A bridge engineering drawing and BIM model decoupling generation method and system based on a data model

Abstract

The application discloses a kind of bridge engineering drawings and BIM model decoupling generation method and system based on data model, and it is related to the field of building engineering informatization.The method first constructs a unified central parameterized data source;Then based on the data source, model generation process and drawing generation process are executed in parallel and independently.Model generation process creates three-dimensional BIM model according to data, while drawing generation process directly generates two-dimensional construction drawings from data according to an independent drawing expression rule base, and the core rule forces the drawing label value to use design parameters, prohibiting measurement from three-dimensional model, thereby completely solving the drawing size distortion problem caused by model section of complex linear bridge.The system also integrates automatic font conversion and drawing optimization technology.The application realizes high-quality, fully-automatic design output, significantly improves design accuracy and efficiency.

Description

Technical Field

[0001] This invention relates to the field of engineering, and more particularly to a method and system for decoupling and generating bridge engineering drawings and BIM models based on data models. Background Technology

[0002] In the field of bridge engineering design and construction, with the increasing number of complex and large-scale projects such as urban expressways and interchanges, the demands for design efficiency, accuracy, and collaborative depth have reached unprecedented levels. Digital design methods centered on BIM technology are considered a key path to solving these challenges. In an ideal BIM-driven forward design workflow, the 3D information model should not only be a visualized result but also the sole data source driving engineering design, analysis, construction, and management. Existing technological systems face several interconnected and deep-seated technical bottlenecks: 1. Insufficient automation and geometric accuracy in 3D modeling of complex bridge components. For critical components with complex spatial surfaces, such as the widened top slab of curved bridge sections and the tortuous bottom slab formed by the combined action of longitudinal slope and inclined web, existing general-purpose modeling software or parametric tools (such as simple extrusion and sweep) cannot directly and accurately construct their true form. Designers are often forced to use approximate modeling or segmented splicing, resulting in difficulty in guaranteeing the geometric accuracy of the model, which casts doubt on the reliability of downstream applications such as model-based quantity calculations and collision checks. At the same time, for large-scale projects tens of kilometers long, modeling becomes a massive amount of repetitive labor with low automation and a lack of intelligent parametric associations between model components, leading to slow response to design changes.

[0003] 2. The "model-driven drawing" paradigm has fundamental contradictions under complex spatial alignments. The current mainstream BIM drawing method generates 2D construction drawings by sectioning a 3D model. However, in road and bridge engineering, this method exposes a fundamental flaw: the 2D view outline obtained by sectioning a 3D curved surface model has dimensions that are geometric projection values, not the design intent values ​​required by drafting standards. For example, in the design of a curved bridge with equal width, using parallel section lines for clarity will result in the section plane not being perpendicular to the road centerline, causing the cross-sectional width projection value obtained from the precise 3D model to deviate from the design value (e.g., ...). Figure 2 (As shown). Directly labeling this projection value on the construction drawings not only violates drafting standards but also requires manual correction, severely damaging design efficiency and the authority of the results. This reveals that this paradigm cannot simultaneously guarantee the geometric accuracy of the model and the correctness of the drawing representation.

[0004] 3. Internal coupling within the model generation process exacerbates system-level inefficiency and inconsistency. A deeper problem lies in the fact that existing modeling processes typically intertwine the creation of main beams (large spatial structures) and prestressed steel strands (slender pipe entities) within a linear, coupled workflow. However, their geometric nature and generation algorithms differ significantly: main beam forming relies on complex spatial operations such as "surface trimming" and "model intersection," while steel strand modeling follows a chain logic of "path projection, offset, and scan." This forced coupling leads to complex workflow logic, low computational efficiency, and the generated "hybrid model" further perpetuates section distortion problems. Existing technologies lack consideration for structural decoupling of the model generation process itself, and fail to achieve efficient and parallel collaboration between the decoupled professional modeling workflows and a completely independent drawing generation workflow. Therefore, systematic innovation at the workflow architecture level is crucial to solving these multi-layered challenges and achieving high-quality automated design.

[0005] In summary, existing technologies have significant shortcomings in two key areas: efficiently and accurately creating 3D models of complex bridges and ensuring consistency and accuracy between models and drawings from the outset. Therefore, this field urgently needs a systematic and innovative approach that not only fundamentally revolutionizes the 3D modeling process for complex bridge components, enabling intelligent and batch generation from design data to high-precision models, but also reconstructs the generation logic of models and drawings to ensure that design deliverables automatically and error-free meet the depth and standard requirements of engineering delivery. Summary of the Invention

[0006] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention aims to provide a decoupled generation method and system for bridge engineering drawings and BIM models based on a data model. This solution resolves the problems existing in current technologies by constructing a unified central parametric data source and driving two generation processes in parallel and independently based on this data source. In 3D model generation, the system employs innovative algorithms such as surface trimming and model intersection to achieve high-precision, fully automated modeling of complex spatial components (such as widened top slabs and twisted bottom slabs) from design data. In 2D drawing generation, the system uses an independent drafting rule library to mandate that drawing annotations directly use design parameter values ​​from the data source rather than measuring model geometry, thus eliminating drawing distortion at its source. This data-driven, decoupled generation paradigm, combined with automated font conversion and drawing optimization technologies, ultimately achieves integrated, accurate, and efficient output from design data to high-quality BIM models and standard construction drawings.

[0007] (II) Technical Solution To achieve the above-mentioned objectives, the present invention adopts the following technical solution: A method for decoupling bridge engineering drawings and BIM models based on data models, characterized by the following steps: S1: Build a central parameterized data source.

[0008] The data source is a structured repository for storing and managing all design intents of a bridge engineering project. Its core function is to serve as the single, authoritative data input for all subsequent generation processes, ensuring that the model and drawings originate from the same design truth. This data source typically consists of two collaborative parts: The structured parameter database is a predefined template Microsoft Excel workbook containing multiple worksheets such as "Drawing Frame Parameters," "Overall Bridge Information," "Box Girder Joint Parameters," and "Reinforcement Parameters." It includes a "General Joint" data row, which automatically uses a general value when a specific joint parameter is missing, greatly simplifying input.

[0009] Standardized geometric baseline set: Road centerlines, bridge edge lines, web centerlines, etc., designed in AutoCAD are imported into BIM design environments such as Rhino using specific colors (such as red, green, and magenta) and layer standards, serving as geometric baselines for complex spatial lines that are difficult to parameterize. The system automatically identifies and associates these baselines through color and layer attributes.

[0010] S2: Based on the central parametric data source, the model generation process and the drawing generation process are executed in parallel and independently.

[0011] To address the internal coupling issue in the model generation process mentioned in the background art, this invention first reconstructs the model generation process, splitting it into two independent sub-processes based on the essential differences in the modeled objects: the main beam model creation process and the prestressed steel strand model generation process. The main beam model creation process focuses on generating accurate large-scale structural shapes through spatial geometric operations such as "surface trimming" and "model intersection"; the prestressed steel strand model generation process focuses on performing chained operations of "path projection, offset, and scan" to batch generate pipe entities that meet mechanical and technological requirements. The two sub-processes have focused algorithms and independent logic.

[0012] Based on this, the system constructs a three-layer parallel architecture: the two model generation sub-processes mentioned above, and a completely decoupled drawing generation process. All three start simultaneously, read and process the corresponding data in the central parameterized data source in parallel, and the processing processes are independent of each other and do not communicate with each other.

[0013] (a) Model generation process: The task of this process is to compile a high-precision three-dimensional digital twin model based on the data source for analysis, quantity calculation and construction simulation.

[0014] 1. Main Girder Model Creation Process: Based on the geometric parameters from the data source, the main body of the box girder is constructed through a series of deterministic geometric operations. It further includes: a) Variable width roof plate generation sub-process: Based on the 3D road centerline and cross slope sweep, an initial large surface is generated, and then the surface is trimmed using the "bridge edge line" (green curve) associated with the data source to obtain an accurate variable width roof plate surface.

[0015] b) Complex shape base plate generation sub-process: For inclined web plates and curved bridges, first generate web plate model and base plate reference surface model, then perform Boolean intersection operation on the two to obtain the spatial outline of the base plate, and finally generate accurate base plate surface through lofting.

[0016] c) Parametric detailed construction and assembly sub-process: The chamfer of the box is generated by the "direct construction method" of calculating the intersection line and splicing the triangular facets; after the auxiliary components such as crossbeams and cross diaphragms are instantiated as parametric templates, they are automatically assembled to the main body according to geometric constraints.

[0017] 2. Prestressed steel strand model generation process: This process executes a preset, modular chain of operations to generate steel strand entities in batches: project the two-dimensional layout lines onto the surface of the box girder; offset vertically to the design height; insert control points at the bending points and divide the curves; perform filleting; merge the curves and assign circular cross-sections to generate a three-dimensional pipe model.

[0018] (2) Drawing generation process: This process is completely decoupled from the model generation process. Its task is to directly "translate" the data source into construction drawings. Its core is to call an embedded two-dimensional drafting engine, which works according to an independent drafting expression rule library.

[0019] The drawing representation rule library contains a series of mandatory rules. Its core rule stipulates that for views such as bridge cross sections that are prone to projection distortion due to line shape, all dimension values ​​on the drawings must directly adopt the design parameter values ​​stored in the data source.

[0020] Implementation process (taking a cross-section as an example): When a cross-section of a certain station needs to be generated, the system triggers the above rules. It does not access the 3D model, but directly locates and reads the design values ​​such as "full width of top slab" and "beam height" of the station row in the data table. Then, it uses these values ​​to directly draw the horizontal and vertical cross-section outline in 2D space and adds annotations, thereby ensuring that the annotation values ​​are 100% the design intent values.

[0021] Intelligent drawing optimization: This process also integrates an automatic obstacle avoidance function, which detects conflicts between bounding boxes between annotations in real time and automatically adjusts the drawing layout according to preset rules (such as adjusting leader length and alternating text placement) to ensure the drawing is clear.

[0022] S3: Post-process the graphic files output by the drawing generation process to generate the final delivered drawing files.

[0023] This step aims to convert intermediate drawings generated in the BIM environment into final deliverables that conform to industry CAD standards without loss, with the key being the resolution of font compatibility issues.

[0024] Engineering font conversion processing: Because the drawing process may use reconstructed SHX linear fonts (drawn by geometric curves) in non-CAD environments (such as Rhino), the system performs the following steps to generate editable standard DWG files: a) Synchronous Markup: When generating curved text, a hidden markup object containing font attributes (content, height, font name) is created synchronously at its location.

[0025] b) Intermediate File Generation and Conversion: During export, the program automatically replaces curved text with Windows universal fonts and generates intermediate DWG files. Users can use a dedicated plugin in AutoCAD to batch replace all universal font text in the file with standard SHX font entities based on the marking information with a single click, thus automating the generation of the final DWG file.

[0026] A system for decoupling bridge engineering drawings and BIM models based on a data model, used to implement the above method, characterized in that it includes: Data Management Module: Used to build and maintain the central parameterized data source.

[0027] Model generation module: used to execute the model generation process, which includes a main beam creation submodule (to generate a widened top plate, a complex bottom plate, and detailed assembly) and a prestressed steel strand generation submodule (to model chain steel strands).

[0028] Drawing generation module: It integrates the drawing expression rule library and is used to execute the drawing generation process, including sub-functions such as intelligent obstacle avoidance.

[0029] Output processing module: used to perform the post-processing steps, especially font conversion processing.

[0030] A computer-readable storage medium having a computer program stored thereon that, when executed by a processor, can implement any of the methods described above.

[0031] (III) Beneficial Effects The purpose of this invention is to provide a method and system for decoupling the generation of bridge engineering drawings and BIM models based on data models. First, through a mandatory rule library for drawing representation, the two-dimensional drawing generation process is prohibited from measuring dimensions from the three-dimensional model. Instead, it directly reads and annotates the original design parameter values ​​from the central data source. This enables construction drawings to achieve the same level of accuracy as traditional manual drawing in the BIM automation process for the first time, resolving the core contradiction of "inconsistency between drawings and models" that has long plagued the industry.

[0032] Secondly, this application decouples and parallelizes the model generation and drawing generation processes. Specifically, by splitting the model generation process into independent sub-processes for main beam creation and steel strand generation based on object differences, each process can focus entirely on achieving its optimal algorithm goal without interfering with the others. The 3D model generation can utilize advanced geometric algorithms to pursue geometric accuracy for complex components; the 2D drawing process, based on the same data source, independently applies drafting rules for clear expression. Both processes are unified at the data source, decoupled and parallel in their processes, and achieve optimal results, breaking the inherent contradictions in the traditional "model-driven drawing" paradigm.

[0033] Finally, through innovative SHX font reverse engineering and batch conversion technology, the system can natively use and process engineering standard fonts in non-CAD BIM design environments, and ultimately automatically generate DWG files that fully comply with industry delivery standards. This technology completely liberates designers from tedious post-processing work such as font replacement and format adjustment, enabling BIM design results to be directly applied to existing review, construction, and archiving systems without any manual modifications, thus removing key delivery obstacles to the in-depth application of BIM. Attached Figure Description

[0034] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This application presents a method for decoupling bridge engineering drawings and BIM models based on a data model, and a system architecture diagram within the system.

[0035] Figure 2 This is a schematic diagram in the background technology of a method and system for decoupling bridge engineering drawings and BIM models based on data models, as described in an embodiment of this application.

[0036] Figure 3 This is an overall flowchart of a method for decoupling bridge engineering drawings and BIM models based on a data model, as well as a method within the system, as described in this application.

[0037] Figure 4This application presents a method for decoupling bridge engineering drawings and BIM models based on data models, and a process for generating three-dimensional road centerlines in step S1 of the system.

[0038] Figure 5 This is a schematic diagram of a method for decoupling bridge engineering drawings and BIM models based on a data model, and a schematic diagram of linear data input in step S1 of the system, as described in an embodiment of this application.

[0039] Figure 6 This is a schematic diagram of the drawing frame parameter module in step S1 of a method for decoupling bridge engineering drawings and BIM models based on a data model, as described in an embodiment of this application.

[0040] Figure 7 This is a schematic diagram of a method for decoupling bridge engineering drawings and BIM models based on a data model, and the bridge foundation parameter module in step S1 of the system, as described in an embodiment of this application.

[0041] Figure 8 This is a schematic diagram of a method for decoupling bridge engineering drawings and BIM models based on a data model, and the web thickness parameter module in step S1 of the system, as described in an embodiment of this application.

[0042] Figure 9 This is a schematic diagram of a method for decoupling bridge engineering drawings and BIM models based on a data model, and the cantilever parameter module in step S1 of the system, as described in an embodiment of this application.

[0043] Figure 10 This is a schematic diagram of a method for decoupling bridge engineering drawings and BIM models based on a data model, and the box girder chamfer parameter module in step S1 of the system, as described in an embodiment of this application.

[0044] Figure 11 This is a schematic diagram of a method for decoupling bridge engineering drawings and BIM models based on a data model, and the large span variable height parameter module in step S1 of the system, as described in an embodiment of this application.

[0045] Figure 12 This is a schematic diagram of a method for decoupling bridge engineering drawings and BIM models based on a data model, and the parameter module of the cantilever thickened section in step S1 of the system, as described in an embodiment of this application.

[0046] Figure 13 This is a schematic diagram of the longitudinal prestressed steel strand parameter module of the web in step S1 of a method for decoupling bridge engineering drawings and BIM models based on a data model according to an embodiment of this application.

[0047] Figure 14This is a schematic diagram of a method for decoupling bridge engineering drawings and BIM models based on a data model, and the parameter module for longitudinal prestressed steel strands in the top and bottom slabs in step S1 of the system, as described in an embodiment of this application.

[0048] Figure 15 This is a schematic diagram of a method for decoupling bridge engineering drawings and BIM models based on a data model, and the creation of the top slab model in step S2 of the system, as described in an embodiment of this application.

[0049] Figure 16 This is a schematic diagram of the base plate surface in step S2 of a method for decoupling bridge engineering drawings and BIM models based on a data model, as described in an embodiment of this application.

[0050] Figure 17 This is a schematic diagram of a method for decoupling bridge engineering drawings and BIM models based on a data model, and the construction and assembly steps of parametric details in step S2 of the system, as described in an embodiment of this application.

[0051] Figure 18 This is an example diagram of a method for decoupling bridge engineering drawings and BIM models based on a data model, and an example diagram of the web tendons in the batch generation of prestressed steel strand models in step S2 of the system, as described in an embodiment of this application.

[0052] Figure 19 This is a schematic diagram of the final three-dimensional cylindrical solid model in the S2 step of the system for decoupling bridge engineering drawings and BIM models based on a data model in an embodiment of this application.

[0053] Figure 20 This is a flowchart illustrating a method for decoupling bridge engineering drawings and BIM models based on a data model, and the technical process of converting SHX engineering fonts in step S3 of the system.

[0054] Figure 21 This is an example of a method for decoupling bridge engineering drawings and BIM models based on a data model in this application, and a diagram showing the reconstruction effect of a portion of the text in the complete SHX font library in step S3 of the system.

[0055] Figure 22 This is a comparison diagram of the decoupling generation method of bridge engineering drawings and BIM models based on data models in an embodiment of this application, and the conversion effect of SHX-shaped font text entities in step S3 of the system.

[0056] Figure 23 This is an example of a method for decoupling bridge engineering drawings and BIM models based on a data model, and an interface diagram of the drawing frame matching and output in step S3 of the system.

[0057] Figure 24This is a schematic diagram of a method for decoupling bridge engineering drawings and BIM models based on a data model, and the final DWG file output in step S3 of the system, as described in an embodiment of this application. Detailed Implementation

[0058] The following will refer to the appendix in the examples of this invention. Figures 1-23 The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0059] Example 1: A method and system for decoupling bridge engineering drawings and BIM models based on data models, the overall process steps are as follows: Figure 3 As shown, it is based on the whole-process forward design of concrete box girder bridges with data and expression decoupling.

[0060] This invention uses Rhino 7 as a 3D graphics platform, and leverages its .NET API with C# for secondary development, supplemented by Grasshopper for visual encapsulation of some logic. The system is integrated into Rhino as a plugin. Specifically, it includes the following steps: S1: Construct a central parameterized data source (process A).

[0061] The central parameterized data source of this system consists of two parts working together: 1. Structured Parameter Database: A Microsoft Excel workbook (.xlsx) strictly customized according to a template. This template embeds predefined fields for all design logic and serves as a digital container for design intent.

[0062] 2. Geometric baseline set: A set of reference curves precisely defined in Rhino space, with specific attributes (name, color), used to define complex spatial lines that are difficult to describe with purely numerical parameters.

[0063] Detailed construction of the S1.1 parameter database An Excel workbook contains the following core worksheets, the contents of which are shown in the attached diagram. Figure 6 To be continued Figure 14 As shown: Figure 6 The title block parameter module is used to define the numbering, title number, text height, title number width factor, etc.

[0064] Figure 7 The bridge foundation parameter module is used to define the bridge width range, bridge width, beam height, etc.

[0065] Figure 8 Web thickness parameter module. Figure 9 : Cantilever parameter module. Figure 10 : Chamber chamfering parameter module. Figure 11 Large span variable height parameter module. Figure 12 : Cantilever thickened section parameter module. Defines the detailed dimensions of each part of the box girder.

[0066] Figure 13 The web longitudinal prestressed steel strand parameter module is used to define the geometric information of each prestressed steel strand.

[0067] Figure 14 The top and bottom plate longitudinal prestressed steel strand parameter module is used to define the top and bottom plate strand information.

[0068] S1.2 Input and Standardization of Linear Data In existing technological systems, the horizontal alignment design of roads and bridges is typically completed using specialized alignment design software. To achieve efficient integration, the system adopts the following process: Import: Directly copy and paste the road centerline (set to red), bridge edge line (set to green), web centerline (set to magenta), and cantilever edge line (set to blue) designed in AutoCAD into Rhino software.

[0069] Standardization: In Rhino, all imported curves are placed on the same designated layer (e.g., "00-Input Line"). The system accurately identifies the type and purpose of the curves through their color and layer attributes, and establishes a correlation with the data in the parameter table. The input status is shown in the attached figure. Figure 5 As shown.

[0070] 3D Centerline Generation: Route design typically only provides two-dimensional plane and longitudinal profiles. The system uses an equally spaced point fitting algorithm to automatically generate the 3D road centerline (process shown in the attached diagram). Figure 4 ): Divide the plane line and the longitudinal profile line into control points at the same interval, combine their coordinates (X, Y from the plane, Z from the longitudinal profile) to form a three-dimensional point set, and then fit it into a spatial curve to provide a basis for subsequent three-dimensional modeling.

[0071] At this point, the central data source, including the Excel table and Rhino curves, has been completed.

[0072] Based on the central parametric data source, S2 executes the model generation process and the drawing generation process in parallel and independently. The system then simultaneously and independently begins to execute the following two core processes, which share read access to the central data source but do not depend on any intermediate or final results of the other.

[0073] Process 1: Generation of 3D BIM Model This process strictly adheres to the data source definition, compiling a high-precision 3D model for engineering analysis, quantity calculation, and construction simulation. Core steps include: S2.1.1 Creation of the Main Beam Model To achieve variations in bridge shape, such as curves, widths, and heights, the model was created using a multi-surface splicing technique. This allows for flexible control of the model's appearance while maintaining dimensional accuracy, thus meeting design requirements. The specific steps include: a. Creating the roof model: 1. Input Data Parsing: The system first reads the 3D road centerline (spatial curve), cross slope parameters, and top slab width variation rules from the central parametric data source. These rules are directly linked to the "bridge edge" curve in Rhino, which has been standardized by color (green).

[0074] 2. Generating the Initial "Rough" Surface: To create a continuous base surface that can be used for subsequent precise trimming, the system performs a sweep operation. Specifically, it constructs a cross-sectional profile perpendicular to the road centerline. This profile is dynamically defined based on the cross slope parameters and top slab width rules at the current station. Then, using this cross-sectional profile as the cross section and the 3D road centerline as the path, a single-track sweep is performed to generate a continuous, smooth spatial surface whose width covers all possible design boundaries, i.e., the "initial top slab surface," as shown below. Figure 15 As shown. This step utilizes the conventional sweep function of 3D CAD software, but its core innovation lies in the automation and data-driven generation and input of input parameters (centerline, cross slope, width rules).

[0075] 3. Trimming and Shaping: After obtaining the initial large surface, the system executes the core "surface trimming" operation. It calls commands in Rhino such as Split or Trim, using the green "bridge edge" curve as the precise cutting boundary to trim the initial large surface. This operation directly generates a complex top plate surface that perfectly matches the design lines in three-dimensional space (see appendix for implementation principles and effects). Figure 15 ).

[0076] The value of this method lies in its ability to transform the complex problem of generating variable-width 3D surfaces into a standardized sequence of data-driven, stable geometric operations through a "sweep-then-cut" process, thereby avoiding the misalignment and cumulative errors of seams in traditional segmented modeling methods.

[0077] b. Generation of complex-shaped base plates: For curved bridges with longitudinal slopes and inclined webs, the base plate is a hyperboloid twisted surface. The system employs an innovative algorithm: 1. The system generates a solid or thick surface model representing the web based on the web centerline and slope parameters.

[0078] The system generates a continuous reference surface for the base plate, consistent with the designed longitudinal slope, based on the road's longitudinal slope. This surface has sufficient width in the transverse direction to cover all possible base plate areas.

[0079] 2. Intersection Operation: The system performs a "Model Intersection" Boolean operation to calculate the spatial intersection line between the web model and the base plate surface model. The three-dimensional spatial curve directly obtained from this operation is the precise contour boundary line of the base plate at the web position.

[0080] 3. Contour Lofting to Generate the Final Base Plate: The system acquires the 3D contour boundary lines obtained by the intersection of all web sections, and combines them with the boundary lines at both ends of the bridge. Using the "Loft" or "Mesh to Surface" command, a continuous, smooth base plate surface is generated using these spatial curves as the contour, perfectly matching the geometry and topology of all web models (see Appendix for implementation principle and effect). Figure 16 ).

[0081] This model's intersection and contour lofting method directly solves the precise shape of the base plate that conforms to the geometric constraints of the longitudinal slope and web through geometric calculations. It can effectively solve the technical problem that manual drawing or traditional stretching / sweeping tools cannot accurately construct such complex spatial surfaces.

[0082] c. Construction and assembly of parameterized details: Generation of chamfers inside the box girder: To avoid potential failures or geometric errors during solid Boolean operations on thin-walled box girders, the system employs a construction method based on surface intersection lines. Specifically, the system calculates the extended surfaces of adjacent walls inside the box girder (such as the top plate and web plate) and determines their theoretical intersection lines. Then, using these intersection lines as trimming boundaries or guide lines, chamfered surfaces that meet design dimensional requirements are directly generated through conventional modeling operations such as creating filled surfaces or splicing triangular facets. This method ensures the accuracy and topological stability of the chamfer geometry.

[0083] Parametric assembly of auxiliary components: Components such as beams, diaphragms, and cantilever thickened sections are defined as parametric templates in the system. When the system reads the specific parameters of a component from the data table, it calls the corresponding template, substitutes the parameters, and instantiates the 3D geometry of the component. Subsequently, based on the geometric constraints defined in the data table or built-in logic, the system automatically and precisely assembles the instantiated component into the designated position on the main beam body through coordinate transformation and alignment operations. See the appendix for various variation forms. Figure 17 As shown in the figure, this process enables fully automated mapping from design parameters to 3D assemblies.

[0084] S2.1.2 Batch generation of prestressed steel strand models The system executes a pre-defined, modular algorithm chain to generate solid models of each prestressed steel strand in batches using a parameter-driven approach. Taking a web strand as an example, the chained process is as follows (see appendix). Figure 18 ): Projection: Project the two-dimensional planar layout lines of the steel strands onto the inner surface of the top or bottom plate of the already generated box girder.

[0085] Vertical offset: The projection line is shifted along the Z-axis (vertical) to the height position specified on the design drawing.

[0086] Control point insertion and segmentation: Insert control points at key locations such as the start and end of vertical curves, and use them to segment the spatial curve.

[0087] Rounding and Reconstruction: Rounding is performed on the curves between the split points to simulate the smooth bending shape of the steel strands. Then, the curves are merged back into a continuous spatial path.

[0088] Solidification: Using the spatial path as the scanning trajectory and the nominal diameter of the steel strand as the circular cross-section, a scanning operation is performed to generate the final three-dimensional cylindrical solid model, such as... Figure 19 As shown, the prestressed duct is accurately characterized.

[0089] S2.2 Two-Dimensional Construction Drawing Generation Process S2.2.1 Rule-Driven Direct Drawing At the heart of this process is an embedded, extensible "cartographic representation rule base." This rule base is essentially a series of predefined mapping rules that specify how to directly convert structured parameters and geometric datums from a central parametric data source into a two-dimensional drawing symbol system that conforms to national standards such as the "Road Engineering Drawing Standard," rather than deriving views from a three-dimensional model.

[0090] As an example of implementing the present invention, the generation of the cross-sectional view is as follows: When it is necessary to generate the cross-sectional view of the box girder at station K10+100, the system performs the following specific steps: Data location and extraction: Based on the target station number K10+100, the system locates the corresponding data row in the corresponding parameter table of the central parameterized data source.

[0091] Parameter reading: Directly read a series of predefined design parameters in this row, such as "top slab full width" (cell value is 21.75), "beam height", "web thickness", "bottom slab thickness", and "cantilever length".

[0092] Two-dimensional graphic construction: The system uses these read values ​​to execute two-dimensional drawing commands in Rhino's two-dimensional drawing space: draw a horizontal top plate line with a width of 21.75 meters; draw a vertical construction line downwards according to the "beam height" value; combine parameters such as "web thickness" and "bottom plate thickness" to calculate the two-dimensional coordinates of each point inside the box girder, and connect them with straight lines or arcs to draw the standard box girder cross-sectional outline.

[0093] Dimensioning: Add dimensions to the completed outline. The dimension text is the original design value read in the previous step, for example, "21.75m" in the width direction. From this point on, regardless of whether the section is located on a straight or curved segment, its dimension value will always be the design value of 21.75m, fundamentally eliminating the dimension distortion problem caused by oblique cutting from a 3D curved surface model.

[0094] S2.2.2 Intelligent optimization and automatic map generation of map elements To ensure the professionalism and readability of the generated drawings, this process integrates an intelligent processing module for annotation conflicts and drawing layout.

[0095] (1) Intelligent avoidance of annotations and text: The system performs conflict detection and adjustment in real time when creating annotations. Specific rules include: Bounding box interference check: The system calculates the area (bounding box) occupied by the newly labeled text box and leader line, and compares its position with the bounding boxes of existing elements on the drawing.

[0096] Rule-driven automatic adjustment: When overlap is detected, the system automatically performs adjustments based on preset priorities. For example, it automatically extends the leader line of a "beveled dimension" or moves its text position until the conflict is resolved. For dense, continuous dimensions, the system can automatically place the dimension text alternately above and below the dimension line to avoid overlap.

[0097] (2) Automated layout and output of multiple views: The system provides a complete "one-click image generation" framework. When a user triggers this function through the main interface, the system executes the following automated steps: View generation and collection: Based on the user's selection, the system calls the corresponding drawing module (such as the general construction drawing module and the steel strand drawing module) to generate all independent two-dimensional views (plan view, elevation view, multiple cross-section views, etc.) in the Rhino model space.

[0098] Automatic layout: The system treats all views as a set and automatically lays them out using a grid-based constraint algorithm based on the user-specified drawing size (e.g., A1) and global output scale. This algorithm calculates the appropriate size and position for each view, ensuring correct logical relationships between views, neat arrangement, and consistent spacing.

[0099] Title Frame Matching and Output: After layout is complete, the system automatically matches and fits the standard title frame, placing the content of each view into the corresponding viewport within the title frame. Finally, users can use the "Print / Export" function to generate a formatted PDF file with one click, or proceed to the subsequent dedicated font conversion process to generate a DWG file (see attached instructions). Figure 22 and 23 ).

[0100] S3. Post-processing and Standardized Output After generating the original 3D model and 2D drawing data independently, the system enters the final deliverable processing stage. The core task of this stage is to automatically and losslessly convert the intermediate deliverables from the native design environment into high-quality final documents that meet industry-standard delivery criteria, especially overcoming the key obstacles in integrating BIM deliverables with traditional CAD workflows.

[0101] S3.1SHX Project Font Conversion To address the industry pain point of the inability to natively use AutoCAD's proprietary SHX line font in BIM design environments, which necessitates extensive manual font replacement before drawing delivery, this invention implements a fully automated, high-fidelity font conversion pipeline. The technical process is attached. Figure 20 As shown, the specific steps are as follows: S3.1.1 Reverse Engineering and Reconstruction of Font Library: During the system development phase, a separate tool program is used to reverse-parse the target AutoCAD .shx font files (such as Simplex and Hztxt.shx commonly used in engineering) and convert them into readable .shp definition text files.

[0102] Develop a dedicated Rhino font rendering engine. This engine can parse vector drawing instructions (such as moving, drawing lines, and drawing arcs) in .shp files and, within the Rhino environment, precisely "draw" the outline of each character using its native geometry (straight lines, arcs, polylines), thereby reconstructing a complete SHX font library within Rhino (see appendix for some character reconstruction results). Figure 21 ).

[0103] S3.1.2 Synchronization markers during the drawing process: When any text is drawn in Rhino during the drawing generation process, the font rendering engine is immediately invoked to generate a graphic of that text composed of curves.

[0104] At the same location where the curved text graphic is generated, the system simultaneously creates an invisible, non-printable point object as a "marker". The name attribute of this point object is set to a structured string that encodes all the key information of the original text, such as: TEXT|21.75m|Simplex|3.5|0.7, whose meanings are, in order: type flag, text content, target SHX font name, design font height, and width factor.

[0105] S3.1.3DWG file conversion: When a user needs to export AutoCAD DWG format drawings, the system executes a predefined automated script: a. Step 1: Intermediate File Generation: The script first temporarily deletes all SHX text graphics composed of curves in the current Rhino file. Then, it reads all the "marker" point objects in the file and, based on their recorded attributes (content, font height, position), recreates a batch of Rhino text objects using the Windows system's universal font at exactly the same locations. Next, it exports this Rhino file as an intermediate DWG file. At this point, the text in the DWG file is editable, but the font is Arial, which does not conform to engineering standards.

[0106] b. Step Two: Batch Font Replacement: The user opens the dedicated conversion plugin provided with this invention in AutoCAD software. By entering the command UNIFIEDFORMAT and selecting the _Intermediate.dwg file generated in the previous step, the plugin begins to work. It automatically traverses all Arial font text in the file, matches its coordinate position with the "marker" point object information, and then accurately and in batches replaces it with the specified, actual SHX-shaped font text entities (see the appendix for a comparison of conversion effects). Figure 22 ).

[0107] S3.2 Integration and Output of Final Results After the above post-processing, the system synchronously generates and outputs a complete, consistent, and directly deliverable design deliverable package: 3D BIM Model File: Outputs a high-precision 3D model file (such as Rhino's native .3dm format or the industry standard .ifc format). This model is geometrically accurate, contains complete component information, and can be directly used for structural analysis, automatic quantity surveying, 3D collision detection, construction progress simulation, etc.

[0108] Two-dimensional construction drawing files: PDF files: Generated directly from Rhino layouts optimized for printing, suitable for electronic distribution, printing, or archiving.

[0109] DWG files: AutoCAD files generated through the font conversion pipeline described above, fully compliant with Chinese engineering drawing standards. All layers, line types, colors, and fonts within the file meet the delivery requirements of the target company or project, and the drawings can be directly used for construction briefings, printing, or inclusion in traditional drawing management systems.

[0110] Central parametric data source file: An Excel spreadsheet (.xlsx) or database export file that serves as the root of all results. This file records all design parameters and logic, and is the sole authoritative record of design intent, facilitating design change tracking, version management, and parametric reuse in similar projects.

[0111] Through this step, the present invention not only realizes the automated generation of models and drawings, but also ensures that the generated results can be seamlessly integrated into the existing standardized workflow of engineering design and construction, completing a closed loop from innovative design methods to practical productivity.

Claims

1. A method for decoupling the generation of bridge engineering drawings and BIM models based on data models, characterized in that, Includes the following steps: S1: Construct a central parametric data source, which is used to structure and store all design parameters and geometric reference information of the bridge project; S2: Based on the central parametric data source, the model generation process and the drawing generation process are executed in parallel and independently; The model generation process includes: the main beam model creation process and the prestressed steel strand model generation process; The main beam model creation process includes: a sub-process for generating a variable-width top plate, a sub-process for generating a complex-shaped bottom plate, and a sub-process for parametric detailed construction and assembly. The drawing generation process includes: based on the data source and a rule library that stipulates that drawing annotation values ​​must be directly adopted from the design parameters in the data source and prohibits measurement from the geometry of the 3D BIM model, drawing outline graphics directly in the 2D drawing space and generating annotations, thereby generating 2D construction drawings; S3: Post-process the graphic files output by the drawing generation process to generate the final delivered drawing files.

2. The method for decoupling bridge engineering drawings and BIM models based on a data model according to claim 1, characterized in that, The variable-width roof slab generation sub-process is executed as follows: an initial surface is generated by sweeping based on the road centerline and cross slope parameters; the initial surface is then trimmed using the bridge edge space curve obtained from the data source to obtain the roof slab model.

3. The method for decoupling bridge engineering drawings and BIM models based on a data model according to claim 1, characterized in that, The complex-shaped base plate generation sub-process executes as follows: generating a web plate model and a base plate reference surface model; calculating the spatial intersection line between the web plate model and the base plate reference surface model to obtain the base plate outline; and generating a base plate curved surface model based on the base plate outline.

4. The method for decoupling bridge engineering drawings and BIM models based on a data model according to claim 1, characterized in that, The parametric detailed construction and assembly sub-process execution is as follows: For the chamfer inside the box, it is constructed by calculating the intersection line of adjacent walls and splicing triangular facets; for the auxiliary components of beams and diaphragms, they are instantiated by calling parametric templates and automatically assembled to the main beam body according to geometric constraints.

5. The method for decoupling bridge engineering drawings and BIM models based on a data model according to claim 1, characterized in that, The prestressed steel strand model generation process executes the following chain of operations: projecting the two-dimensional arrangement line of the steel strands onto the surface of the box girder; offsetting it vertically to the design height; inserting control points at the bending points and dividing the curves; performing rounding corner processing; merging the curves and assigning circular cross-sections to generate a three-dimensional solid pipe model.

6. The method for decoupling bridge engineering drawings and BIM models based on a data model according to claim 1, characterized in that, In the drawing generation process, when generating the bridge cross-section drawing, the following steps are performed: extract the design parameter values ​​of the full width of the top slab and the beam height from the data source according to the target station number; The two-dimensional cross-sectional outline is directly constructed using the design parameter values; the outline is then dimensioned according to the design parameter values.

7. The method for decoupling bridge engineering drawings and BIM models based on a data model according to claim 1, characterized in that, The post-processing step S3 includes engineering font conversion processing: S31: In the drawing generation process, when creating graphic text, a marker object containing the text attribute information is generated simultaneously. S32: Export the intermediate graphic file containing the marked object to an intermediate format file; S33: Load the conversion program in the target CAD platform and, based on the attribute information of the marked object, batch replace the text in the intermediate format file with standard engineering font entities.

8. A system for decoupling bridge engineering drawings and BIM models based on a data model, used to implement the method described in any one of claims 1-7, characterized in that, include: The data management module is used to build and maintain the central parameterized data source; The model generation module is used to execute the model generation process; The drawing generation module integrates the rule base and is used to execute the drawing generation process; The output processing module is used to perform the post-processing steps.

9. A system for decoupling bridge engineering drawings and BIM models based on a data model, as described in claim 8, is characterized in that... The drawing generation module includes an intelligent avoidance submodule, which is used to perform the drawing optimization steps; the output processing module includes a font conversion submodule, which is used to perform engineering font conversion processing.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 1-7.

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