Rapid modeling system for digital pattern making of sofa soft bed

Abstract

The invention relates to the field of furniture manufacturing, in particular to a rapid modeling system for digital pattern making of a sofa soft bed. The system comprises a modeling platform module, a three-dimensional modeling and two-dimensional expansion module, a component library and material database, a structure disassembly and consumable statistics module and a process output module. Parametric modeling is carried out on parts such as a seat bag, a backrest, armrests and a bottom frame, a three-dimensional structure is automatically generated, a complex curved surface is unfolded through an energy optimization algorithm, and leather cloth version data are output in combination with splicing optimization. Calling the standard component library by the system, matching material parameters, calculating the consumption of consumables and a loss coefficient, and generating a consumable list; and forming a structure decomposition graph based on the assembly relationship, automatically adding a process label, and finally outputting a digital process document which can be directly used for production. According to the invention, full automation of the plate making process is realized, the development period is shortened, the cost is reduced, and the consistency and production efficiency are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of furniture manufacturing, in particular to a rapid modeling system for digital pattern making of sofa bed. BACKGROUND

[0002] With the development of sofa and bed products towards rapid iteration and batch production, the digitalization and automation of the pattern making link have become the key to improving design accuracy and shortening development cycle. Researching an efficient digital pattern making system is of great significance for reducing manual dependence, reducing material waste and promoting the transformation and upgrading of the furniture manufacturing industry.

[0003] Although various three-dimensional modeling tools have been introduced in existing sofa bed pattern making, there are still some deficiencies. The unfolding of curved surface components such as seat, backrest and armrest relies on manual adjustment, which is prone to errors and prolongs the development cycle. The component library and material data lack unified management, which cannot realize automatic matching, and the manual statistics of material list has high error rate and serious waste. The process annotation relies on experience and is time-consuming and laborious, and it is difficult to maintain consistency. The above deficiencies make it difficult for traditional pattern making to meet the needs of sofa bed production for rapid modeling, accurate material control and unified process output. SUMMARY

[0004] The present application provides a rapid modeling system for digital pattern making of sofa bed, which aims to realize the direct connection between design input and production process by constructing a digital rapid modeling and automatic pattern making system, and effectively improve the development speed and consistency.

[0005] To achieve the above purpose, the present application provides the following technical solutions:

[0006] A rapid modeling system for digital pattern making of sofa bed, comprising:

[0007] A modeling platform module based on a three-dimensional parametric modeling platform, which receives images or design inputs of sofa bed products and defines parameters of seat, backrest, armrest, bottom frame, support structure and connecting components;

[0008] A three-dimensional modeling and two-dimensional unfolding module, which generates a three-dimensional structure model according to the parameterized definition, and unfolds complex curved surfaces based on a curved surface flattening algorithm, and generates two-dimensional leather pattern data conforming to the cutting process by combining with a splicing optimization strategy;

[0009] A component library and material database for storing standardized component models and material specification information, and the system calls corresponding components and matches with material parameters during modeling;

[0010] A structure disassembly and consumable statistics module generates a structure disassembly diagram conforming to a production standard according to the three-dimensional structure model, dynamically matches optimal material specifications based on a material database, calculates consumable consumption and loss coefficients, and outputs a complete consumable list;

[0011] A process output module automatically annotates the two-dimensional cloth version and the structure disassembly diagram with processes to form a digital process document that can be directly used for production.

[0012] As a preferred technical solution of the present application, the parameterization definition includes:

[0013] Obtaining a component contour in an input image or design file, selecting a reference point on the contour and establishing a reference line;

[0014] Setting length and width size parameters, curved surface curvature parameters and connection position parameters of the component based on the reference point and the reference line;

[0015] Solidifying the parameters into a parameterized modeling file of the component for subsequent three-dimensional modeling calling.

[0016] As a preferred technical solution of the present application, the generation of the three-dimensional structure model includes the following steps:

[0017] Importing the component parameterized modeling file into a three-dimensional parameterized modeling platform, and generating a geometric body basic framework according to the size parameters of the component;

[0018] Calling the parameterized modeling file on the geometric body basic framework to form a complete component curved surface model;

[0019] Importing the component curved surface model into the three-dimensional parameterized modeling platform, automatically establishing a matching relationship according to interface features and assembly constraints, and combining in assembly order to form a three-dimensional structure model of the sofa bed.

[0020] As a preferred technical solution of the present application, the steps of the curved surface flattening algorithm for unfolding a complex curved surface include:

[0021] Delaunay triangular meshing is performed on the curved surface of the component to be unfolded to calculate the area deformation energy of each triangular element;

[0022] An optimization equation set is established with the total deformation energy minimization as an objective function;

[0023] A conjugate gradient method is used to solve two-dimensional plane coordinates of the grid nodes;

[0024] A two-dimensional contour line and an internal structure line are generated according to the unfolding result.

[0025] As a preferred technical solution of the present application, the splicing optimization strategy includes:

[0026] Boundary recognition is performed on all unfolded two-dimensional component contours, and adjacent component splicing matching is performed according to contour edge shapes; in the two-dimensional leather pattern splicing process, splicing priorities are established based on the curvature continuity of component boundaries, material texture directions and process stress constraints, and an optimal splicing path is determined through a global optimization algorithm.

[0027] As a preferred technical solution of the present application, the step of calling corresponding components and matching with material parameters comprises:

[0028] Geometric feature parameters and size constraint conditions of the components are extracted, and standardized component models that are matched are searched in a component library according to geometric similarity;

[0029] Candidate materials are screened in a material database according to material requirement specifications of the component models;

[0030] Weighted sorting is performed according to three fields of cost, thickness matching degree and tensile strength, and a material specification with the highest score is selected to be bound with the component model.

[0031] As a preferred technical solution of the present application, the step of generating a structure decomposition diagram comprises:

[0032] Connection constraints and position constraint relationships between components are extracted based on a three-dimensional structure model to form a constraint atlas;

[0033] Components are separated step by step according to a hierarchical order of the constraint atlas, and connection hole positions, mounting directions and assembly serial numbers are marked on surfaces of the separated components;

[0034] The separation result is projected to a two-dimensional plane together with the constraint relationships to generate a structure decomposition diagram containing component numbers, assembly sequences and connection relationships.

[0035] As a preferred technical solution of the present application, the step of calculating consumable usage and loss coefficients comprises:

[0036] Volume data and surface area data of the components are extracted from the three-dimensional structure model;

[0037] Density parameters, thickness specifications and standard plate sizes corresponding to the material types of the components are queried in a material database;

[0038] Based on the component volumes and material densities, entity material weights are calculated, and based on the surface areas and material thicknesses, plate area requirements are calculated;

[0039] According to the material types, corresponding processing loss coefficients are set, including cutting loss, corner loss and process loss;

[0040] The actual requirement amount is multiplied by the loss coefficient to obtain the total consumable amount, and the number is rounded and the specification is matched according to the material specifications.

[0041] As a preferred technical scheme of the present application, the automatic process marking step comprises:

[0042] Geometric analysis is performed on the contour boundary of the two-dimensional leather pattern, straight line segments, arc line segments and inflection point positions are identified, and dimension marking points are automatically inserted on the boundary at a preset interval;

[0043] According to the material properties and thickness parameters of the leather pattern, seam edge width values and sewing process symbols are marked at the seam boundary positions;

[0044] The components in the structural exploded view are classified according to material type, processing tolerance ranges are marked on wooden components, and welding symbols and surface treatment requirements are marked on metal components;

[0045] The assembly constraint relationships between components are extracted, and bolt specifications, hole diameter sizes and tightening torque values are marked at the connection positions;

[0046] The two-dimensional leather pattern and the structural exploded view after marking are generated into a unified format digital process document according to unified format requirements.

[0047] The present application has the following beneficial effects:

[0048] 1. The present application combines parameterized modeling, complex surface energy unfolding, intelligent nesting optimization, and component library and material database linkage to form a full-process digital system from modeling to process output. The system effectively replaces traditional manual sample making and manual disassembly processes, significantly shortens product development cycle, and reduces sample making cost.

[0049] 2. The present application realizes automatic processing in complex surface unfolding and nesting, combines with database-driven component and material matching mechanism and automatic process marking function, not only ensures the accuracy of the unfolding result and the high utilization rate of the nesting, but also realizes the consistency and standardization of the process file, significantly improves the consistency and production efficiency of product development. BRIEF DESCRIPTION OF DRAWINGS

[0050] The accompanying drawings are used to provide a further understanding of the present application, and constitute a part of the specification, together with the embodiments of the present application, to explain the present application, and do not constitute a limitation of the present application. In the drawings:

[0051] Figure 1 is a structural schematic diagram of a rapid modeling system for sofa bed digital sample making according to the present application;

[0052] Figure 2 is a flowchart of a rapid modeling system for sofa bed digital sample making according to the present application. DETAILED DESCRIPTION

[0053] The preferred embodiments of the present application are described below in conjunction with the accompanying drawings, it should be understood that the preferred embodiments described herein are merely intended to illustrate and explain the present application, and are not intended to limit the present application.

[0054] Embodiment one: as shown, a rapid modeling system for sofa bed digital plate making, comprising: Figure 1

[0055] Modeling platform module, based on three-dimensional parameterized modeling platform, receiving sofa bed product image or design input, parameterized definition of seat bag, backrest, armrest, bottom frame, support structure, connecting parts;

[0056] Further, the parameterized definition includes:

[0057] Obtaining the component contour in the input image or design file, selecting the reference point on the contour and establishing the reference line;

[0058] Setting the length and width size parameters, curved surface curvature parameters and connection position parameters of the component based on the reference point and reference line;

[0059] Solidifying the parameters into the parameterized modeling file of the component for subsequent three-dimensional modeling call.

[0060] Specifically, in this embodiment, the modeling platform module uses SolidWorks as the underlying modeling engine, and realizes the parameterized modeling function through secondary development interface. After the system starts, it automatically loads the sofa bed special modeling template, which presets the basic geometric framework of six types of components including seat bag, backrest, armrest, bottom frame, support structure and connecting parts.

[0061] When the user uploads the sofa product image, the system first calls the image recognition algorithm to extract the component contour. For design file input, the system directly parses the geometric information in the CAD format file. After the contour extraction is completed, the system automatically identifies the feature points on each component contour as reference points, and the feature point selection rules are: setting the reference points at the geometric center, maximum curvature change point and symmetry axis intersection point of the contour. The reference line is formed by connecting adjacent reference points, forming the main geometric control line of the component.

[0062] ​In the parameterization definition process, the system calculates the length and width parameters of the component according to the coordinates of the reference points. The length parameter L is defined as the maximum projection distance of the component profile in the direction of the main reference line, and the width parameter W is defined as the maximum projection distance perpendicular to the direction of the main reference line. The curvature parameter of the curved surface is calculated by the three-point circular arc fitting method. Any three adjacent feature points on the profile are selected, and the curvature radius R is obtained by circular arc fitting, and the curvature value K = 1 / R. The connection position parameter is determined by identifying the adjacency relationship between components. The system automatically detects the overlapping area of the adjacent component profiles, and takes the geometric center of the overlapping area as the connection reference point. The connection direction is determined by the direction of the line connecting the geometric centers of the two components.

[0063] All extracted parameters are stored in XML format as parameterized modeling files. The file structure includes four main fields: component type identification, geometric parameter array, material attribute identification, and assembly constraint relationship. The system generates a unique parameterized ID for each component to ensure the accuracy of parameter calling in the subsequent modeling process. After the parameter file is generated, it is automatically saved to the project database for calling by the three-dimensional modeling and two-dimensional development modules.

[0064] The three-dimensional modeling and two-dimensional development module generates a three-dimensional structure model based on the parameterization definition, and develops complex curved surfaces based on the curved surface flattening algorithm. Combined with the splicing optimization strategy, it generates two-dimensional leather pattern data that meets the cutting process;

[0065] Further, the generation of the three-dimensional structure model includes the following steps:

[0066] Import the component parameterized modeling file into the three-dimensional parameterized modeling platform, and generate a geometric body basic framework according to the size parameters of the component;

[0067] Call the parameterized modeling file on the geometric body basic framework to form a complete component curved surface model;

[0068] Import the component curved surface model into the three-dimensional parameterized modeling platform, automatically establish the matching relationship according to the interface features and assembly constraints, and combine them in the assembly order to form a three-dimensional structure model of the sofa bed.

[0069] Specifically, the established parametric modeling file is imported into the three-dimensional parametric modeling platform, and the system directly generates the corresponding geometric body basic framework according to the geometric constraint information contained in the file. The geometric body is based on voxel units and spatial coordinates, and the accuracy of the position of each boundary is maintained through the constraint condition, thereby ensuring that the framework size is consistent with the input design. In the geometric body basic framework, the control point set of the curved surface is further loaded, and the modeling platform interpolates the continuous curved surface according to the spatial distribution of the control points, and adjusts the curvature value of the curved surface to make it consistent with the design form of the part. Then the assembly interface data in the file is loaded, and the geometric features of the assembly hole, slot or positioning block are established on the framework to form a complete part curved surface model. The part curved surface models are combined in the modeling platform according to the assembly sequence set in the parametric modeling file. The system identifies the interface features of adjacent parts, aligns the mutually cooperating boundaries and establishes assembly constraint relationships, such as plane alignment, hole axis coincidence or positioning block insertion, thereby realizing the precise cooperation between parts. With the gradual assembly of all parts, a complete sofa bed three-dimensional structure model is finally obtained, which accurately reflects the geometric form and assembly relationship of the actual product, and provides basic data for subsequent development and process design.

[0070] Further, the step of the curved surface flattening algorithm for unfolding the complex curved surface comprises:

[0071] Delaunay triangular meshing is performed on the curved surface of the part to be unfolded, and the area deformation energy of each triangular element is calculated;

[0072] An optimization equation set is established with the total deformation energy as the objective function;

[0073] The conjugate gradient method is used to solve the two-dimensional plane coordinates of the grid nodes;

[0074] A two-dimensional contour line and an internal structure line are generated according to the unfolding result.

[0075] Specifically, the curved surface flattening algorithm uses a mesh unfolding method based on energy minimization to realize the two-dimensional unfolding of the complex curved surface. The system uses Delaunay triangular meshing technology to automatically generate triangular mesh elements covering the entire curved surface of the part to be unfolded. During the meshing process, the system adaptively adjusts the grid density according to the geometric characteristics of the curved surface, increases the grid density in areas with sharp curvature changes to ensure the accuracy of the unfolding, and appropriately reduces the grid density in flat areas to improve the calculation efficiency.

[0076] The area deformation energy of each triangular element is calculated by comparing the original area in three-dimensional space with the target area after two-dimensional unfolding. Let the area of the triangular element in three-dimensional space be S 3D , and the area after two-dimensional plane unfolding be S 2D , then the area deformation energy E of the element is defined as E = (S 2D - S 3D ) / S 3D . 3D , and the area after two-dimensional plane unfolding be S 2D , then the area deformation energy E of the element is defined as E = (S 2D - S 3D ) / S 3D .2D - S 3D ) 2 / S 3D 2 The system traverses all the grid cells, accumulates the area deformation energy of each cell to obtain the total deformation energy function.

[0077] The optimization equation set is established with the total deformation energy as the objective function. The system takes the two-dimensional plane coordinates of each node in the grid as the optimization variables, and establishes the constraint conditions including the boundary node fixed constraint and the adjacent node distance maintaining constraint. The boundary node fixed constraint is realized by selecting feature points on the surface boundary as fixed reference points, which ensures that the surface does not have overall displacement or rotation during the unfolding process. The adjacent node distance maintaining constraint requires that the distance between adjacent grid nodes after unfolding is as close as possible to the distance in the original three-dimensional space, in order to reduce the unfolding deformation.

[0078] In the conjugate gradient method solving process, the system sets the initial solution as the orthogonal projection coordinates of the surface on the main plane. The algorithm determines the descent direction by iteratively calculating the gradient vector of the objective function, and determines the optimal step size using the linear search method. After each iteration, the system checks the convergence condition, and when the difference between the objective function values of two consecutive iterations is less than the set threshold, the algorithm is considered to have converged and the optimal solution is output.

[0079] In the unfolding result processing stage, the system reconstructs the geometric shape of the unfolded surface according to the two-dimensional coordinates of the grid nodes obtained by optimization. The two-dimensional contour line is generated by connecting the boundary grid nodes, and the contour line is fitted with B-spline curve to obtain a smooth boundary. The internal structure line includes the corresponding line on the unfolded plane of the feature line on the original surface, such as the decorative seam line, the blocking line and the positioning line, etc. The system reconstructs the two-dimensional geometric shape of the feature line by tracking the position change of the grid nodes on the feature line after unfolding, and smoothes the line to eliminate the jagged effect caused by grid division.

[0080] To ensure the unfolding quality, the system automatically detects the area deformation rate and angle deformation rate of the unfolding area after the unfolding is completed. When the deformation rate of a certain area exceeds the preset threshold of 5%, the system automatically adds a division line in that area to divide the large deformation area into multiple small deformation areas for separate unfolding, ensuring that the geometric accuracy of the final two-dimensional leather pattern meets the cutting process requirements.

[0081] Further, the splicing optimization strategy comprises:

[0082] Boundary recognition is performed on all the unfolded two-dimensional component contours, and splicing matching of adjacent components is performed according to the contour edge shape. In the two-dimensional leather pattern splicing process, the splicing priority is established based on the curvature continuity of the component boundary, the material texture direction and the process stress constraint, and the optimal splicing path is determined by a global optimization algorithm.

[0083] Specifically, in the splicing matching stage, the system comprehensively considers three factors of boundary curvature continuity, material texture direction and process stress constraint to establish a splicing priority model. Specifically:

[0084] Curvature continuity score calculation: the system equally divides each boundary into ten sampling segments, calculates the local curvature value at each sampling point using the three-point arc fitting method, and calculates the average value of the curvature difference of all sampling points as the curvature deviation basic data by comparing the curvature difference of the corresponding sampling points of the two boundaries.

[0085] Texture direction score calculation: the system extracts the texture direction vector of the material of the component from the material database, takes the warp direction as the main vector for fabric materials, and takes the natural texture direction as the main vector for leather materials, and calculates the included angle between the texture direction vectors of the two components to be spliced.

[0086] Stress constraint score calculation: based on the statics analysis results of the three-dimensional structure model, the system extracts the stress distribution data of each component boundary, compares the maximum stress value of the boundary with the allowable stress of the material, and calculates the stress safety factor value.

[0087] Score mapping conversion: the system converts the curvature deviation, texture angle and stress safety factor into standardized scores of zero to one hundred through a preset mapping function. The smaller the curvature deviation, the smaller the texture angle and the higher the safety factor, the higher the corresponding score, and the three types of mapping functions are realized by using piecewise linear interpolation method.

[0088] The system weights the three scores according to weights W1, W2 and W3 to form the splicing priority score:

[0089] S=W1·f(ΔK)+W2·f(θ)+W3·f(σ);

[0090] Where f(ΔK), f(θ), f(σ) represent curvature difference function, texture angle function and stress constraint function respectively, and weights W1, W2 and W3 can be set according to actual application, which is not limited in the embodiment.

[0091] In the global optimization stage, the system constructs the objective function:

[0092] F=α·U+β·∑S-γ·L;

[0093] Where: U represents material utilization (needs to be maximized); ∑S represents the total priority of all splicing boundaries; L represents the total length of the splicing path (needs to be minimized), and α, β, L are the weight coefficients of the corresponding contents, and the initial values can be set to 0.5, 0.3 and 0.2 respectively.

[0094] It should be noted that W1, W2 and W3 and α, β, L above

[0095] The objective function is iteratively optimized by a hybrid solving strategy of genetic algorithm + local hill climbing search: genetic algorithm is used to generate initial candidate solutions of global splicing path; in each generation evolution, individuals with high material utilization rate and high priority score are selected into the next generation; local hill climbing search is performed on the candidate solutions to correct path details (such as fine-tuning angles, boundary alignment methods); when the improvement rate of the objective function in the last two generations is less than 1%, the algorithm is considered to be converged, and the optimal splicing path is output.

[0096] The final generated splicing path not only ensures the continuity of the boundary geometry, but also takes into account the fabric direction and process stress constraints, so as to obtain the scheme with the highest material utilization rate and the optimal splicing stability.

[0097] Component library and material database are used to store standardized component models and material specification information, and the system calls corresponding components and matches with material parameters during modeling;

[0098] Further, the step of calling corresponding components and matching with material parameters comprises:

[0099] Extracting the geometric feature parameters and size constraints of the component, and searching for a matched standardized component model in the component library according to geometric similarity;

[0100] According to the material requirement specification of the component model, candidate materials are screened in the material database;

[0101] According to the cost, thickness matching degree and tensile strength, the three fields are weighted and sorted, and the material specification with the highest score is selected to bind with the component model.

[0102] Specifically, the system calls the component library and material database during modeling to complete the matching of standardized component models and material specifications. The component library adopts a hierarchical index structure for management, and six categories of standardized models are preset, including seat, backrest, handrail, bottom frame, support and connecting piece. Each category of model is attached with geometric feature parameters and adaptation range. The material database adopts tabular storage method, including material category, thickness specification, density parameter, plate size and mechanical performance index.

[0103] During the calling process, the system first extracts the geometric feature parameters of the component from the three-dimensional modeling result, including length, width, height, surface area, volume and key interface position size, and uses these parameters to calculate the geometric similarity with the index data in the component library. The similarity calculation adopts the normalized Euclidean distance method, which compares the parameter vectors of the input component and the candidate component model item by item to obtain the similarity score. The system selects the standardized component model with the highest similarity and within the set threshold range as the matching result.

[0104] After determining the standard component model, the system extracts the material properties required by the model, such as density interval, thickness range, and mechanical performance requirements, and screens in the material database. The screening step takes the material category as the primary condition, such as searching for wood components in the wood category and searching for metal connectors in the steel or aluminum category. Then, according to the geometric feature requirements and performance parameters, a candidate material set is formed.

[0105] After the candidate set is formed, the system sorts the materials, with the sorting indicators including cost, thickness matching degree, and tensile strength. Cost is used as an economic evaluation indicator, thickness matching degree is calculated by the difference between the required thickness of the component and the material thickness specification, and the smaller the difference, the higher the score, and tensile strength is used to evaluate the carrying capacity of the material. The system sets the weights, with the cost weight being 0.5, the thickness matching degree weight being 0.2, and the tensile strength weight being 0.3, and calculates the weighted total score for each candidate material. The sorting result takes the material specification with the highest total score as the final binding object, and writes the specification parameters into the component model file, forming a "standard component - optimal material" binding relationship. It should be noted that the weights of cost, thickness, and tensile strength can be adjusted according to actual conditions, and are not limited in this embodiment.

[0106] After matching is completed, the system stores the results in the project database to ensure direct calling in subsequent consumable statistics and process output links. This implementation method can ensure the accuracy and rationality of the called components and material specifications through component recognition driven by geometric similarity and material screening under performance constraints, and realizes consistency in the whole process from design input to process output.

[0107] The structure disassembly and consumable statistics module generates a structure decomposition diagram that meets the production standards based on the three-dimensional structure model, dynamically matches the optimal material specification based on the material database, calculates the consumable consumption and loss coefficient, and outputs a complete consumable list;

[0108] Further, the structure decomposition diagram generation step includes:

[0109] Based on the three-dimensional structure model, the connection constraints and position constraints between components are extracted to form a constraint graph;

[0110] According to the hierarchical order of the constraint graph, the components are separated level by level, and the connection hole position, mounting direction, and assembly sequence are marked on the surface of the separated components;

[0111] The separation result and the constraint relationship are projected onto a two-dimensional plane to generate a structure decomposition diagram containing component number, assembly sequence, and connection relationship.

[0112] Specifically, the generation of the structural exploded view is based on the assembly constraint relationships of the three-dimensional model. After completing the sofa bed three-dimensional structure model construction, the system first analyzes the model assembly relationship, extracts the connection constraints and position constraints between components. For example, the bottom frame and the support are bolted, the back and the seat bag are connected, and the armrest and the bottom frame are connected by mortise and tenon. The system abstracts these constraint information into a constraint graph, where the nodes represent components and the edges represent assembly constraints, forming a hierarchical dependency structure between components.

[0113] After the constraint graph is established, the system expands the components according to the hierarchical order of the graph. For the components in the outermost layer, the system separates them in space according to the constraint direction, for example, separates the back from the connection constraints of the seat bag and the bottom frame. Then, the system processes the next level of constraints one by one, gradually completing the hierarchical disassembly of the components. This step-by-step separation process ensures that the disassembly path is consistent with the actual assembly sequence, avoiding the problem of virtual drawings not matching the production process.

[0114] During the separation of components, the system generates a unique number for each component and automatically adds labeling information to the three-dimensional model surface. The labeling information includes connection hole position, installation direction arrow, and assembly sequence number. For example, the surface of the metal support is labeled with bolt hole diameter and hole position coordinates, and the surface of the wooden bottom frame is labeled with assembly direction arrow and number sequence. These labeling information is synchronized in the two-dimensional drawings generated subsequently, ensuring clear operation guidance in the assembly process.

[0115] Finally, the system projects the separated components and their labeling information onto a two-dimensional plane to generate a structural exploded view. This structural exploded view not only shows the component number, assembly sequence, but also indicates the connection relationship of each component through line segments and arrows. For example, the back component is labeled with the connection line between the seat bag number and the bolt specification and tightening torque parameters, realizing the complete conversion of three-dimensional assembly logic to two-dimensional process drawings

[0116] Through the above steps, the system realizes the complete logical chain of "assembly constraint identification - hierarchical disassembly - label generation - two-dimensional projection", ensuring that the output structural exploded view not only truly reflects the three-dimensional assembly logic, but also meets the requirements of process drawings for accuracy and operability.

[0117] Further, the computing consumable usage and loss coefficient step includes:

[0118] Extracting volume data and surface area data of each component from the three-dimensional structure model;

[0119] According to the material type of the component, query the corresponding density parameter, thickness specification and standard plate size in the material database;

[0120] Calculate the weight of solid materials based on the volume of components and the density of materials, and calculate the area requirement of sheet materials based on the surface area and the thickness of materials;

[0121] Set the corresponding processing loss coefficient according to the material type, including cutting loss, corner loss and process loss;

[0122] Multiply the actual demand quantity by the loss coefficient to obtain the total material consumption, and perform integer number taking and specification matching according to the material specification;

[0123] Specifically, the system automatically completes the material consumption calculation and loss coefficient correction after generating the three-dimensional structure model. The volume data and surface area data of each component are directly extracted from the three-dimensional model. The volume is used to calculate the solid material requirement, and the surface area is combined with the thickness to calculate the sheet material area requirement.

[0124] The system retrieves the corresponding parameters in the material database according to the material type of the component. The database pre-stores density, thickness, standard sheet material specification and processing characteristics. For wooden components, the system calculates the theoretical weight based on the volume and density parameters, and then matches the standard sheet thickness to determine the actual sheet material consumption. For leather and cloth coverings, the system calculates the unfolded area requirement based on the surface area, combined with the thickness and width parameters.

[0125] After calculating the theoretical requirement, the system calls the corresponding loss coefficient according to the material type. The loss coefficient includes cutting loss, corner loss and process loss. The cutting loss is determined by the tool path width and the number of cuts, the corner loss is determined by the area of the non-usable area during the unfolding and material arrangement, and the process loss is determined by the preset fixed proportion of sewing, punching and edge folding processes. The system multiplies the actual demand quantity by the loss coefficient to obtain the corrected total material consumption.

[0126] After the total material consumption is calculated, the system performs integer number taking and specification matching by comparing with the standard specifications in the material database. Sheet materials use whole specifications for calculation, and the output is the number of sheets and the specification model. Roll materials use width and length combination for integer taking, and the output is the length requirement of the roll material. The final generated material list includes component number, material name, specification model, quantity, unit weight and loss ratio, and is accompanied by a total consumption statistics table.

[0127] This embodiment ensures that the material list is both purchasable and reflects the actual production and processing loss, providing a reliable basis for cost accounting and procurement planning through database-driven material matching and multi-factor loss correction.

[0128] The process output module automatically annotates the two-dimensional leather pattern and structure decomposition diagram with processes to form a digital process document that can be directly used for production.

[0129] Further, the automatic process annotation step includes:

[0130] Geometric analysis is performed on the contour boundary of the two-dimensional leather pattern to identify straight line segments, arc line segments, and inflection point positions, and dimension marking points are automatically inserted on the boundary at a preset interval;

[0131] According to the material properties and thickness parameters of the leather pattern, seam allowance width values and sewing process symbols are marked at the seam boundary positions;

[0132] The components in the structural exploded view are classified according to material type, and processing tolerance ranges are marked on wooden components, and welding symbols and surface treatment requirements are marked on metal components;

[0133] The assembly constraint relationships between components are extracted, and bolt specifications, hole diameter sizes, and tightening torque values are marked at the connection positions;

[0134] The two-dimensional leather pattern and the structural exploded view with completed marking are generated into a unified format digital process document according to unified format requirements.

[0135] Specifically, the system automatically performs process marking procedures after generating the two-dimensional leather pattern and the structural exploded view. For the outer contour of the leather pattern, the system performs geometric analysis to identify straight line segments, arc line segments, and inflection point positions, inserts dimension marking points on the boundary at a preset interval, and automatically generates dimension marking lines and values. For boundaries involving sewing, the system determines the seam allowance width according to the material properties and thickness parameters, and adds the sewing symbol at the corresponding position to ensure consistency of the cutting and sewing processes.

[0136] The process marking of the structural exploded view is based on component type classification. Wooden components are marked with processing tolerance ranges at the same time to indicate the processing allowable deviation; metal components are marked with welding symbols at the connection boundaries and with spraying or electroplating requirements at the surface treatment areas; for components that need to be assembled by bolts, the system marks the hole diameter, bolt specification, and tightening torque at the connection hole positions. All marking symbols follow the drawing specification of the furniture manufacturing industry standard to avoid manual interpretation differences.

[0137] After marking is completed, the system combines the two-dimensional leather pattern and the structural exploded view into a unified digital process document, which contains component codes, dimension markings, process symbols, and material information. The output format is a standardized vector file, which supports DXF and PDF dual-format storage, and can be used for direct calling of numerical control equipment and is convenient for production workers to view.

[0138] This embodiment converts the traditional manual marking process into a standardized output through automatic geometric analysis and rule-driven symbol generation, improving the accuracy and consistency of the drawings and shortening the process design cycle.

[0139] Example Two:

[0140] An enterprise received an order of customized three-seater sofa bed, the customer required the appearance size of 2000mm×950mm×900mm, the armrest used streamline curved surface, the fabric was directional hemp cloth, and 20 sets needed to be delivered within 15 days.

[0141] In the traditional way, the enterprise needed to manually draw the sample, disassemble the parts and calculate the material consumption by experienced workers. The whole sample drawing process took at least 3-4 days, and the sample accuracy depended on the experience of the workers, with a high error rate, often resulting in rework, which prolonged the development cycle.

[0142] Using the fast modeling system for sofa bed digital sample drawing of the application, the process is realized as Figure 2 The designer inputs the appearance parameters on the CAD platform, and the system automatically completes the parameterization definition of the seat bag, backrest, armrest and bottom frame, and generates a three-dimensional structure model on the SolidWorks platform. The complex curved armrest and backrest are unfolded into a two-dimensional leather pattern by the energy minimization algorithm, and the system automatically optimizes the layout scheme to make the fabric utilization rate reach more than 88%. During the layout process, the system automatically adjusts the component layout according to the fabric width and the matching requirements to avoid manual trial and error.

[0143] The component library and material database automatically complete the matching of standard parts: the armrest connector is matched to "angle code-50×50×2.0-SPCC", the bottom frame is selected as "18mm plywood", and the fabric is bound to "hemp-warp 1450mm". The system synchronously generates a consumable list, clearly indicating the number of boards, fabric meters and metal parts, and considers the loss correction. The structural exploded view is automatically labeled with part numbers and assembly sequence, and the process output module generates a digital process document with seam symbols, hole diameter annotations and tolerance specifications, and exports a DXF file for direct calling by a numerical cutting machine.

[0144] Through the system, the enterprise completed the whole sample drawing and process file output within 8 hours, with a consumable calculation error rate of less than 2%. Compared with traditional manual sample drawing, the product development cycle is shortened by about 75%, the sample drawing cost is reduced by 40%, the sample consistency and assembly accuracy are significantly improved, and the timely delivery of the order is ensured.

[0145] Finally, it should be noted that the above description is only a preferred embodiment of the application and is not intended to limit the application. Although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some technical features. Any modification, equivalent substitution, improvement, etc. made within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A rapid modeling system for digital pattern making of sofas and upholstered beds, characterized in that, include: The modeling platform module, based on a 3D parametric modeling platform, receives images or design inputs of sofa and soft bed products and performs parametric definitions for seat cushions, backrests, armrests, bottom frames, support structures, and connecting components. The 3D modeling and 2D unfolding module generates a 3D structural model based on the parameterized definition, unfolds a complex curved surface based on the surface flattening algorithm, and generates 2D leather and fabric pattern data that conforms to the cutting process by combining splicing optimization strategy. The component library and material database are used to store standardized component models and material specifications. During the modeling process, the system calls the corresponding components and matches them with the material parameters. The structural disassembly and consumable statistics module generates a structural decomposition diagram that conforms to production standards based on the three-dimensional structural model, dynamically matches the optimal material specifications based on the material database, calculates the amount of consumables used and the loss coefficient, and outputs a complete list of consumables. The process output module automatically annotates the two-dimensional fabric plate and the exploded structural diagram to generate a digital process document that can be directly used for production.

2. The rapid modeling system for digital pattern making of sofas and upholstered beds according to claim 1, characterized in that, The parameterization definition includes: Obtain the component outline from the input image or design file, select reference points on the outline, and establish a reference line; Based on the reference points and reference lines, the length and width dimensions, surface curvature parameters, and connection position parameters of the components are set. The parameters are solidified into a parametric modeling file for the component, which can be used for subsequent 3D modeling.

3. The rapid modeling system for digital pattern making of sofas and upholstered beds according to claim 1, characterized in that, The process of generating the three-dimensional structural model includes the following steps: Import the component parametric modeling file into the 3D parametric modeling platform, and generate the basic geometric framework based on the component's dimensional parameters; The parametric modeling file is called on the geometric framework to form a complete component surface model; The component surface model is imported into a 3D parametric modeling platform. Based on interface features and assembly constraints, the mating relationship is automatically established, and the components are assembled in the assembly sequence to form a 3D structural model of the sofa bed.

4. The rapid modeling system for digital pattern making of sofas and upholstered beds according to claim 1, characterized in that, The surface flattening algorithm for unfolding complex surfaces includes the following steps: The surface of the part to be unfolded is divided into Delaunay triangular meshes, and the area deformation energy of each triangular element is calculated. Establish a set of optimization equations with the objective function of minimizing the total deformation energy; The conjugate gradient method is used to solve for the two-dimensional planar coordinates of the mesh nodes; Two-dimensional contour lines and internal construction lines are generated based on the unfolded results.

5. A rapid modeling system for digital pattern making of sofas and upholstered beds according to claim 1, characterized in that, The splicing optimization strategy includes: Boundary recognition is performed on the outlines of all unfolded two-dimensional components. The splicing matching of adjacent components is performed based on the shape of the outline edge. During the splicing of the two-dimensional leather and fabric plates, the splicing priority is established based on the curvature continuity of the component boundaries, the material texture direction, and the process stress constraints. The optimal splicing path is determined through a global optimization algorithm.

6. A rapid modeling system for digital pattern making of sofas and upholstered beds according to claim 1, characterized in that, The step of calling the corresponding component and matching it with the material parameters includes: Extract the geometric feature parameters and dimensional constraints of the components, and retrieve the matching standardized component models in the component library according to geometric similarity; Candidate materials are selected from the material database based on the material requirements specifications of the component model; The material specifications with the highest scores are selected and bound to the component model based on a weighted sorting of three fields: cost, thickness matching degree, and tensile strength.

7. A rapid modeling system for digital pattern making of sofas and upholstered beds according to claim 1, characterized in that, The steps for generating the exploded structural diagram include: Based on the 3D structural model, the connection constraints and positional constraints between each component are extracted to form a constraint map; The components are separated step by step according to the hierarchical order of the constraint diagram, and the connection hole positions, installation directions and assembly numbers are marked on the surface of the separated components; The separation results and constraint relationships are projected onto a two-dimensional plane to generate a structural exploded diagram containing component numbers, assembly sequence, and connection relationships.

8. A rapid modeling system for digital pattern making of sofas and upholstered beds according to claim 1, characterized in that, The steps for calculating consumable usage and loss coefficient include: Extract the volume and surface area data of each component from the three-dimensional structural model; Based on the material type of the component, query the corresponding density parameters, thickness specifications, and standard sheet metal dimensions in the material database; The weight of the solid material is calculated based on the component volume and material density, and the area requirement of the sheet material is calculated based on the surface area and material thickness. Set the corresponding processing loss coefficient according to the material type, including cutting loss, edge loss and process loss; The total material consumption is obtained by multiplying the actual demand by the loss factor, and then rounding the quantity and matching the specifications according to the material specifications.

9. A rapid modeling system for digital pattern making of sofas and upholstered beds according to claim 1, characterized in that, The automated process labeling steps include: Geometric analysis is performed on the outline boundary of the two-dimensional leather and fabric plate to identify straight line segments, arc segments and inflection point positions, and dimension annotation points are automatically inserted on the boundary at preset intervals; Based on the material properties and thickness parameters of the leather and fabric pattern, mark the seam width value and sewing process symbols at the seam boundary; The components in the exploded structural diagram are classified according to material type. The machining tolerance range is marked on the wooden components, and the welding symbols and surface treatment requirements are marked on the metal components. Extract the assembly constraints between components, and mark the bolt specifications, hole diameter, and tightening torque values ​​at the connection locations; The annotated two-dimensional fabric template and structural exploded view are used to generate a digital process document in a unified format according to the unified format requirements.

Images