{'fraction_non_alphanumeric': 0.017235188509874325, 'fraction_numerical': 0.0017953321364452424, 'mean_word_length': 5.360730593607306, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Practical and Research Issues in using Industry Foundation Classes for Construction Cost Estimating

Industry Foundation Classes (IFC) have made substantial progress in recent years, and many design software companies now provide export capabilities of IFC-based product models. Consequently, product models are starting to become available from commercial design software programs used in the building construction industry. Yet, there has been limited testing of IFC-based product model representations to support the many processes and tasks required from construction professionals. In particular, IFC-based product models contain quantity information that could be used for cost estimating. In this research study, we assess the usefulness of IFC's to meet the practical needs of construction cost estimators. On average, each item in a cost estimate is created seven times throughout the life of a project (Laitinen 1998). Consequently, it is critical that IFC's do not only support the generation of cost estimates, but also assist estimators with the maintenance of cost estimates throughout the project life cycle. This report shows that an IFC-based product model contains most of the information needed to create a cost estimate. The IFC's provide the information about the types of components and their dimensions and quantities needed for cost estimating. In essence, they help estimators take off quantities automatically and establish an electronic link between a component in a 3D-product model and a cost item in a cost estimating database to create a cost estimate. However, existing estimating software lacks the functionality necessary to assist users in maintaining cost estimates throughout the project, especially in the case of design changes. The reason is that in addition to material quantities, product features, such as repetition and dimensional modularity, also affect construction costs. This report shows that product features determine largely whether a particular cost item from a cost estimating database is the appropriate cost item with the correct unit cost and product rate assumptions. Hence, estimating software must be able to identify product features from an IFC-based product model to assist estimators with creating and maintaining cost estimates. Without computer support to store and use these meta-data about the relationships between cost information and product model components the estimators will need to remember when to adjust the cost information in the case of design changes so that the cost estimate and project scope descriptions are in balance. However, on many projects designs change often and there are thousands of links or relationships between cost items and product model components. Therefore, it is unlikely that …