal generic product model on a conceptual level (the OOCAD model) based on object-oriented concepts and the definition of a neutral data exchange file format (the OXF-format) mapping the model as closely as possible. The model is based on a hierarchical composition of objects with part-of relationships where the data of real world entities, such as buildings, consist of two kinds of objects: types and instances. This dualism was introduced to avoid redundant data: the type objects describe the common data of one or several identical objects, such as shape and material, whereas the instance objects describe occurrence-specific data, such as position. To illustrate the use of the model, generic application frameworks using three different software tools were developed, all of which use the neutral OXF file format for data exchange. A commercial CAD-package (AutoCAD) was enhanced with basic functions for creating and editing product model-based designs. A relational database management tool (dBase IV) was used to develop an application for storing and reorganizing product models and generating reports from product model data. An object-oriented programming tool (Actor) was used to develop an application running in the MS-Windows environment for creating, browsing through and editing product models.
    Original languageEnglish
    Place of PublicationEspoo
    PublisherVTT Technical Research Centre of Finland
    Number of pages95
    ISBN (Print)951-38-4354-8
    Publication statusPublished - 1993
    MoE publication typeNot Eligible

    Publication series

    SeriesVTT Tiedotteita - Meddelanden - Research Notes


    • construction industry
    • buildings
    • computer programs
    • object programs
    • computer aided design
    • tools
    • utilization
    • construction materials
    • building components
    • building automation
    • prefabrication
    • methods
    • product models
    • descriptions
    • describing
    • development
    • databases
    • construction management


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