Historical building BIM parametric modeling method

Abstract

The invention relates to the field of BIM modeling, in particular to a historical building BIM parametric modeling method. The method comprises the following steps that a historical building component classification database is constructed, the historical building component classification database divides historical building components into seven categories, each category is associated with a parameterization template, the parameterization template comprises geometric parameters and culture attribute fields, and the culture attribute fields are associated with a culture database. Historical building basic data are obtained, contour lines and feature points in the historical building basic data are extracted, and then the parameterized template is matched, so that a parameterized instance is obtained; and assembling the parameterized instances into a historical building BIM model, loading the BIM model and the multi-modal culture data in the culture database in a visual platform, and generating an interactive three-dimensional scene. The modeling of the historical building in a parameterized manner is realized, the engineering difficulty is reduced, and the finally generated three-dimensional scene is more real and immersive.

Description

Technical Field

[0001] This application relates to the field of BIM modeling, and particularly to a parametric modeling method for historical building BIM. Background Art

[0002] With the wide application of digital technology in the activation and utilization of cultural relics, the protection of cultural heritage, and the protection and inheritance of urban and rural historical cultures, BIM technology has gradually become the core tool for the protection and restoration of historical buildings. However, due to the complexity of their structures and the uniqueness of their cultural attributes, historical buildings are essentially different from traditional modern buildings. The existing BIM modeling technologies in the prior art are often designed for modern buildings and cannot effectively express the historical building information model completely, with poor precision in expressing historical building components, large engineering quantities for separately modeling historical building components, and a lack of expression of the cultural background contained in these components. Summary of the Invention

[0003] This application provides a parametric modeling method for historical building BIM, including the following steps: Construct a classification database for historical building components. The classification database for historical building components classifies historical building components into foundation classes, column classes, enclosure classes, beam and purlin classes, decoration classes, roof classes, and bracket sets classes. Each class is associated with a parametric template, and the parametric template includes geometric parameters and cultural attribute fields, and the cultural attribute fields are associated with a cultural database; Obtain the basic data of the historical building, and extract the contour lines and feature points from the basic data of the historical building; Match the contour lines and feature points with the parametric template to obtain parametric instances; Assemble the parametric instances into a historical building BIM model, and load the BIM model and the multimodal cultural data in the cultural database in a visualization platform to generate an interactive three-dimensional scene.

[0004] Specifically, the bracket sets components in the classification database for historical building components are divided into three subclasses: three-step, five-step, and seven-step according to the number of cantilever layers, and two subclasses: inner eaves and outer eaves according to the position; The geometric parameters in the parametric template associated with each subclass include: The proportional constraint between the length of the horizontal hua arch and the height of the longitudinal qiao ang; The range of the biting angles between components of each layer; The recursive formula for the modularized dimensions of the doukou.

[0005] Specifically, the geometric parameters in the parametric template associated with the foundation class components in the classification database for historical building components include: The reduction ratio of the taiming, douban, and maitou; Parity constraint on the number of steps of the tamped platform; Adaptive layout algorithm for the carved patterns on the waist part of the Xumizuo (Buddha's pedestal).

[0006] Specifically, the cultural attribute fields include: Era label, used to associate the mapping table between the Chinese dynasty chronology and the Gregorian calendar years in the cultural database; Pattern code, used to bind the vector data of the carved pattern atlas in the cultural database; Restoration record, used to hyperlink to the construction unit, material consumption, and image data of previous repairs in the cultural database.

[0007] Specifically, the method for obtaining the basic data of the historical building includes: Collect the geographical location information of the historical building; Take multi-angle images of the historical building, images of surrounding auxiliary facilities, and images of surrounding vegetation; Measure the component size data of the historical building.

[0008] Specifically, the method for extracting the contour lines and feature points from the basic data of the historical building includes: Extract the coordinates of key mortise and tenon joints of the Dougong (bracket set) components and construct a topological connection relationship diagram; Extract the extreme points of the edge curvature of the corner column stones and step stones of the platform base components; Extract the pattern skeleton lines of the carved components and calculate their fractal dimensions as feature values.

[0009] Specifically, the method for matching the contour lines and feature points with the parametric template includes: Perform Fourier descriptor transformation on the Dougong contour lines and match the hierarchical features in the frequency domain; Calculate the Hausdorff distance of the carved pattern skeleton lines and screen the templates with similarity higher than the threshold; When there is no matching template, trigger the manual review interface and record the new template in the classification database.

[0010] Specifically, when assembling the parametric instance into the BIM model of the historical building, the following inspections are carried out: Mechanical balance check of the Dougong out-jumping direction and the beam frame lifting and folding angle; Visual coordination check of the platform base taper ratio and the column base diameter; Adaptive interpolation algorithm check of the carved pattern layout density and the component surface curvature.

[0011] Furthermore, it further includes the steps: Generate a parametric tree model based on SpeedTree and define the branch hierarchy relationship, canopy structure, and seasonal change parameters; Import the tree model into the Revit scene through a coordinate conversion plug-in to match the spatial positioning and scale of the BIM model. Use light baking technology to adjust the tree material texture map to make it consistent with the lighting conditions of the BIM scene.

[0012] Furthermore, it also includes the steps of: Convert the Revit model into a UE4-compatible format through a plug-in, retaining the geometric accuracy of components and the property table. Bind component properties and dynamic effect scripts in UE4 to achieve real-time driving of weather switching and character interaction. Configure scene event triggers to respond to external inputs, where the external inputs include user clicks and sensor signals.

[0013] The present application has the following technical effects: It provides a modeling method with better expression effect for the component characteristics of historical buildings, can parametrically model historical buildings, reduces the engineering difficulty, and at the same time can make the finally generated 3D scene more realistic and immersive. Description of the Drawings

[0014] By referring to the accompanying drawings and reading the detailed description below, the above and other purposes, features, and advantages of the exemplary embodiments of the present application will become easily understandable. In the drawings, several embodiments of the present application are shown in an exemplary rather than restrictive manner, and the same or corresponding reference numerals represent the same or corresponding parts.

[0015] Figure 1 It is a flowchart of the historical building BIM parametric modeling method in the embodiments of the present application. Detailed Embodiments

[0016] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application.

[0017] In the implementation process of the historical building BIM parametric modeling method of the present invention, it is carried out according to the steps as Figure 1 shown: First, construct a classification database for historical building components. In this embodiment, when constructing the classification database for historical building components, the components are divided into seven major categories: podium classes, column classes, enclosure classes, beam and purlin classes, decoration classes, roof classes, and bracket sets classes. Each category is further subdivided into subclasses. For example, bracket set components are divided into three types: three-step, five-step, and seven-step according to the number of cantilever layers, and are divided into two subclasses: inner eaves and outer eaves according to the installation position. The parametric templates associated with each subclass contain geometric parameters and cultural attribute fields. The design of geometric parameters must strictly follow the traditional construction methods. For example, the ratio constraint between the length of the horizontal cross-arch and the height of the longitudinal warping and soaring in the bracket set template is based on the modular principle of "Rules of Qing Dynasty Architecture". The range of the biting angles between components at each layer is verified for its mechanical stability through finite element analysis, and the recursive formula for the modular size of the doukou is based on the historical construction rule of "taking the doukou as the basic module". Through database association technology, the cultural attribute fields dynamically bind the age label and the Gregorian year mapping table, precisely match the pattern code with the vectorized carved pattern atlas, and the repair records integrate the construction logs, material usage, and image data of previous repairs through hyperlinks to form a complete cultural information chain.

[0018] Then, obtain the basic data of historical buildings. In this embodiment, the geographical location information is obtained through lidar scanning and drone oblique photography technology to generate point cloud data with centimeter-level accuracy. The measurement of component dimensions uses a complementary method of total station and three-dimensional laser scanner. For complex carved components, a handheld structured light scanner is supplemented to capture the microscopic curvature. The multi-angle image acquisition follows a standardized process. A full-frame camera with a resolution of not less than 50 million pixels is used to photograph the building facade and detailed structures at an incident angle of more than 70 degrees. At the same time, the roof shape and the panoramic view of the surrounding environment are obtained through drone aerial photography. For vegetation data, in addition to taking high-resolution photos, the diameter at breast height, crown width, and branch fractal characteristics of ancient and famous trees also need to be recorded to provide a basis for subsequent parametric modeling.

[0019] After obtaining the basic data, extract the contour lines and feature points from the basic data of historical buildings. The key mortise and tenon joint coordinates of the bracket set components are extracted through point cloud registration and topological analysis, and a connection relationship graph between the nodes is constructed to restore the mechanical transmission path of traditional wooden structures; the extreme curvature points of the corner column stones and step stones of the podium components are identified using the curvature flow algorithm to ensure the accurate calculation of the tapering ratio; the extraction of the skeleton lines of the carved patterns combines edge detection and morphological thinning algorithms, and the complexity of the patterns is quantified through fractal dimension calculation to provide feature values for template matching. The intermediate data generated during the feature extraction process is stored in a distributed database to support multi-threaded parallel processing to improve efficiency.

[0020] After extracting the contour lines and feature points from the basic data of historical buildings, the contour lines and feature points are matched with the parametric templates. In this embodiment, the contour line of the bracket sets is mapped to the frequency domain space through Fourier descriptor transformation, and the low-frequency components in the matching hierarchical features are used to identify the basic form, while the high-frequency components are used to verify the detailed decoration; the skeleton line of the carved pattern adopts an improved Hausdorff distance algorithm, and a weight coefficient is introduced to optimize the matching accuracy. When the similarity is lower than the preset threshold, the system automatically triggers the manual review interface, and experts intervene to optimize the template or create a new template for storage in the library. During this process, the machine learning model continuously learns the results of manual review and gradually improves the accuracy of automatic matching.

[0021] After obtaining the parametric instances, the parametric instances are assembled into a BIM model of the historical building. The BIM model and the multi-modal cultural data in the cultural database are loaded in the visualization platform to generate an interactive three-dimensional scene. In this embodiment, the mechanical balance check of the bracket set's out-jumping direction and the beam frame's lifting and folding angle is based on finite element analysis to simulate the load distribution, preventing structures that violate the traditional construction logic from appearing in the virtual model; the visual coordination check of the pedestal's tapering ratio and the column base diameter uses a visual perception model to quantitatively analyze the impact of the proportional relationship on the overall style of the building; the arrangement density of the carved pattern is dynamically adjusted by the curvature adaptive interpolation algorithm to ensure the natural extension of the pattern on the surface of the arc-shaped component. After the model assembly is completed, the number of triangular patches is optimized by a lightweight engine, and the model face count is controlled within the rendering load range of the visualization platform while retaining the detailed features.

[0022] In this embodiment, the construction of the vegetation system adopts a dual strategy of parameterization and real-scene integration. The SpeedTree software is used for three-dimensional tree modeling. The tree stump is added through the view and the white point is adjusted to draw the shape of the tree trunk. Subsequently, the branches of the Big Branches type are added and the hierarchical relationship is adjusted. Finally, the material texture map is imported and the wind effect is set. The generated tree model is imported into the Revit scene through a customized coordinate transformation plug-in. The plug-in is built with a scale and space alignment algorithm to ensure the precise matching of the vegetation model and the BIM building model. In the light baking stage, a physically based rendering technology is adopted, combined with the solar illumination angle and material reflectivity of the historical building scene, to dynamically adjust the light transmission rate of the leaves and the light and dark transition of the tree trunks, so that the lighting effects of the vegetation and the building are seamlessly integrated.

[0023] The interactive functions of the visualization platform are realized relying on the real-time rendering capabilities of the Unreal Engine (UE4). In this embodiment, the Revit model is converted into a UE4-compatible format through a plug-in, retaining the geometric accuracy of components and the property table. In the UE4 editor, component properties are bound to dynamic scripts. For example, clicking on a bracket set component can trigger a pop-up window for cultural properties, displaying the associated pattern atlas and repair records; the dynamic weather system simulates the infiltration effect of rain and snow on the building surface by calling material instances and particle systems; the day-night switching function is based on the precise calculation of the positions of the sun and the moon, supporting users to customize the time or synchronize with the system time in real-time. In addition, the scene event trigger can receive external sensor signals. For example, when the temperature and humidity sensor detects environmental changes, it automatically adjusts the fading degree of the model material to simulate the weathering effect.

[0024] Obviously, the above-described embodiments are some, but not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without creative efforts fall within the scope of protection of this application.

[0025] It should be understood that when the claims, specifications, and drawings of this application use terms such as "first" and "second", they are only used to distinguish different objects and are not used to describe a specific order. The terms "including" and "comprising" used in the specifications and claims of this application indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

Claims

1. A BIM parametric modeling method for historical buildings, characterized in that The following steps are involved: Constructing a historical building component classification database, wherein the historical building component classification database classifies historical building components into base, column, enclosure, beam, decoration, roof and bracket, each category is associated with a parametric template, the parametric template includes geometric parameters and cultural attribute fields, and the cultural attribute fields are associated with a cultural database; Acquire basic data of historical buildings, and extract contour lines and feature points from the basic data of historical buildings; Matching the contour line and the feature point to the parameterized template to obtain a parameterized instance; The parameterized instances are assembled into a BIM model of a historical building, and the BIM model and the multimodal cultural data in the cultural database are loaded into a visualization platform to generate an interactive three-dimensional scene.

2. The historical building BIM parametric modeling method according to claim 1, wherein The bracket components in the historical building component classification database are divided into three subcategories according to the number of layers, namely, three-step, five-step, and seven-step, and are divided into two subcategories according to the position, namely, inner eaves and outer eaves; The geometric parameters in the parametric template associated with each subclass include: The ratio constraint between the horizontal arch length and the vertical rise height; The range of the occlusal angles between the components of each layer; Recursive formula for the modular size of bucket mouth.

3. The historical building BIM parametric modeling method according to claim 1, characterized in that The geometric parameters in the parametric template associated with the base components in the historical building component classification database include: The proportion of the points of the platform, steep board and buried head; Odd-even constraint on the number of stomping steps; Adaptive arrangement algorithm of the carved patterns on the waist of the Sumeru pedestal.

4. The historical building BIM parametric modeling method according to claim 1, characterized in that The cultural attribute fields include: A decade label, used to associate the Chinese dynasty chronology and Gregorian calendar year mapping table in the cultural database; Pattern code, used to bind the vector data of the carved pattern atlas in the cultural database; Restoration records are used to hyperlink to the construction units, material usage and image data of previous repairs in the cultural database.

5. The historical building BIM parametric modeling method according to claim 1, wherein The method for obtaining basic data of historical buildings comprises: Collecting geographical location information of the historical buildings; Taking multi-angle images of the historic building, images of surrounding ancillary facilities and images of surrounding vegetation; Measure the dimension data of the components of the historic building.

6. The historical building BIM parametric modeling method according to claim 1, characterized in that The method for extracting contour lines and feature points from the historical building basic data comprises: Extract the key mortise and tenon joint coordinates of bracket components and construct a topological connection diagram; Extract the edge curvature extreme points of corner column stones and step stones for the base components; The pattern skeleton lines are extracted from the carved components, and their fractal dimensions are calculated as the eigenvalues.

7. The historical building BIM parametric modeling method according to claim 1, characterized in that The method of matching the contour line and the feature point to the parameterized template comprises: Perform Fourier descriptor transformation on the bracket contour to match the hierarchical features in the frequency domain; The Hausdorff distance calculation is performed on the skeleton line of the carved pattern to select the templates with similarity higher than the threshold; When there is no matching template, the manual review interface is triggered and the new template is recorded in the classification database.

8. The historical building BIM parametric modeling method according to claim 1, characterized in that, When assembling the parameterized instances into a historical building BIM model, the following checks are performed: Mechanical balance check of bracket jumping direction and beam lifting angle; Visual coordination check of the taper ratio of the platform and the diameter of the column base; Verification of adaptive interpolation algorithm between carved pattern arrangement density and component surface curvature.

9. The historical building BIM parametric modeling method according to claim 1, characterized in that Also includes the steps: Generate a parametric tree model based on SpeedTree, and define the hierarchical relationship of branches, canopy structure and seasonal change parameters; Import the tree model into the Revit scene through a coordinate conversion plug-in to match the spatial positioning and scale of the BIM model; Adjust the tree material map using light and shadow baking technology to make it consistent with the lighting conditions of the BIM scene.

10. The historical building BIM parametric modeling method according to claim 1, characterized in that It also includes the steps: Convert the Revit model into a UE4-compatible format through a plug-in, retaining the geometric accuracy of components and the property table; Bind component properties and dynamic effect scripts in UE4 to achieve real-time driving of weather switching and human interaction; Configure scene event triggers to respond to external inputs, where the external inputs include user clicks and sensor signals.

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