Three-dimensional special-shaped formwork construction design method based on BIM modeling technology

Abstract

The present application relates to the field of building engineering BIM construction technology, specifically to a three-dimensional special-shaped formwork construction design method based on BIM modeling technology, comprising: obtaining a full-professional deepening design model of a to-be-constructed component, extracting three-dimensional geometric boundary and steel bar arrangement information of the special-shaped component, inversely reconstructing a complete outer surface digital model and correlating steel bar line frame information. Combining formwork assembly rules and demolding feasibility, template unit blocks are automatically divided, initial demolding lines are generated, after mapping steel bar information, the spatial interference between the demolding lines and the steel bars is detected, the final demolding lines are automatically adjusted to avoid interference, template three-dimensional panel models are generated based on the final demolding lines and spatial positioning coordinates are calculated. This method realizes the automatic optimization design of special-shaped formwork blocks and demolding lines, adapts to the spatial arrangement constraints of steel bars, and meets the spatial layout requirements of special-shaped component construction.

Description

Technical Field

[0001] This invention relates to the field of BIM construction technology in building engineering, and in particular to a three-dimensional irregular formwork construction design method based on BIM modeling technology. Background Technology

[0002] Traditional three-dimensional irregular concrete component formwork design relies primarily on two-dimensional construction drawings. The formwork is broken down into sections based on manual experience, and parting lines are manually drawn. In some BIM-enabled scenarios, only the component model is visualized, without integrating formwork assembly rules and demolding feasibility into the model's sectioning logic. During construction, the spatial verification of internal reinforcement layout information against the formwork parting lines is done manually, comparing the reinforcement drawings and formwork parting line drawings segment by segment. Adjustments to the parting line positions are also made manually.

[0003] Manually dividing the template into units cannot simultaneously adapt to the template assembly rules and demolding feasibility requirements. The shape and boundary division of the blocks are arbitrary, the accuracy of the initial parting line drawing is limited by manual operation, and the boundary information is not fully recorded. Manually checking the spatial interference between the reinforcement and the parting line results in the omission of interference points. Manually adjusting the parting line cannot accurately match the spatial arrangement constraints of the reinforcement, and the spatial conflict between the parting line and the reinforcement arrangement is difficult to eliminate.

[0004] It is necessary to automatically divide the template unit into blocks and generate preliminary parting lines by combining the template assembly rules and demolding feasibility. It is also necessary to automatically detect and avoid interference of parting lines under the spatial line frame mapping of steel bars, and eliminate various construction adaptation defects caused by manual operation. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a three-dimensional irregular formwork construction design method based on BIM modeling technology.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a three-dimensional irregular formwork construction design method based on BIM modeling technology, comprising: Obtain the full-discipline detailed design model of the component to be constructed, and extract the three-dimensional geometric boundary information and internal reinforcement arrangement information of the target irregular concrete component from the full-discipline detailed design model; Based on the three-dimensional geometric boundary information, the complete outer surface digital model of the target irregular concrete component is reconstructed in reverse, and the internal steel reinforcement arrangement information is associated with the complete outer surface digital model in the form of a spatial wireframe. The construction process of the complete outer surface digital model is analyzed. Based on the preset template assembly rules and demolding feasibility, multiple template unit blocks are automatically divided on the complete outer surface digital model, and preliminary parting lines that record the boundary information of each template unit block are generated. The internal steel reinforcement arrangement information is mapped to the digital model of the complete outer surface after the initial parting, the spatial interference between the steel reinforcement and the initial parting line is detected, and the initial parting line that causes spatial interference is automatically avoided and adjusted to form the optimized final parting line. Based on the final parting line, the complete outer surface digital model is segmented to generate a template three-dimensional panel model corresponding to each template unit block, and the spatial positioning coordinates of each template three-dimensional panel model are automatically calculated according to the three-dimensional geometric boundary information.

[0007] As a further aspect of the present invention, based on the three-dimensional geometric boundary information, a complete digital model of the outer surface of the target irregular concrete component is reconstructed in reverse, including: Read the point cloud data set, geometric cross-sectional contour line set, and surface control parameter set contained in the three-dimensional geometric boundary information; Using the point cloud data set and the geometric cross-sectional contour line set, a preliminary surface model of the target irregular concrete component is reconstructed through a non-uniform rational B-spline surface fitting algorithm. The smoothness and continuity of the preliminary surface model are optimized and verified based on the set of surface control parameters to ensure that the surface transition is smooth and there is no self-intersection. Extract all boundary edges of the preliminary surface model, and enclose the preliminary surface model into a solid model through boundary edge extension and stitching operations. The outer surface of the solid model is the complete outer surface digital model.

[0008] As a further aspect of the present invention, a construction process analysis is performed on the complete outer surface digital model. Based on preset template assembly rules and demolding feasibility, multiple template unit blocks are automatically divided on the complete outer surface digital model, including: The preset template standard size library and maximum transportable size constraints are used to determine the maximum allowable planar projected area and maximum allowable side length of a single template unit block; In the complete digital model of the outer surface, continuous regions with similar curvature characteristics are identified, and these continuous regions are marked as candidate segmentation regions; Based on the maximum allowable planar projected area and the maximum allowable side length, the candidate segmentation region is recursively segmented until each segmented sub-region satisfies the size constraints, and each sub-region corresponds to a template unit block; While segmenting, the center normal vector of each template unit block is calculated, and the angle between the center normal vector and the preset demolding direction is checked. Segmentation schemes with angles exceeding the preset allowable angle threshold are eliminated. With the optimization objectives of minimizing the total length of the dividing line and the number of template unit block types, the optimal scheme is selected from all the dividing schemes that satisfy the size and demolding direction constraints, and the dividing line in the optimal scheme is defined as the preliminary parting line.

[0009] As a further aspect of the present invention, the automatic avoidance adjustment of the preliminary parting line that causes spatial interference to form an optimized final parting line includes: Establish a three-dimensional cylindrical envelope model for each steel bar in the internal steel bar arrangement information; Calculate the minimum distance between the virtual segmentation surface defined by the initial parting line and all the three-dimensional cylindrical envelope models; When the minimum distance is less than the preset safe clearance threshold, it is determined that the preliminary parting line and the reinforcing bar are spatially interfering. For the initial parting line segment where spatial interference occurs, a new feasible path is searched along the curved surface of the complete outer surface digital model within a preset adjustment distance range. The new feasible path must ensure that the minimum distance to the envelope model of all steel reinforcement three-dimensional cylinders is greater than the safe net distance threshold, and does not violate the process constraints of the template unit segmentation. The original initial parting line segment that caused spatial interference is replaced by the new feasible path found, thereby completing the adjustment of all parting lines and forming the final parting line that does not conflict with the reinforcing bars.

[0010] As a further aspect of the present invention, based on the final parting line, the complete outer surface digital model is segmented to generate a template three-dimensional panel model corresponding to each template unit block, including: Using the final parting line as the boundary, the complete outer surface digital model is discretized into multiple independent surface pieces, each surface piece corresponding to the casting contact surface of a template unit block; For each of the curved surface patches, with its edge as the baseline, it is offset equidistantly in the normal direction to the outside of the concrete member to generate a template solid panel with a thickness equal to the template design thickness. At the edge of the template solid panel, three-dimensional features of the back rib groove and connection hole are automatically generated according to the preset back rib arrangement rules. The template solid panel with the back rib groove and connection hole is generated and combined with its corresponding original curved surface piece, and a unique template number is assigned to it, thus generating the template three-dimensional panel model. All the three-dimensional panel models of the templates under the same concrete component are assembled into a whole three-dimensional irregular template group model according to their spatial position relationship.

[0011] As a further aspect of the present invention, it also includes a step of deepening the construction of each template three-dimensional panel model: From the preset connector library, obtain three-dimensional models of connecting bolts and tie rods that match the back groove and connecting hole positions according to the standard. On the non-contact surface of the template 3D panel model, based on the structural stress calculation results, the 3D models of stiffening ribs and vertical main ribs are automatically laid out, and it is ensured that there is no geometric conflict between the stiffening ribs and the template solid panel and the back rib groove. Calculate the required standard profile length and specifications for each of the aforementioned connecting bolts, tie rods, stiffening ribs, and vertical main ribs, and generate the corresponding material list; Three-dimensional markers for on-site assembly are added to the edges of the template's three-dimensional panel model, including alignment and numbering marks.

[0012] As a further aspect of the present invention, it also includes a step of simulating the construction process based on an overall three-dimensional irregular template group model: In the 3D simulation environment, the 3D panel model of each template and its associated connecting bolts, tie rods, stiffening ribs and vertical main ribs are called in sequence; According to the preset standard construction procedures, the movement path, rotation action and assembly sequence of the model components are defined. The standard construction procedures include template transportation, on-site hoisting, temporary fixing, positioning, final connection and overall verification. Drive all relevant models to move in the defined order and path to simulate the entire process of assembling a three-dimensional irregular template on site; During the simulation, spatial collisions between motion models and between motion models and fixed permanent structure models are detected in real time, and the location and time of the collision are recorded. Based on the simulation and collision detection results, a construction simulation result containing animations of standard assembly procedures and potential risk warning reports is generated.

[0013] As a further aspect of the present invention, it also includes the step of optimizing material cutting and processing based on construction simulation results: The construction simulation results were analyzed, and the frequency and number of occurrences of the same type and specifications of the template 3D panel model, connecting bolts, tie rods, stiffening ribs and vertical main ribs were statistically analyzed. Integrate the aforementioned material cutting lists, merge the material requirements of the same specifications, and generate a total material procurement list and a categorized material cutting list; Based on the geometric dimensions and surface curvature of the template 3D panel model, a cutting path code suitable for CNC cutting equipment is automatically generated; Based on the three-dimensional model of the stiffening rib and the vertical main rib, the machining details and hole positioning diagram are automatically generated. The total material procurement list, categorized cutting list, cutting path code, processing details and hole positioning diagram are packaged and output as a digital processing file package for factory prefabrication.

[0014] As a further aspect of the present invention, obtaining the full-discipline detailed design model of the component to be constructed includes: Obtain design models from multiple disciplines, including architecture, structure, and mechanical and electrical engineering, that contain the target irregularly shaped concrete component; Perform geometric consistency checks and conflict detections on the design models of the architecture, structure, and mechanical and electrical engineering disciplines. Based on the detection results, coordinate system alignment, geometric position alignment, and missing information repair were performed on the design models of the multiple disciplines. From the design models of multiple disciplines that have completed coordinate system one, geometric position alignment and missing information repair, extract and integrate the geometric information of structural components, the layout information of steel bars, the positioning information of embedded parts and the spatial constraint information of adjacent components. Generate a single data model containing the geometric information of the structural components, the arrangement information of the reinforcing bars, the positioning information of the embedded parts, and the spatial constraint information of the adjacent components. The single data model is the full-discipline detailed design model. In the comprehensive professional detailed design model, the geometric boundaries, internal reinforcement, and relationships of the target irregular concrete component and its surrounding related components have all been expressed in three dimensions and associated with data.

[0015] As a further aspect of the present invention, using the point cloud data set and the geometric cross-sectional contour line set, a preliminary surface model of the target irregular concrete component is reconstructed through a non-uniform rational B-spline surface fitting algorithm, including: The point cloud dataset is denoised and processed to obtain a feature point cloud dataset; The geometric cross-sectional contour line set is smoothed and repaired to obtain continuous closed cross-sectional contour lines; Using the feature point cloud set as the surface shape control points and the continuous closed cross-sectional contour line as the cross-sectional guide line, a control mesh for a non-uniform rational B-spline surface fitting algorithm is constructed. Based on the control mesh, the surface generation calculation module of the non-uniform rational B-spline surface fitting algorithm iteratively calculates the preliminary surface control point matrix and node vector sequence that satisfy the spatial position constraints of the feature point cloud set and the orientation constraints of the continuous closed cross-sectional contour line. Based on the preliminary surface control point matrix, node vector sequence, and preset surface order, a mathematical expression for a non-uniform rational B-spline surface is generated. Based on the mathematical expression of the non-uniform rational B-spline surface, a continuous and differentiable surface model is reconstructed in the three-dimensional modeling space. The surface model is the preliminary surface model of the target irregular concrete component.

[0016] Compared with the prior art, the advantages and positive effects of the present invention are as follows: Based on the 3D geometric boundary information of the target irregular concrete component, a complete digital model of the outer surface is reconstructed. The internal reinforcement arrangement information is then linked to the complete digital model of the outer surface in the form of a spatial wireframe. Combining preset template assembly rules and demolding feasibility, multiple template unit blocks are automatically divided on the complete digital model of the outer surface. Preliminary parting lines recording the boundary information of each template unit block are generated simultaneously. The template block division logic conforms to the construction process parameters, the boundary information of the preliminary parting lines corresponds one-to-one with the template unit blocks, the block layout matches the spatial requirements of the demolding operation, the generated form of the parting lines matches the geometric features of the component's outer surface, the completeness of the parting line boundary records is superior to the manual drawing mode, and the rationality of the template block division is not affected by differences in human experience.

[0017] The internal rebar layout information is mapped onto the complete external surface digital model after the initial formwork separation. Interference between the rebar and the initial formwork line is automatically identified through spatial position comparison. Automatic avoidance adjustments are performed on the initial formwork line where spatial interference exists, resulting in an optimized final formwork line. All spatial interference points between the rebar and the formwork line can be fully identified. The avoidance adjustment path of the formwork line conforms to the layout constraints of the rebar spatial frame. The spatial position of the final formwork line has no spatial conflict with the rebar layout. The formwork line adjustment result forms a coordinated and adaptive relationship with the internal rebar layout of the component. The accuracy and comprehensiveness of interference point processing are superior to manual adjustment. The spatial adaptation state of the formwork line and the rebar stably conforms to the spatial layout requirements of the construction model. Attached Figure Description

[0018] Figure 1 This is a flowchart of the three-dimensional irregular formwork construction design method based on BIM modeling technology described in this invention; Figure 2 A flowchart for construction process analysis and automatic template unit segmentation method; Figure 3 Comparison chart of key parameters before and after adjusting the BIM template parting line; Figure 4 A graph showing the correlation between construction time and completion rate of 3D irregular formwork construction design based on BIM; Figure 5 This is a diagram showing the planar unfolding and CNC cutting path of an irregular curved surface template. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] In the description of this invention, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, in the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0021] See Figure 1 This invention provides a method for monitoring and diagnosing computer motherboard faults, the specific method including: A comprehensive detailed design model of the component to be constructed is obtained, and the three-dimensional geometric boundary information and internal reinforcement arrangement information of the target irregular concrete component are extracted from the comprehensive detailed design model. Based on the extracted three-dimensional geometric boundary information, the complete external surface digital model of the target irregular concrete component is reconstructed in reverse, and the internal reinforcement arrangement information is associated with the complete external surface digital model in the form of a spatial wireframe. Construction process analysis is performed on the reconstructed complete external surface digital model. According to the preset template assembly rules and demolding feasibility, multiple template unit blocks are automatically divided on the model, and preliminary parting lines recording the boundary information of each template unit block are generated. The internal reinforcement arrangement information is mapped to the complete external surface digital model after preliminary parting, and the spatial interference between the reinforcement and the preliminary parting lines is detected. Preliminary parting lines with spatial interference are automatically adjusted to avoid them, forming optimized final parting lines. Based on the final parting lines, the complete external surface digital model is segmented to generate a template three-dimensional panel model corresponding to each template unit block, and the spatial positioning coordinates of each template three-dimensional panel model are automatically calculated based on the three-dimensional geometric boundary information.

[0022] In one embodiment of the present invention, a design model encompassing multiple disciplines, including architecture, structure, and MEP (Mechanical, Electrical, and Plumbing), is obtained. Geometric consistency checks and conflict detection are performed on the design models of these disciplines. Based on the detection results, coordinate system alignment, geometric position alignment, and missing information repair are performed on the design models of these disciplines. From the design models of these disciplines that have completed coordinate system alignment, geometric position alignment, and missing information repair, geometric information of structural components, reinforcement arrangement information, embedded part positioning information, and spatial constraint information of adjacent components are extracted and integrated. A single data model containing the geometric information of the structural components, the reinforcement arrangement information, the embedded part positioning information, and the spatial constraint information of adjacent components is generated. This single data model is the comprehensive detailed design model. In the comprehensive detailed design model, the geometric boundaries, internal reinforcement, and relationships of the target irregular concrete component and its surrounding related components are all expressed in three dimensions and associated with data.

[0023] In practice, architectural, structural, and mechanical and electrical (MEP) design models of the target irregularly shaped concrete component are acquired. In some embodiments, the architectural design model is completed by the architect in building information modeling (BIM) software, including the component's decorative outline, functional zoning, and spatial positioning information. The structural design model is completed by the structural engineer in structural design software, including the component's precise geometry, material properties, reinforcement details, and load information. The MEP design model is completed by the MEP engineer in pipeline integration software, including information on pipelines, equipment, and embedded sleeves that pass through or are adjacent to the component.

[0024] In practice, geometric consistency checks and conflict detection are performed on the architectural, structural, and mechanical / electrical engineering (MEP) design models. Geometric consistency checks verify whether the descriptions of the spatial location and geometric dimensions of the same component are consistent across different professional models. Conflict detection analyzes whether there are unreasonable overlaps, intersections, or insufficient spacing between components, pipelines, and equipment in three-dimensional space across different professional models. Based on the detection results, coordinate system 1, geometric alignment, and missing information repair are performed on the design models of multiple professional disciplines. Coordinate system 1 transforms all professional models to the same project coordinate system. Geometric alignment is based on the structural design model, adjusting the positions of related components in the architectural and MEP design models. Missing information repair supplements and re-links lost information such as component identifiers, material grades, and version numbers transmitted between models.

[0025] In some embodiments, geometric information of structural components, reinforcement arrangement information, embedded part positioning information, and spatial constraint information of adjacent components are extracted and integrated from design models of multiple disciplines that have completed coordinate system one, geometric position alignment, and missing information repair. Optionally, the geometric information of structural components includes control point coordinates, surface equations, and boundary conditions; the reinforcement arrangement information includes reinforcement type, three-dimensional spatial orientation, bending point coordinates, and protective layer thickness; the embedded part positioning information includes the three-dimensional coordinates and orientation of embedded steel plates, sleeves, and bolts in the component; and the spatial constraint information of adjacent components includes the support boundary of the completed structure for the target component, construction joint location, and post-cast strip range. It is understood that the extraction of the above information depends on the model data interface and the reading rules of the custom attribute set.

[0026] A single data model is generated, containing geometric information of structural components, reinforcement arrangement information, embedded part positioning information, and spatial constraint information of adjacent components. This single data model is the comprehensive detailed design model. The single data model is stored in a neutral file format, such as an industry-standard format, and its internal data structure ensures that the topological relationships and attribute associations between various types of information are preserved. Optionally, in the comprehensive detailed design model, the geometric boundaries, internal reinforcement, and relationships of the target irregular concrete component and its surrounding components are all represented in three dimensions and associated with data. This association is manifested as a two-way link between geometric entities and attribute data, as well as the definition of spatial relationships between components. It can be understood that the generation process of the comprehensive detailed design model involves data extraction, transformation, and loading operations. Its logic can be expressed as a quantitative indicator of the model's information fusion degree, calculated using the following formula:

[0027] in: Indicates the first Information integration score for each component Indicates the total number of associated information categories. Indicates the first The weighting coefficient of class information in the fusion evaluation Indicates the first The first component Data integrity and consistency score for class information.

[0028] In one embodiment of the present invention, a set of point cloud data, a set of geometric cross-sectional contour lines, and a set of surface control parameters contained in the three-dimensional geometric boundary information are read. The point cloud data is denoised and processed to obtain a set of feature point clouds. The set of geometric cross-sectional contour lines is smoothed and repaired to obtain continuously closed cross-sectional contour lines. Using the set of feature point clouds as surface shape control points and the continuously closed cross-sectional contour lines as cross-sectional guide lines, a control mesh for a non-uniform rational B-spline surface fitting algorithm is constructed. Based on the control mesh, the surface generation calculation module of the non-uniform rational B-spline surface fitting algorithm iteratively calculates the preliminary surface control point matrix and node vector sequence that satisfy the spatial position constraints of the feature point cloud set and the orientation constraints of the continuously closed cross-sectional contour lines. Based on the preliminary surface control point matrix, node vector sequence, and preset surface order, a mathematical expression for the non-uniform rational B-spline surface is generated. Based on the mathematical expression of the non-uniform rational B-spline surface, a continuous and differentiable surface model is reconstructed in the three-dimensional modeling space. This surface model serves as the preliminary surface model of the target irregular concrete component. The smoothness and continuity of this preliminary surface model are optimized and verified according to the set of surface control parameters to ensure smooth surface transitions and the absence of self-intersections. All boundary edges of the preliminary surface model are extracted, and through boundary edge extension and stitching operations, the preliminary surface model is enclosed into a solid model. The outer surface of this solid model is the complete digital model of the outer surface.

[0029] In practice, the point cloud data set, geometric section contour line set, and surface control parameter set contained in the three-dimensional geometric boundary information are read. The point cloud data set comes from the three-dimensional laser scan of existing similar structures and contains the coordinates of millions of spatial points. The geometric section contour line set comes from the component cross-sectional contours taken from different elevation positions in the structural design drawings. The surface control parameter set contains the design requirements parameters for surface smoothness and curvature continuity.

[0030] In practical implementation, the point cloud dataset is denoised and processed to obtain a feature point cloud set. The denoising process employs a statistical outlier removal algorithm to filter out discrete noise points that deviate from the main point cloud cluster beyond a set threshold. Processing operations include downsampling the point cloud to reduce data volume, while a feature edge detection algorithm is used to retain point clouds that characterize component edges and corners, forming a feature point cloud set. The geometric cross-sectional contour set is smoothed and repaired to obtain continuous, closed cross-sectional contour lines. The smoothing process uses a spline curve fitting algorithm to eliminate jagged jitter generated during digitization. The repair process connects broken line segments and closes non-closed contours, ensuring that each cross-sectional contour line is a continuous and closed spatial curve.

[0031] In specific implementations, a control mesh for the non-uniform rational B-spline surface fitting algorithm is constructed using a feature point cloud set as the surface shape control points and a continuously closed cross-sectional contour line as the cross-sectional guide line. In some embodiments, the control mesh is constructed by triangulating the feature point cloud according to spatial proximity to form an initial mesh, then projecting the continuously closed cross-sectional contour line onto this initial mesh, and adjusting the mesh nodes so that the edges of the mesh are consistent with the direction of the cross-sectional contour line. Based on the control mesh, the surface generation calculation module of the non-uniform rational B-spline surface fitting algorithm iteratively calculates the initial surface control point matrix and node vector sequence that satisfy the spatial position constraints of the feature point cloud set and the direction constraints of the continuously closed cross-sectional contour line. The iterative process minimizes the distance between the fitted surface and the feature point cloud set, while ensuring that the surface cross-sectional line is tangent to the continuously closed cross-sectional contour line at corresponding positions.

[0032] In specific implementation, a mathematical expression for a non-uniform rational B-spline surface is generated based on the preliminary surface control point matrix, node vector sequence, and preset surface order. Optionally, the preset surface order is set to 3 in both the U and V parameter directions to achieve curvature continuity. Based on the mathematical expression of the non-uniform rational B-spline surface, a continuous and differentiable surface model is reconstructed in the 3D modeling space. This surface model is the preliminary surface model of the target irregular concrete component. In some embodiments, the reconstruction process is implemented by calling the surface generation function of the 3D modeling kernel, converting the mathematical expression into a visual boundary representation model.

[0033] In practice, the initial surface model is optimized for smoothness and its continuity is verified based on the set of surface control parameters. Smoothness optimization is achieved by adjusting the weight factors of a small number of control points in the initial surface control point matrix to eliminate unnecessary fluctuations in the surface within the parameter domain. Continuity verification checks whether the positional continuity, tangent continuity, and curvature continuity of the initial surface model at the splicing boundaries meet the set values ​​in the surface control parameter set, ensuring a smooth surface transition without self-intersection. Optionally, the absence of self-intersection is verified by calculating the directional consistency of the surface normal vector.

[0034] In practical implementation, all boundary edges of the preliminary surface model are extracted. Through boundary edge extension and stitching operations, the preliminary surface model is enclosed into a solid model. It can be understood that the boundary edge extension operation extends the unconnected open boundaries in the preliminary surface model along their tangent directions until they intersect with another boundary or extend to a specified plane. The stitching operation geometrically merges the intersecting boundaries after extension, or multiple surface patches of the preliminary surface model itself, at a shared edge, forming a closed three-dimensional solid with inner and outer regions. The outer surface of this solid model is the complete outer surface digital model. It can be understood that the stitching operation involves tolerance calculations, and its success condition depends on the maximum gap value of the boundary edges. When the maximum gap between all boundaries to be stitched is less than a set tolerance threshold, the stitching operation is successful. The mathematical judgment condition for the stitching operation can be expressed as:

[0035] in: This represents the maximum gap distance between all pairs of boundary edges to be stitched. This represents the set of boundary edges to be stitched together. and Represents a set Any two boundary edges in the array (which may be the same or different). and These are the boundary edges and boundary edge any point on, Point With point The three-dimensional Euclidean distance between them.

[0036] In one embodiment of the present invention, see [reference] Figure 2The system calls upon a preset template standard size library and maximum transportable size constraints to determine the maximum allowable planar projected area and maximum allowable side length of a single template unit block. In the complete outer surface digital model, continuous regions with similar curvature characteristics are identified and marked as candidate parting regions. Based on the maximum allowable planar projected area and maximum allowable side length, the candidate parting regions are recursively divided until each sub-region satisfies the size constraints, with each sub-region corresponding to a template unit block. Simultaneously, the center normal vector of each template unit block is calculated, and the angle between the center normal vector and the preset demolding direction is checked, eliminating division schemes with angles exceeding a preset allowable angle threshold. With the optimization objectives of minimizing the total length of the dividing lines and the number of template unit block types, the optimal scheme is selected from all division schemes that satisfy the size and demolding direction constraints, and the dividing lines in the optimal scheme are defined as the preliminary parting lines. A three-dimensional cylindrical envelope model of each rebar in the internal rebar arrangement information is established. The minimum distance between the virtual dividing surface defined by the preliminary parting line and all three-dimensional cylindrical envelope models is calculated. When the minimum distance is less than a preset safe clearance threshold, it is determined that the preliminary parting line and the reinforcing steel have spatial interference. For the preliminary parting line segment that has spatial interference, a new feasible path is searched along the curved surface of the complete outer surface digital model within a preset adjustment distance range. The new feasible path must ensure that the minimum distance to the envelope model of all three-dimensional cylindrical reinforcing steel is greater than the safe clearance threshold, and does not violate the process constraints of the formwork unit segmentation. The original preliminary parting line segment that has spatial interference is replaced with the searched new feasible path, thereby completing the adjustment of all parting lines and forming the final parting line that does not conflict with the reinforcing steel.

[0037] In practice, the preset template standard size library and maximum transportable size constraints are called to determine the maximum allowable planar projection area and maximum allowable side length of a single template unit. The template standard size library contains common specifications of plywood and aluminum alloy templates that can be processed in the factory, such as lengths of 2400 mm, 2700 mm, and 3000 mm, and widths of 1200 mm and 1500 mm. The maximum transportable size constraints are determined by the construction road conditions and the lifting capacity of the tower crane on site. For example, the planar projection area of ​​a single template piece is limited to no more than 8 square meters, and the length of a single side is limited to no more than 3.5 meters.

[0038] In specific implementations, within the complete outer surface digital model, continuous regions with similar curvature characteristics are identified and marked as candidate segmentation regions. The identification of similar curvature characteristics involves calculating the normal vector and Gaussian curvature of each point on the model surface, clustering adjacent triangular facets with absolute curvature values ​​less than a set threshold and gentle normal changes into a single region. In some embodiments, the candidate segmentation regions are recursively segmented based on the maximum allowable planar projected area and the maximum allowable side length until each segmented sub-region satisfies the size constraints. Each sub-region corresponds to a template unit block. The recursive segmentation attempt employs a binary search or quadtree segmentation algorithm. Each segmentation calculates the bounding box size of the sub-region and compares it with the maximum allowable planar projected area and the maximum allowable side length.

[0039] During the segmentation process, the central normal vector of each template unit block is calculated. The angle between the central normal vector and the preset demolding direction is checked, and segmentation schemes with angles exceeding a preset allowable threshold are eliminated. The preset demolding direction is typically set vertically upwards or perpendicular to the main plane of the structure, with an allowable value of 15 degrees. That is, when the angle between the central normal vector and the demolding direction is greater than 15 degrees, it is considered that the template unit block may get stuck with the concrete during demolding, and this segmentation scheme is eliminated. The optimization objectives are to minimize the total length of the segmentation lines and the number of template unit block types. From all segmentation schemes that satisfy the dimensional and demolding direction constraints, the optimal scheme is selected. A shorter total length of segmentation lines helps reduce template seams, and a fewer number of template unit block types helps reduce the number of template specifications for easier factory processing and on-site management. The selection of the optimal scheme is achieved through a multi-objective optimization algorithm. In essence, the optimal scheme is selected from all segmentation schemes that satisfy the constraints, and the segmentation lines in the optimal scheme are defined as the initial parting lines.

[0040] A three-dimensional cylindrical envelope model of each rebar in the internal rebar arrangement information is established. The three-dimensional cylindrical envelope model of each rebar uses the rebar's centerline as its axis, and the nominal diameter of the rebar plus the allowable deviation of the protective layer is used as the cylinder diameter. The minimum distance between the virtual dividing surface defined by the preliminary parting line and all three-dimensional cylindrical envelope models is calculated. The minimum distance is calculated using a spatial geometric intersection algorithm. When the virtual dividing surface intersects with the three-dimensional cylindrical envelope model, the minimum distance is zero; when they do not intersect, the minimum distance is the shortest spatial distance from the virtual dividing surface to the surface of the three-dimensional cylindrical envelope model. In specific implementation, when the minimum distance is less than a preset safe clearance threshold, it is determined that the preliminary parting line and the rebar have spatial interference. The preset safe clearance threshold is set to 50 mm to ensure sufficient concrete protective layer thickness and operating space between the template edge and the rebar. Optionally, the safe clearance threshold can be adjusted according to specific engineering requirements and specifications.

[0041] For the initial parting line segment where spatial interference occurs, a new feasible path is searched within a preset adjustment distance range along the curved surface of the complete outer surface digital model. This new feasible path must ensure that the minimum distance to the envelope model of all three-dimensional cylindrical reinforcement is greater than the safe clearance threshold, and must not violate the process constraints of the template unit blocks. The adjustment distance range is set to 150 mm on each side of the original initial parting line segment. In some embodiments, a graph search algorithm is used to search for the new feasible path. The curved surface of the complete outer surface digital model is discretized into a grid, with grid nodes representing potential path points and grid edges representing potential path segments. The search target is a path from the starting point to the ending point, whose minimum distance to the envelope model of all three-dimensional cylindrical reinforcement is greater than 50 mm, and whose template unit blocks divided by the path still satisfy the size and demolding direction constraints. Process constraints include the maximum allowable side length and minimum interior angle of the template unit blocks. The original initial parting line segment where spatial interference occurs is replaced with the searched new feasible path, thereby completing the adjustment of all parting lines and forming the final parting line that does not conflict with the reinforcement. The adjustment process involves sequentially testing and optimizing each initial parting line segment until all parting line segments meet the avoidance requirements. Table 1 shows a comparison of key parameters before and after the parting line adjustment.

[0042] Table 1: Comparison of Key Parameters Before and After Parting Line Adjustment (Example Table)

[0043] In practice, the optimization process of searching for new feasible paths can be guided by a path scoring function. This function comprehensively considers path length, path smoothness, and the clear distance from the reinforcing bars. Its expression is:

[0044] in: Representing a path The overall score indicates that the lower the score, the better the path. Representing a path The total length; Representing a path The curvature variation penalty term is used to evaluate the smoothness of the path; the more severe the path curvature, the smoother the path. The larger the value; Representing a path Minimum distance between the three-dimensional cylindrical envelope model and all reinforced steel structures; , , These are the weighting coefficients for path length, curvature penalty, and minimum net distance, used to balance the priorities of different objectives. In template-based model splitting scenarios, they are typically set as follows: The weight is relatively large to ensure that avoiding the steel bars has the highest priority.

[0045] See Figure 3 In the interference optimization construction stage of 3D irregular formwork parting line based on BIM modeling technology, the comparison of key parameters between the preliminary and final parting lines intuitively reflects the engineering effect of interference avoidance adjustment. From a parameter perspective: Total parting line length: The preliminary parting line was 45.8m, and the final parting line increased to 48.7m. The slight increase in length is due to the curved surface avoidance adjustment of the interference section, a necessary sacrifice to ensure the clear spacing of the reinforcing bars. Number of formwork unit blocks: Both are 12, indicating that the avoidance optimization did not violate the original process constraints and size limitations of the formwork blocks, maintaining the standardization and manufacturability of formwork assembly. Minimum clear spacing with reinforcing bars: The preliminary parting line was only 5mm, resulting in serious spatial interference and failing to meet the requirements of concrete cover thickness and construction operation; the final parting line increased to 58mm, far exceeding the preset safe clear spacing threshold of 50mm, completely eliminating the interference risk between the formwork and the reinforcing bars. The maximum area of ​​the formwork blocks: the initial parting line was 7.2m², and the final parting line was 7.1m², with only minor fluctuations. This still meets the preset maximum transportation and processing size constraint of 8m², ensuring the feasibility of factory prefabrication and on-site hoisting of the formwork. Overall, this adjustment of the parting line, through surface path search and multi-objective optimization, maximized the maintenance of the dimensional constraints and process stability of the formwork blocks while strictly adhering to the priority of rebar avoidance. It achieved a balance between construction safety and processing economy, providing a reliable basis for the subsequent detailed design and on-site assembly of the three-dimensional irregular formwork.

[0046] In one embodiment of the present invention, the complete outer surface digital model is discretized into multiple independent curved surface pieces, with the final parting line as the boundary. Each curved surface piece corresponds to the casting contact surface of a template unit block. For each curved surface piece, its edge is used as a baseline and offset equidistantly in the normal direction to the outside of the concrete member to generate a template solid panel with a thickness equal to the template design thickness. At the edge of the template solid panel, three-dimensional features of back rib slots and connecting holes are automatically generated according to preset back rib arrangement rules. The template solid panel with back rib slots and connecting holes is combined with its corresponding original curved surface piece and assigned a unique template number, thus generating a template three-dimensional panel model. Three-dimensional models of connecting bolts and tie rods that match the back rib slots and connecting holes are obtained from a preset connector library. On the non-contact surface of the template three-dimensional panel model, three-dimensional models of stiffening ribs and vertical main ribs are automatically arranged according to the structural stress calculation results, ensuring that there is no geometric conflict between the stiffening ribs and the template solid panel and back rib slots. Calculate the required standard profile lengths and specifications for each connecting bolt, tie rod, stiffening rib, and vertical main rib, and generate the corresponding material list. Add 3D alignment and numbering markers for on-site assembly to the edges of the 3D template panel model. Assemble all the 3D template panel models under the same concrete component into a unified 3D irregular template assembly model according to their spatial relationships.

[0047] In practice, the complete outer surface digital model is discretized into multiple independent surface patches using the final parting line as the boundary. Each surface patch corresponds to the casting contact surface of a template unit block. The discretization operation is based on geometric Boolean cutting, cutting the complete outer surface digital model along the spatial surface defined by the final parting line. For each surface patch, its edge is used as a baseline and offset equidistantly in the normal direction to the outside of the concrete member, generating a template solid panel with a thickness equal to the template design thickness of 18 mm. The offset distance is 18 mm, and the offset direction is perpendicular to the surface patch surface outward, thus generating a three-dimensional solid plate parallel to the surface patch and with a specified thickness.

[0048] At the edge of the template solid panel, three-dimensional features of the back rib slots and connecting holes are automatically generated according to preset back rib arrangement rules. In some embodiments, the back rib arrangement rules include: arranging a connecting hole at 600 mm intervals along the center line of each straight edge of the template solid panel; and opening U-shaped slots for inserting steel back ribs at both ends and the midpoint of each straight edge, with a slot depth of 10 mm and a width 2 mm greater than the cross-sectional width of the back rib. At the arc-shaped edge of the template solid panel, a connecting hole is arranged every 300 mm along the arc length. Optionally, the connecting hole is a through hole with a diameter of 20 mm. It can be understood that the generation of the back rib slots and connecting holes is achieved through parametric feature modeling, automatically calculating the positions and adding three-dimensional modeling features based on the edge geometry of the template solid panel and preset rules.

[0049] In practice, a template solid panel with back rib grooves and connecting holes is generated and combined with its corresponding original curved surface piece, assigning a unique template number to generate the template 3D panel model. The combination operation manages the template solid panel and the original curved surface piece as an assembly in the 3D modeling software. The template number is generated according to the component number plus a block serial number, for example, "WQ-1-P01". From a preset connector library, standard connecting bolts and tie rod 3D models are matched to the back rib grooves and connecting holes. The connector library contains 3D models of standard fasteners of different specifications such as M16 and M20. The matching rule is to automatically select connecting bolt and tie rod models with matching models and dimensions based on the diameter and depth of the connecting holes, and precisely align them with the holes.

[0050] On the non-contact surface of the template's 3D panel model, based on the structural stress calculation results, the 3D models of stiffening ribs and vertical main ribs are automatically arranged, ensuring no geometric conflict between the stiffening ribs and the template solid panel and back rib slots. In some embodiments, the structural stress calculation results are provided by the finite element analysis module. Input parameters such as concrete lateral pressure and pouring height are used to calculate the stress and deflection distribution of the template panel. Stiffening ribs are automatically arranged in areas of large deflection or stress concentration. The stiffening ribs are typically modeled as 50 mm wide and 5 mm thick flat steel strips, arranged perpendicular to the direction of maximum template deformation. The vertical main ribs use a 3D model of double-section steel square tubes, arranged behind the template solid panel, aligned with the tie rods. It can be understood that the geometric conflict check is achieved through an interference check algorithm between 3D models, ensuring that the stiffening ribs, vertical main ribs, template solid panel, and back rib slots do not spatially overlap.

[0051] Calculate the required standard profile length and specifications for each connecting bolt, tie rod, stiffening rib, and vertical main rib, and generate a corresponding material list. The calculation process is based on the geometric dimensions of the 3D model of the connecting bolt, tie rod, stiffening rib, and vertical main rib, matching the closest standard profile specifications. Add 3D alignment and numbering markers for on-site assembly to the edges of the template 3D panel model. Alignment markers are raised triangular or circular positioning point 3D models, and numbering markers are 3D numbers and letters generated by stretching or imprinting. Optionally, the size and font size of the markers are proportionally set according to the size of the template unit block to ensure clear legibility. Refer to Table 2, which shows the detailed structural information of a typical template unit block.

[0052] Table 2: Template Unit Block Deepening Construction Information Table

[0053] In practice, the layout and quantity of stiffening ribs are calculated based on structural stiffness requirements, and their density is related to the stress distribution and allowable deformation of the formwork panel. The spacing of the vertical main ribs... With concrete lateral pressure and the allowable tension of the tie rod Related to, satisfying the relation ,in This refers to the vertical spacing of the tie rods. This relationship ensures that the tension in the tie rods remains within their bearing capacity under the lateral pressure of the concrete. All the 3D panel models of the formwork under the same concrete member are assembled into a unified 3D irregular-shaped formwork assembly model according to their spatial relationships. The assembly operation is performed in 3D design software by moving and rotating each individual 3D panel model of the formwork, aligning the back grooves on their edges with the connecting holes, forming a complete assembly model that reflects the relative positional relationships between the various sections.

[0054] See Figure 4The results show the efficiency and quality of each stage. From the perspective of process time (bar chart): the construction simulation process takes the longest, up to 6 hours, which is the key bottleneck of the whole process; the template modeling and stress calculation process takes the second longest, both 4 hours; the model extraction, rebar interference detection, and material generation process takes the shortest, both 2 hours; the remaining processes (surface reconstruction, template segmentation, parting line optimization, and accessory assembly) take between 3 and 5 hours. Overall, the process shows the characteristic of "moderate time for the early modeling and segmentation stage, and significantly increased time for the later simulation and calculation stage". From the perspective of process completion rate (line graph): the early modeling and segmentation stages, such as model extraction, surface reconstruction, and template segmentation, have the highest completion rates, maintaining in the 95%-100% range, reflecting the maturity and stability of BIM geometric modeling and segmentation logic. As the process progresses to stages such as rebar interference detection, parting line optimization, and template modeling, the completion rate gradually decreases to 85%-90%, reflecting the technical complexity and implementation difficulty of stages such as rebar and parting line interference adjustment and template 3D modeling. The completion rates of later stages such as stress calculation, construction simulation, and material preparation generation continue to decline, with the material preparation generation stage having the lowest completion rate (approximately 65%). This indicates that there is still considerable room for optimization in the digital processing and material preparation list generation stages, echoing the high time consumption of the construction simulation stage, revealing the core pattern that "the higher the complexity of later stages, the longer the time consumption and the lower the completion rate." In summary, the figure clearly reveals that the time consumption and completion rate of the three-dimensional irregular template construction design process are significantly negatively correlated: the early geometric modeling and block segmentation stages are efficient and of stable quality, while the later construction simulation, stress calculation and material generation stages are the weak points of the process, and the overall efficiency and quality need to be improved through algorithm optimization and standardization.

[0055] In one embodiment of the present invention, in a three-dimensional simulation environment, the three-dimensional panel model of each template and its associated connecting bolts, tie rods, stiffening ribs, and vertical main ribs are sequentially invoked. Following a preset standard construction procedure, the movement path, rotation action, and assembly sequence of the model components are defined. The standard construction procedure includes template transportation, on-site hoisting, temporary fixing, positioning, final connection, and overall verification. All related models are driven to move according to the defined sequence and path, simulating the entire process of on-site assembly of the three-dimensional irregular template. During the simulation, spatial collisions between moving models and between moving models and fixed permanent structural models are detected in real time, and the location and time of collisions are recorded. Based on the simulation and collision detection results, a construction simulation result containing animations of the standard assembly procedure and a potential risk warning report is generated. The construction simulation result is analyzed to statistically analyze the frequency and quantity of similar types and specifications of three-dimensional panel models of templates, connecting bolts, tie rods, stiffening ribs, and vertical main ribs. The material list is integrated, merging material requirements of the same specifications to generate a total material procurement list and a categorized material list. Based on the geometric dimensions and surface curvature of the template's 3D panel model, cutting path codes suitable for CNC cutting equipment are automatically generated. Based on the 3D models of the stiffening ribs and vertical main ribs, their machining details and opening positioning diagrams are automatically generated. The overall material purchase list, categorized blanking list, cutting path codes, machining details, and opening positioning diagrams are packaged and output as a digital machining file package for factory prefabrication.

[0056] In practical implementation, within the 3D simulation environment, the 3D panel model of each template and its associated connecting bolts, tie rods, stiffening ribs, and vertical main ribs are sequentially invoked. The 3D simulation environment is built based on a game engine or professional construction simulation software, capable of loading 3D models and assigning them physical and kinematic properties. Following preset standard construction procedures, the movement paths, rotation actions, and assembly sequences of the model components are defined. These preset standard construction procedures include template transportation, on-site hoisting, temporary fixing, positioning, final connection, and overall verification. The movement paths of the model components are set based on the on-site construction site layout, the tower crane's slewing radius, and the actual route from the template stacking area to the installation area. The rotation actions are defined based on the posture changes of the 3D panel model of the template during hoisting. The assembly sequence is determined based on the numbering and spatial relative positional relationship of the template unit blocks.

[0057] The system drives all relevant models to move according to a defined order and path, simulating the entire process of assembling a 3D irregular template on-site. During the simulation, it detects in real time whether spatial collisions occur between moving models and between moving models and fixed permanent structural models. Real-time spatial collision detection is achieved by combining a bounding box collision detection algorithm and a precise geometric interference check algorithm. Bounding box collision detection is used to quickly filter model pairs that may collide, while precise geometric interference check performs accurate distance calculations at the triangular facet level on the filtered model pairs. When the distance is less than a set threshold, it is determined to be a collision, and the location and time of the collision are recorded. In some embodiments, collision information is recorded as a log file containing the collision model number, the 3D coordinates of the collision location, the collision timestamp, and the collision depth.

[0058] In practice, based on simulation and collision detection results, a construction simulation outcome is generated, including animations of standard assembly procedures and potential risk warning reports. The standard assembly procedure animations are output as video files, showcasing the entire process from the hoisting of the first formwork panel to the installation of the last. The potential risk warning reports are generated as structured documents, listing all detected collision events, including which step in the standard construction procedure the collision occurred at, which formwork panels or components were involved, and the severity level of the collision. The construction simulation outcome is analyzed to statistically analyze the frequency and quantity of 3D panel models of the same type and specifications of formwork panels, connecting bolts, tie rods, stiffening ribs, and vertical main ribs. This statistical process is completed by traversing the unique identifiers and specification attribute information of the components recorded in the construction simulation outcome, utilizing database query and aggregation functions.

[0059] The material cutting list is integrated, merging material requirements of the same specifications to generate a master material procurement list and categorized cutting lists. In some embodiments, the integration operation is based on information such as the component's material code, specifications, length, and material, categorizing and summarizing all items in the material cutting list. The master material procurement list lists the total quantity and total length of various raw materials, standard parts, and connectors that need to be procured from the market, while the categorized cutting lists are organized by processing steps or workshop areas, listing the specific dimensions and quantities of various types of profiles that need to be cut, drilled, or shaped. Optionally, categorized cutting lists can be generated separately for component categories such as template panels, stiffening ribs, and main ribs.

[0060] Based on the geometric dimensions and surface curvature of the template's 3D panel model, cutting path codes suitable for CNC cutting equipment are automatically generated. This generation involves extracting the unfolded planar contour lines from the template's 3D model, discretizing these contour lines into straight line and circular interpolation commands according to the CNC cutting equipment's instruction set, and adding process parameters such as cutting speed, cutting power, and perforation points. It's understandable that for curved template 3D panel models, the unfolding process may involve the application of surface unfolding algorithms to approximate the 3D curved surface into a 2D flat sheet. Based on the 3D models of the stiffening ribs and vertical main ribs, detailed machining drawings and opening location diagrams are automatically generated. The detailed machining drawings include plan, elevation, and section views of the stiffening ribs and vertical main ribs, and annotate all dimensions, opening locations, and diameters. The opening location diagrams specifically annotate the locations and tolerance requirements of connecting holes and bolt holes. These drawings are generated through the automatic projection and annotation function of the 3D model. In practical implementation, the optimization problem of the annotation layout involved in automatically generating detailed machining drawings can be expressed as an objective function that minimizes the intersection of annotation lines, as shown below:

[0061] in: This indicates the cross-interference score of the layout annotations on the drawing; the lower the score, the better the layout. This indicates the total number of dimension lines in the drawing; Indicates the number of all leader lines in the drawing; It is an indicator function, when the first The dimension line and the first When a leader line intersects on the plane of a two-dimensional drawing, its value is 1; otherwise, it is 0. It is the first The dimension line and the first The algorithm assigns a weight factor to the intersection of leader lines. This weight factor can be set based on the importance of the geometric features indicated by the leader lines; for example, the intersection weight of leader lines representing major contour dimensions can be set higher. Understandably, the automated drawing algorithm will attempt to adjust the placement of the leader lines to minimize [the impact of the intersection]. This value generates clear, easy-to-read processing details.

[0062] The master material procurement list, categorized cutting list, cutting path code, machining details and hole positioning diagram are packaged and output as a digital machining file package for factory prefabrication. The packaging operation organizes these files according to a predefined folder structure and compresses them into a single file package. The file package can be sent directly to the CNC machining center in the factory through the construction management platform or mobile storage device.

[0063] See Figure 5In the digital machining process of irregular curved surface templates, the generation of CNC cutting paths and the accuracy of template planar unfolding directly determine the pre-fabrication quality in the factory. The solid black line in the figure represents the outer contour of the template, signifying the two-dimensional boundary contour of the three-dimensional surface after being mapped by the planar unfolding algorithm. This contour is obtained by equidistant offset and smoothing of the surface patch boundary of the template's three-dimensional panel model, ensuring that the geometric error with the original three-dimensional surface meets the CNC machining tolerance requirements. The dashed red line represents the CNC cutting path, which is the tool movement trajectory generated after offsetting and avoiding the outer contour. Its offset distance is equal to the sum of the cutting tool radius and the process allowance, avoiding overcutting or undercutting. As can be seen from the curve shape, the cutting path maintains a high degree of topological consistency with the outer contour. In areas with drastic curvature changes (such as the peak and valley segments near the unfolded width of 4mm), smaller step sizes are used to ensure the machining accuracy of complex surface features; in areas with gentle curvature (such as the unfolded width segment of 6–8mm), the step size is appropriately increased to improve cutting efficiency. The path data will be compiled into a G-code instruction set, which includes linear interpolation, circular interpolation, and speed control parameters, directly driving the CNC cutting equipment to complete the blanking of the template panel, providing a reference surface for the subsequent precision machining of the back rib groove and connecting hole.

[0064] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A three-dimensional irregular formwork construction design method based on BIM modeling technology, characterized in that, include: Obtain the full-discipline detailed design model of the component to be constructed, and extract the three-dimensional geometric boundary information and internal reinforcement arrangement information of the target irregular concrete component from the full-discipline detailed design model; Based on the three-dimensional geometric boundary information, the complete outer surface digital model of the target irregular concrete component is reconstructed in reverse, and the internal steel reinforcement arrangement information is associated with the complete outer surface digital model in the form of a spatial wireframe. The construction process of the complete outer surface digital model is analyzed. Based on the preset template assembly rules and demolding feasibility, multiple template unit blocks are automatically divided on the complete outer surface digital model, and preliminary parting lines that record the boundary information of each template unit block are generated. The internal steel reinforcement arrangement information is mapped to the digital model of the complete outer surface after the initial parting, the spatial interference between the steel reinforcement and the initial parting line is detected, and the initial parting line that causes spatial interference is automatically avoided and adjusted to form the optimized final parting line. Based on the final parting line, the complete outer surface digital model is segmented to generate a template three-dimensional panel model corresponding to each template unit block, and the spatial positioning coordinates of each template three-dimensional panel model are automatically calculated according to the three-dimensional geometric boundary information.

2. The three-dimensional irregular formwork construction design method based on BIM modeling technology according to claim 1, characterized in that, Based on the aforementioned three-dimensional geometric boundary information, the complete digital model of the outer surface of the target irregular concrete component is reconstructed in reverse, including: Read the point cloud data set, geometric cross-sectional contour line set, and surface control parameter set contained in the three-dimensional geometric boundary information; Using the point cloud data set and the geometric cross-sectional contour line set, a preliminary surface model of the target irregular concrete component is reconstructed through a non-uniform rational B-spline surface fitting algorithm. The smoothness and continuity of the preliminary surface model are optimized and verified based on the set of surface control parameters to ensure that the surface transition is smooth and there is no self-intersection. Extract all boundary edges of the preliminary surface model, and enclose the preliminary surface model into a solid model through boundary edge extension and stitching operations. The outer surface of the solid model is the complete outer surface digital model.

3. The three-dimensional irregular formwork construction design method based on BIM modeling technology according to claim 2, characterized in that, Construction process analysis is performed on the complete external surface digital model. Based on preset template assembly rules and demolding feasibility, multiple template unit blocks are automatically divided on the complete external surface digital model, including: The preset template standard size library and maximum transportable size constraints are used to determine the maximum allowable planar projected area and maximum allowable side length of a single template unit block; In the complete digital model of the outer surface, continuous regions with similar curvature characteristics are identified, and these continuous regions are marked as candidate segmentation regions; Based on the maximum allowable planar projected area and the maximum allowable side length, the candidate segmentation region is recursively segmented until each segmented sub-region satisfies the size constraints, and each sub-region corresponds to a template unit block; While segmenting, the center normal vector of each template unit block is calculated, the angle between the center normal vector and the preset demolding direction is checked, and segmentation schemes with angles exceeding the preset allowable angle threshold are eliminated. With the optimization objectives of minimizing the total length of the dividing line and the number of template unit block types, the optimal scheme is selected from all the dividing schemes that satisfy the size and demolding direction constraints, and the dividing line in the optimal scheme is defined as the preliminary parting line.

4. The three-dimensional irregular formwork construction design method based on BIM modeling technology according to claim 3, characterized in that, The automatic avoidance adjustment of the preliminary parting line that causes spatial interference to form the optimized final parting line includes: Establish a three-dimensional cylindrical envelope model for each steel bar in the internal steel bar arrangement information; Calculate the minimum distance between the virtual segmentation surface defined by the initial parting line and all the three-dimensional cylindrical envelope models; When the minimum distance is less than the preset safe clearance threshold, it is determined that the preliminary parting line and the reinforcing bar are spatially interfering. For the initial parting line segment where spatial interference occurs, a new feasible path is searched along the curved surface of the complete outer surface digital model within a preset adjustment distance range. The new feasible path must ensure that the minimum distance to the envelope model of all steel reinforcement three-dimensional cylinders is greater than the safe net distance threshold, and does not violate the process constraints of the template unit segmentation. The original initial parting line segment that caused spatial interference is replaced by the new feasible path found, thereby completing the adjustment of all parting lines and forming the final parting line that does not conflict with the reinforcing bars.

5. The three-dimensional irregular formwork construction design method based on BIM modeling technology according to claim 4, characterized in that, Based on the final parting line, the complete outer surface digital model is segmented to generate a template 3D panel model corresponding to each template unit block, including: Using the final parting line as the boundary, the complete outer surface digital model is discretized into multiple independent surface pieces, each surface piece corresponding to the casting contact surface of a template unit block; For each of the curved surface patches, with its edge as the baseline, it is offset equidistantly in the normal direction to the outside of the concrete member to generate a template solid panel with a thickness equal to the template design thickness. At the edge of the template solid panel, three-dimensional features of the back rib groove and connection hole are automatically generated according to the preset back rib arrangement rules. The template solid panel with the back rib groove and connection hole is generated and combined with its corresponding original curved surface piece, and a unique template number is assigned to it, thus generating the template three-dimensional panel model. All the three-dimensional panel models of the templates under the same concrete component are assembled into a whole three-dimensional irregular template group model according to their spatial position relationship.

6. The three-dimensional irregular formwork construction design method based on BIM modeling technology according to claim 5, characterized in that, It also includes steps for refining the construction of each template's 3D panel model: From the preset connector library, obtain three-dimensional models of connecting bolts and tie rods that match the back groove and connecting hole positions according to the standard. On the non-contact surface of the template 3D panel model, based on the structural stress calculation results, the 3D models of stiffening ribs and vertical main ribs are automatically laid out, and it is ensured that there is no geometric conflict between the stiffening ribs and the template solid panel and the back rib groove. Calculate the required standard profile length and specifications for each of the aforementioned connecting bolts, tie rods, stiffening ribs, and vertical main ribs, and generate the corresponding material list; Three-dimensional markers for on-site assembly are added to the edges of the template's three-dimensional panel model, including alignment and numbering marks.

7. The three-dimensional irregular formwork construction design method based on BIM modeling technology according to claim 6, characterized in that, It also includes the step of simulating the construction process based on the overall three-dimensional irregular template group model: In the 3D simulation environment, the 3D panel model of each template and its associated connecting bolts, tie rods, stiffening ribs and vertical main ribs are called in sequence; According to the preset standard construction procedures, the movement path, rotation action and assembly sequence of the model components are defined. The standard construction procedures include template transportation, on-site hoisting, temporary fixing, positioning, final connection and overall verification. Drive all relevant models to move in the defined order and path to simulate the entire process of assembling a three-dimensional irregular template on site; During the simulation, spatial collisions between motion models and between motion models and fixed permanent structure models are detected in real time, and the location and time of the collision are recorded. Based on the simulation and collision detection results, a construction simulation result containing animations of standard assembly procedures and potential risk warning reports is generated.

8. The three-dimensional irregular formwork construction design method based on BIM modeling technology according to claim 7, characterized in that, It also includes steps for optimizing material cutting and processing based on construction simulation results: The construction simulation results were analyzed, and the frequency and number of occurrences of the same type and specifications of the template 3D panel model, connecting bolts, tie rods, stiffening ribs and vertical main ribs were statistically analyzed. Integrate the aforementioned material cutting lists, merge the material requirements of the same specifications, and generate a total material procurement list and a categorized material cutting list; Based on the geometric dimensions and surface curvature of the template 3D panel model, a cutting path code suitable for CNC cutting equipment is automatically generated; Based on the three-dimensional model of the stiffening rib and the vertical main rib, the machining details and hole positioning diagram are automatically generated. The total material procurement list, categorized cutting list, cutting path code, processing details and hole positioning diagram are packaged and output as a digital processing file package for factory prefabrication.

9. The three-dimensional irregular formwork construction design method based on BIM modeling technology according to claim 1, characterized in that, The process of obtaining the full-discipline detailed design model of the component to be constructed includes: Obtain design models from multiple disciplines, including architecture, structure, and mechanical and electrical engineering, that contain the target irregularly shaped concrete component; Perform geometric consistency checks and conflict detections on the design models of the architecture, structure, and mechanical and electrical engineering disciplines. Based on the detection results, coordinate system alignment, geometric position alignment, and missing information repair were performed on the design models of the multiple disciplines. From the design models of multiple disciplines that have completed coordinate system one, geometric position alignment and missing information repair, extract and integrate the geometric information of structural components, the layout information of steel bars, the positioning information of embedded parts and the spatial constraint information of adjacent components. Generate a single data model containing the geometric information of the structural components, the arrangement information of the reinforcing bars, the positioning information of the embedded parts, and the spatial constraint information of the adjacent components. The single data model is the full-discipline detailed design model. In the comprehensive professional detailed design model, the geometric boundaries, internal reinforcement, and relationships of the target irregular concrete component and its surrounding related components have all been expressed in three dimensions and associated with data.

10. The three-dimensional irregular formwork construction design method based on BIM modeling technology according to claim 2, characterized in that, Using the point cloud dataset and the geometric cross-sectional contour set, a preliminary surface model of the target irregular concrete component is reconstructed through a non-uniform rational B-spline surface fitting algorithm, including: The point cloud dataset is denoised and processed to obtain a feature point cloud dataset; The geometric cross-sectional contour line set is smoothed and repaired to obtain continuous closed cross-sectional contour lines; Using the feature point cloud set as the surface shape control points and the continuous closed cross-sectional contour line as the cross-sectional guide line, a control mesh for a non-uniform rational B-spline surface fitting algorithm is constructed. Based on the control mesh, the surface generation calculation module of the non-uniform rational B-spline surface fitting algorithm iteratively calculates the preliminary surface control point matrix and node vector sequence that satisfy the spatial position constraints of the feature point cloud set and the orientation constraints of the continuous closed cross-sectional contour line. Based on the preliminary surface control point matrix, node vector sequence, and preset surface order, a mathematical expression for a non-uniform rational B-spline surface is generated. Based on the mathematical expression of the non-uniform rational B-spline surface, a continuous and differentiable surface model is reconstructed in the three-dimensional modeling space. The surface model is the preliminary surface model of the target irregular concrete component.

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