Research On The Technology Of Bim-based Intelligent Aided Design Platform

Digital architectural design plans have abounded and been widely used in the construction field. It is significant to use the intellectual wealth and accumulated experience existing in those plans. By taking advantage of the computer technology, the intelligent computer-aided design platform can be constructed and used in the construction or educational practice. It can provide technical support for the architects' knowledge reuse process in many ways: the architectural knowledge's acquisition, the learning of design experience and specifications, the inspiring of the design inspiration, the reuse of some parts of the design plans. As a consequence, the architectural design process is more efficient, convenient and enjoyable. The platform can also be an effective way to improve the efficiency and quality of the computer-aided architectural design.By expressing the architecture's geometric, physical and functional information and using the digital technology, BIM becomes a kind of information resource sharing technology that supports the buildings' lifecycle management. BIM model is the core of the BIM technology. With the rapid development and wide application, the BIM model's number will be larger. The rational use of these resources can effectively shorten the design cycles, reduce design costs and improve design quality. Case-Based Reasoning(CBR) is an intelligent design theory. Its basic principle is to solve the current problem by reasoning on the previous problem solving experience(ie case). When taking advantage of this theory to construct the BIM-based intelligent aided design platform, the key issue includes two aspects: the models' selection and expression, the classification and retrieve method's construction. The aforementioned important feature of the BIM model is that it contains much implicit architectural spatial relationships. However, the widely used method that considering keywords as search criteria can only be used in the describable case and the architectural spatial relationship(ASR) is difficult to describe with words. So the study of computer architecture spatial relationships of expression is a prerequisite for efficient retrieval of BIM model. Graph theory is a theory describing the relationship between the things in the real world based on the mathematics and computer theory. Architecture discipline created the space syntax theory based on the graph theory to express the ASR and analyze these relationships. Taking advantage of the space syntax theory and graph theory, it's possible to establish attribute relationship graph providing computer expression of the ASR. When using the attribute relationship graph for BIM model's classification and retrieval, the difficulty is to construct the inexact graph matching method with high speed and accuracy. It is also the research hotspot and nodus when it comes to the graph data's classification and retrieval in the computer science.In this paper, the research goal is the knowledge reuse of architecture design; the guide is the CBR theory. Aiming to the BIM models' implicit information that revealing the architectural spatial relationship, this paper converted the ASR based BIM models' classification and retrieval into graph matching. This progress used the graph theory and Space Syntax theory, studied the graph model expressing the architectural spatial relationship and its formal description & automatic extraction algorithm. The article studied the inexact graph matching method based on the graph kernel and graph embedding. Moreover, it studied the BIM models' retrieval method based on the function bubble sketch and the prototype's construction, thus it can provide more efficient services for the computer aided architecture design. The Dissertation work includes the following aspects:1. The architectural spatial relationship can be presented and formally described by constructing mathematical models, thus the quantified information can be used by the computer for ASR based intelligent information processing. This paper constructed the Space Syntax's Attribute Relationship Graph(SSARG) based on the graph theory and Space Syntax theory, then proposed a formal description of the architectural spatial relationship's related attributes——the Architectural Space Attribute's Relationship Graph model(ASARG) and its extraction algorithm. Moreover, this article used the Revit API and C# language in the Revit platform and developed the relevant plug for the ASARG's extraction and property calculation through the secondary development. Finally, the paper proposed the BIM graph matching test library's design strategies and the corresponding BIM graph matching test library(BIMGM) based on XML, thus laid a solid data foundation for future research.2. In the field of structural graph-based pattern recognition, the existing graph matching methods have high complexity and lack related variables to describe the graph's topological attributes. So it is difficult to satisfy the ASR-based BIM models' matching or the generic graph matching speed's requirements. A graph-kernel-based inexact graph matching method was proposed in this paper on the basis of SSARG and ASARG. By constructing the new graph kernels based on space syntax and shortest path, this paper could map the graph data space to the feature vector space implicitly, thus the similarity measurement between graphs was converted into the dot product in the feature vector space. Moreover, the SVM could be used to classify the graph data. Compared with other graph matching method, this method has lower complexity with higher classification recognition rate. Given that some of the graph data or the BIM models only have topological attributes, this method is a basic graph matching method providing better performance.3. In the domain of traditional graph-based pattern recognition, it is difficult to take advantage of the rich mathematical methods of the statistical pattern recognition. So it is difficult to satisfy the ASR-based BIM models' matching or the generic graph matching speed's requirements. Given the basic idea of the graph embedding, this paper proposed a series of graph embedding methods based on the SSARG and the ASARG, including the graph embedding method based on the topological features and domain features, the graph embedding method based on multi-scale features, the improved K-means clustering graph embedding method. With all these methods, the structural pattern recognition could be converted into statistical pattern recognition, thus the rich mathematical methods in the statistical pattern recognition field could be used to implement the inexact graph matching. Compared with other graph matching method, the above methods adopt the statistical methods and take fully advantage of the graph's topological feature constructed based on the space syntax, thus the algorithms have lower complexity with higher classification recognition rate. These algorithms can be basic graph matching algorithms providing better performance for the graph data or the BIM models which have topological attributes and domain attributes.4. The aforementioned important feature of the BIM model is that it contains much implicit architectural spatial relationships. However, the existing BIM model retrieval methods fail to take advantage of this feature effectively and lack the appropriate retrieval interface. This paper proposed a BIM model retrieval method based on the function bubble sketch and constructed the prototype system. The retrieval conditions' input was divided into two parts: the hand-drawn structural analysis sketch input and vector structural analysis sketch input. Moreover, the method extracted the information of the sketch, including the architectural space's topological information and domain attribute, and constructed the ASARG model. Combining with the graph-embedding-based feature extract method, the ASARG was converted into feature vector space. Finally, this paper implemented the BIM model's retrieve method based on the architectural spatial relationship by constructing the similarity measure function in the feature vector space. On the basis of the above steps, this article accomplished the construction of the prototype system, verified the effectiveness of this method through experiments and provided key technologies for the construction of the BIM model retrieval platform based on the function bubble sketch.Our study provides basic theory and key technologies for intelligent computer-aided architectural design and the vast amounts of information's processing.