Research On BIM Model Comparison Method At The Component Level

In recent years,digital information technology has developed rapidly and has become an important driving force to promote the development of all walks of life in the world.BIM technology,as a building information technology,has a far-reaching impact on the whole life cycle of architecture.The application of BIM technology has become the trend of the construction industry.As BIM technology is applied more and more widely,there are more and more different versions of BIM models in each stage of the whole life cycle of architecture.The differences between these models can provide decision support for the construction,operation and maintenance stages of architecture.Traditional BIM model comparison is based on visual inspection,manual counting and selective attribute inspection.The results obtained by these methods are random and often unreliable.Although there are some scholars and relevant institutions have studied automatically compare BIM model method,but they all exist a lot of limitations,mostly depends on the model of component ID BIM model comparison,also can only to a specific format,comparing the model file and compare the result of not directly associated with the specific component,specific attributes.In view of these problems,this paper proposes a method for comparing BIM models at the component level,which aims to solve the differences between different versions of BIM models in the same building.The main research contents of this method are as follows:(1)Component matching method based on geometric information and position information of components.The method calculates the geometric similarity of components by constructing their shape distribution.Through the coarse registration and fine registration technology of point cloud data,the registration of the world coordinate system of different versions of BIM model is carried out,and the positional similarity between components is calculated.Combining geometric similarity and positional similarity to carry out component matching.The one-to-one matching of components is realized,and the result of adding/deleting components can be obtained.The matching process completely ignores the influence of the change of component ID on the whole comparison process,making the matching result more accurate and effective.(2)Attribute comparison method based on natural language processing.This method matches attribute class and attribute name by constructing attribute information tree graph.Word segmentation algorithm and symbol processing method are used to preprocess attribute values.Word2 vec method is used to convert the attribute values into vectors,and cosine similarity algorithm is used to calculate the similarity.The comparison of attribute information and the calculation of component attribute similarity are realized.(3)Visualization method of comparison results based on Web3 D.Through the design of the Web interface,the comparison result is correlated with the concrete component,and the linkage between the comparison result and the component is realized at the Web end.Different colors are used to highlight the contrast results of different states.This method realizes the 3d visualization of the digital comparison results and makes the comparison results more intuitive.In this paper,a component-based BIM model comparison method is implemented,which is insensitive to component ID,correlation component of comparison results,and visualization of comparison results.This method can serve all phases of the building life cycle and provide users with more accurate and comprehensive BIM model comparison results..