CAD three-dimensional model variable modeling method, device, electronic equipment and medium

Abstract

The present invention proposes a CAD three-dimensional model variable modeling method, device, electronic device and medium. The method includes: establishing primitive nodes for representing the three-dimensional model in a three-dimensional model design scene; converting design constraints into constraint relationships between primitive nodes to build a variable modeling system; converting the system into a solvable algebraic equation form; and decomposing it into multiple subsystems in the form of algebraic equations according to a preset algorithm; solving each subsystem to obtain a corresponding solution; based on the corresponding solution of each subsystem, assembling and combining according to the constraint relationships between the subsystems, thereby completing the solution of the variable modeling system. The present invention uniformly defines the dimensional parameters and engineering relationships in the modeling process using constraint variable statements, considers the composition of the entire three-dimensional model as a complete system, eliminates the sequential correlation with the model construction process, and realizes a new CAD three-dimensional model design process and method.

Description

Technical Field

[0001] The present application relates to the technical field of three-dimensional model design, and in particular to a method, device, electronic equipment and medium for variable modeling of CAD three-dimensional models. Background Art

[0002] In CAD 3D model design applications, parametric modeling is a key core process. Parametric modeling is a bottom-up design process that layers design evolution on top of historical model features to impose design constraints, match design goals, and complete the final design solution.

[0003] Traditional parametric modeling technology solves the problem of updating model graphics under geometric constraints. The expression is that the dimensions drive the geometric shape changes. By defining the input dimensions / variables of the features in parametric modeling as parameters or expressions, and establishing associations and references between parameters of different features, a complete parametric system is constructed. In the case of subsequent parameter updates, the entire 3D model is driven to update in a cascade. The defects and shortcomings of existing technologies include:

[0004] The calculation of the parametric modeling system is procedural and strictly follows the historical order of features. The system consists of a series of feature calculation nodes with clear dependencies. As a result, the parametric system cannot handle the situation where there are circular dependencies between features: it can only handle the dependency of subsequent features on previous features, but cannot handle the dependency of previous features on subsequent features.

[0005] In addition, parametric modeling systems can only handle dimension-driven model shape changes. All editable / updatable variables in parametric modeling systems must be clearly defined dimensions, or parameters / expressions related to dimensions. They cannot handle more general engineering constraints other than dimensional variables, such as the displacement deformation generated by simulation analysis calculations. Summary of the Invention

[0006] The technical solution employed by this invention considers the entire 3D model as a complete system, eliminating sequential dependencies in the model construction process while supporting both dimension-driven and constraint-driven 3D model updates. In light of this, the present invention provides a method, apparatus, electronic device, and medium for variable modeling of CAD 3D models.

[0007] The technical solution of the present invention proposes a CAD three-dimensional model variable modeling method, comprising:

[0008] Step S1, in a three-dimensional model design scene, establishing a primitive node for representing the three-dimensional model;

[0009] Step S2, converting the design constraints configured by the user into constraint relationships between the primitive nodes to construct a variable modeling system;

[0010] Step S3, converting the variable modeling system into a solvable algebraic equation form;

[0011] Step S4, decomposing the variable modeling system into a plurality of subsystems in the form of solvable algebraic equations according to a preset algorithm;

[0012] Step S5, solving each of the subsystems to obtain a corresponding solution;

[0013] Step S6: Based on the corresponding solution of each of the subsystems, assembling and combining are performed according to the constraint relationship between the subsystems, thereby completing the solution of the variable modeling system.

[0014] In one embodiment, the primitive node includes:

[0015] The geometric points / edges / surfaces of the three-dimensional model, and the model feature nodes.

[0016] In one embodiment, the constraint relationship includes both geometric constraints and engineering constraints.

[0017] In one embodiment, converting the primitive nodes and the constraint relationships in the variable modeling system into a solvable algebraic equation form includes:

[0018] The primitive nodes in the modeling system are converted into variable mathematical expressions through algebraic and geometric definitions;

[0019] The constraint relationship between the nodes is combined with the variable expression of the nodes themselves and converted into an algebraic equation form.

[0020] In one embodiment, decomposing the variational modeling system into a plurality of subsystems in the form of solvable algebraic equations according to a preset algorithm includes:

[0021] The variable modeling system is decomposed into a plurality of subsystems in the form of solvable algebraic equations according to a preset algorithm using a graph-based structural decomposition method or a rule-based definition method.

[0022] In one embodiment, solving each of the subsystems to obtain a corresponding solution includes:

[0023] Numerical iterative algorithms and / or algebraic symbolic computations.

[0024] In one embodiment, the assembling and combining the subsystems based on the corresponding solutions of the subsystems according to the constraint relationships between the subsystems, thereby completing the solution of the variational modeling system, includes:

[0025] According to the constraints of the subsystems, the subsystems are recursively merged to complete the model solution of the variable modeling system.

[0026] Another aspect of the present invention provides a CAD three-dimensional model variable modeling device, comprising:

[0027] A node construction unit configured to establish a primitive node for representing the three-dimensional model in a three-dimensional model design scene;

[0028] A constraint construction unit configured to convert the design constraints configured by the user into constraint relationships between the primitive nodes to construct a variable modeling system;

[0029] a conversion unit configured to convert the variable modeling system into a solvable algebraic equation form;

[0030] a decomposition unit configured to decompose the variable modeling system into a plurality of subsystems in the form of solvable algebraic equations according to a preset algorithm;

[0031] A solving unit, configured to solve each of the subsystems to obtain a corresponding solution;

[0032] The output unit is configured to assemble and combine the subsystems based on the corresponding solution of each subsystem and the constraint relationship between the subsystems, thereby completing the solution of the variable modeling system.

[0033] Another aspect of the present invention provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor is configured to execute the computer program to implement the CAD three-dimensional model variable modeling method as described in any one of the above items.

[0034] Another aspect of the present invention further provides a computer-readable storage medium, wherein the medium stores a computer program, and the computer program is executed to implement the CAD three-dimensional model variable modeling method as described in any one of the above items.

[0035] By adopting the above technical solution, the present invention has at least the following advantages:

[0036] The present invention uniformly defines the dimensional parameters and engineering relationships in the modeling process using constraint variable declarative definitions, considers the composition of the entire three-dimensional model as a complete system, eliminates the sequential correlation with the model construction process, and supports dimension-driven and constraint-driven three-dimensional model updates, thereby realizing a new CAD three-dimensional model design process and method. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0038] Figure 1 A schematic diagram of a process for variable modeling of a CAD three-dimensional model according to an embodiment of the present invention;

[0039] Figure 2 A schematic diagram of nodes and constraints in a variable modeling system corresponding to a piston, crankshaft, and connecting rod mechanism model according to an embodiment of the present invention;

[0040] Figure 3 A schematic diagram of a swept surface, a contour curve, and a path curve according to an embodiment of the present invention;

[0041] Figure 4 Schematic diagram of warping deformation of a curve under different deformation functions, different warping directions and different warping distances according to an embodiment of the present invention;

[0042] Figure 5 Based on Figure 1 The graph structure corresponding to the variable modeling system;

[0043] Figure 6 Based on Figure 5 The constraint graph is decomposed into two subgraph structures;

[0044] Figure 7 A diagram related to the construction process sequence of existing parametric modeling system technical solutions;

[0045] Figure 8 A sequence-independent diagram of a process of a variable modeling system according to an embodiment of the present invention;

[0046] Figure 9 A schematic diagram of the construction and execution process of a variational modeling system according to an embodiment of the present invention;

[0047] Figure 10 Schematic diagram of the composition of a CAD three-dimensional model variable modeling device according to an embodiment of the present invention;

[0048] Figure 11 FIG. 1 is a schematic diagram of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose, the present invention is described in detail below with reference to the accompanying drawings and preferred embodiments.

[0050] Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art. The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0051] The first embodiment of the present invention is a method for variable modeling of a CAD three-dimensional model, such as Figure 1 As shown, the following steps are included:

[0052] Step S1, in a three-dimensional model design scene, establishing a primitive node for representing the three-dimensional model;

[0053] Step S2, converting the design constraints configured by the user into constraint relationships between the primitive nodes to construct a variable modeling system;

[0054] Step S3, converting the variable modeling system into a solvable algebraic equation form;

[0055] Step S4, decomposing the variable modeling system into a plurality of subsystems in the form of solvable algebraic equations according to a preset algorithm;

[0056] Step S5, solving each of the subsystems to obtain a corresponding solution;

[0057] Step S6: Based on the corresponding solution of each of the subsystems, assembling and combining are performed according to the constraint relationship between the subsystems, thereby completing the solution of the variable modeling system.

[0058] In this embodiment, the primitive node includes:

[0059] The geometric points / edges / surfaces of the three-dimensional model, and the model feature nodes.

[0060] In this embodiment, converting the primitive nodes and the constraint relationships in the variable modeling system into a solvable algebraic equation form includes:

[0061] The primitive nodes in the modeling system are converted into variable mathematical expressions through algebraic and geometric definitions;

[0062] The constraint relationship between the nodes is combined with the variable expression of the nodes themselves and converted into an algebraic equation form.

[0063] In this embodiment, the variable modeling system is decomposed into a plurality of subsystems in the form of solvable algebraic equations according to a preset algorithm, including:

[0064] The variable modeling system is decomposed into a plurality of subsystems in the form of solvable algebraic equations according to a preset algorithm using a graph-based structural decomposition method or a rule-based definition method.

[0065] In this embodiment, solving each of the subsystems to obtain a corresponding solution includes:

[0066] Numerical iterative algorithms and / or algebraic symbolic computations.

[0067] In this embodiment, the assembling and combining of the subsystems based on the corresponding solutions of each subsystem and the constraint relationships between the subsystems, thereby solving the variational modeling system, includes:

[0068] According to the constraints of the subsystems, the subsystems are recursively merged to complete the model solution of the variable modeling system.

[0069] The method provided in this embodiment will be described in detail below.

[0070] This embodiment specifically proposes a new CAD 3D modeling system and method for variable modeling. This variable modeling system considers the entire 3D model as a complete system, independent of the order of the model's construction process. The geometry and model feature definition dimensions, as well as the engineering relationships defined by the user during the modeling and design process, are uniformly represented using constraints and stored as variables in the system. The definition process and calculation methods of this system and method are as follows:

[0071] Variable modeling system definition:

[0072] Definition 1: Using a graph To represent a variable modeling system, where Represents the collection of all geometry / feature / model body nodes in the variant modeling system. Represents the set of all constraints in a variable modeling system (including dimensional variables and more general engineering constraints). It is called the constraint diagram of the variational modeling system.

[0073] Constraint definition:

[0074] Constraints are defined as design restrictions in the 3D model design process. Depending on the constraint properties, constraints can be divided into geometric constraints and engineering constraints. Geometric constraints are restrictions on the position, attributes, and shape of variable geometry, used to ensure the feasibility and effectiveness of the construction and modification of 3D geometric models. Geometric constraints are divided into dimensional constraints (length / radius / distance / angle, etc.) and logical constraints (parallel / perpendicular / tangent, etc.). Engineering constraints refer to the requirements or technical indicators that should be achieved for the design of 3D models in terms of product function, product performance, process, materials, manufacturing, assembly, etc. Engineering constraints have no direct relationship with the composition of the geometric model and need to be converted or decomposed into geometric constraints before being applied to the 3D model.

[0075] The process of building a variable modeling system:

[0076] First, in the 3D model design process, the primitive nodes related to geometric modeling in the model construction are established: geometric points / edges / faces, model feature nodes, and 3D model bodies, etc.

[0077] The design restrictions added by the user during the 3D model design process are then converted into constraint relationships between the above-mentioned graphic nodes to form a complete variable modeling system.

[0078] refer to Figure 2 , the nodes and constraints in the variable modeling system corresponding to the piston, crankshaft and connecting rod mechanism model, which will point Along a straight line The translation motion is converted into a point In the center of and the radius is Rotational motion on a circular path, where The range of motion is and between, All four points are on a straight line superior.

[0079] refer to Figure 3 as well as Figure 4 While building the above variable modeling system, it is necessary to convert the modeling system into a solvable system, which involves:

[0080] First, the primitive nodes in the modeling system are transformed into variable mathematical expressions through algebraic and geometric definitions: the basic modeling methods in solid / surface modeling can be uniformly described as input contour curves, which move along a certain path. The three-dimensional space area enclosed during the movement is the boundary of the three-dimensional model. For example, for a given contour curve , path curve The swept modeling, the model boundary surface enclosed by the sweep can be defined as ,in is a The matrix is the contour curve On the path curve Parameter domain The rotation and scaling transformation applied at any point

[0081] Second, the constraints between nodes are combined with the variable expressions of the nodes themselves and transformed into algebraic equations:

[0082] For example, the warpage of the model calculated by CAE simulation analysis can be used to reversely drive the design of the CAD model. This means that the warpage can be applied to the geometric model design to constrain the generation of the model's geometric surface. The specific calculation form of the surface algebraic equation can be briefly summarized as the equation ; among them is a function, is a constant, It can be a function or a constant. Control warping variable function, is the maximum warping deformation distance, is the direction of warping deformation.

[0083] Through the above two steps, the variable modeling system can be converted into a solvable algebraic equation system.

[0084] Definition and process of solving the variable modeling system:

[0085] Definition 2: For a given variable modeling system , calculate one or all three-dimensional models according to a certain algorithm. Among them, this one or all three-dimensional models are composed of a set It is composed of all the geometry / feature / model body nodes in the set, and these geometry / feature / model body nodes must simultaneously satisfy the set All constraints in .

[0086] A relatively direct way to solve a variable modeling system is to convert it into a set of algebraic equations and then solve this set of equations. Since large and complex three-dimensional variable modeling systems often involve a large number of models, features, geometries, and constraints, large nonlinear equations will be generated. There is currently no complete and stable method for solving large nonlinear equations. In order to improve efficiency and reduce solution complexity, the basic idea of solving variable modeling systems is to "divide and conquer", that is, first decompose a large system into several solvable, small-scale subsystems according to a certain algorithm, and then use algebraic, numerical or geometric methods to solve each subsystem separately. Finally, according to the constraints between these subsystems, they are assembled and combined to complete the solution of the entire large system. The basic framework is as follows:

[0087] Algorithm :

[0088] Step 1: System decomposition: ... ;

[0089] a) Graph-based structural decomposition methods (such as Owen's triangular decomposition method);

[0090] b) Rule-based definition methods (such as Aldefeld's geometric reasoning solution);

[0091] Step 2: Subsystem solution: Solve for the smallest subsystem. ;

[0092] a) Numerical iterative algorithms (such as the Newton-Raphson method);

[0093] b) Algebraic symbolic computation (such as the Wu-Ritt method or the Grobner basis method);

[0094] Step 3: Subsystem assembly, refer to Figures 5 and 6 : Combine the solutions of each subsystem to form the solution of the complete system, ... ;

[0095] a) Subsystem specifications;

[0096] b) Recursively merge subsystem solutions.

[0097] Combine Figures 7 to 9 The system construction and subsequent calculation logic of the present invention can be referred to as shown in the figure. Compared with the prior art, the advantages of the variable modeling system and method proposed in this patent scheme include at least the following:

[0098] 1) In the variable modeling system, dimensional parameters and engineering relationships in the modeling process are uniformly expressed using constraint variables, supporting a wider range of constraint-driven model updates, such as changes in model shape driven by engineering relationships, and better supporting the structural design and optimization of 3D model products;

[0099] 2) In the variable modeling system, constraints in the modeling process are defined declaratively rather than procedurally, supporting arbitrary dependencies between 3D model design features. This greatly increases the designer's design freedom and helps them generate more creative design solutions.

[0100] In summary, this embodiment proposes a new CAD three-dimensional model variable modeling system and method. By uniformly defining the dimensional parameters and engineering relationships in the modeling process using constraint variable declarative definitions, the entire three-dimensional model composition is considered as a complete system, eliminating the sequential correlation with the model construction process, and supporting dimension-driven and constraint-driven three-dimensional model updates, thereby realizing a new CAD three-dimensional model design process and method.

[0101] The second embodiment of the present invention corresponds to the first embodiment. This embodiment introduces a CAD three-dimensional model variable modeling device, referring to Figure 10 , which can be understood as a physical device, including the following components:

[0102] A node construction unit configured to establish a primitive node for representing the three-dimensional model in a three-dimensional model design scene;

[0103] A constraint construction unit configured to convert the design constraints configured by the user into constraint relationships between the primitive nodes to construct a variable modeling system;

[0104] a conversion unit configured to convert the variable modeling system into a solvable algebraic equation form;

[0105] a decomposition unit configured to decompose the variable modeling system into a plurality of subsystems in the form of solvable algebraic equations according to a preset algorithm;

[0106] A solving unit, configured to solve each of the subsystems to obtain a corresponding solution;

[0107] The output unit is configured to assemble and combine the subsystems based on the corresponding solution of each subsystem and the constraint relationship between the subsystems, thereby completing the solution of the variable modeling system.

[0108] It should be noted that, in the various embodiments of the present application, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0109] The serial numbers of the above embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0110] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above embodiment methods can be implemented by means of software plus the necessary general hardware platform, or by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, or the part that contributes to the existing technology, can be embodied in the form of a software product, for example Figure 11 As shown, the computer software product is stored in a storage medium (such as ROM / RAM, disk, CD-ROM), and includes a number of instructions for enabling a terminal (which can be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in each embodiment of the present application.

[0111] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also make many forms without departing from the purpose of this application and the scope of protection of the claims, all of which are protected by this application.

Claims

1. A CAD three-dimensional model variable modeling method, characterized in that: include: Step S1, in a three-dimensional model design scene, establishing a primitive node for representing the three-dimensional model; Step S2, converting the design constraints configured by the user into constraint relationships between the primitive nodes to construct a variable modeling system; Step S3, converting the variable modeling system into a solvable algebraic equation form; Step S4, decomposing the variable modeling system into a plurality of subsystems in the form of solvable algebraic equations according to a preset algorithm; Step S5, solving each of the subsystems to obtain a corresponding solution; Step S6, based on the corresponding solution of each of the subsystems, assembling and combining according to the constraint relationship between the subsystems, thereby completing the solution of the variable modeling system; The primitive nodes include: The geometric points / edges / surfaces of the three-dimensional model, and model feature nodes; The constraint relationship also includes: geometric constraints and engineering constraints; The step of converting the primitive nodes and the constraint relationships in the variable modeling system into a solvable algebraic equation form includes: The primitive nodes in the modeling system are converted into variable mathematical expressions through algebraic and geometric definitions; Convert the constraint relationship between nodes into an algebraic equation form by combining the variable expression of the nodes themselves; The variable modeling system is decomposed into a plurality of subsystems in the form of solvable algebraic equations according to a preset algorithm, including: Decomposing the variable modeling system into multiple subsystems in the form of solvable algebraic equations according to a preset algorithm using a graph-based structural decomposition method or a rule-based definition method; Solving each of the subsystems to obtain a corresponding solution includes: Numerical iterative algorithms and / or algebraic symbolic computations; The method of assembling and combining the subsystems based on the corresponding solution of each subsystem and the constraint relationship between the subsystems to complete the solution of the variable modeling system includes: According to the constraints of the subsystems, the subsystems are recursively merged to complete the model solution of the variable modeling system.

2. A CAD three-dimensional model variable modeling device, characterized in that: include: A node construction unit configured to establish a primitive node for representing the three-dimensional model in a three-dimensional model design scene; A constraint construction unit configured to convert the design constraints configured by the user into constraint relationships between the primitive nodes to construct a variable modeling system; a conversion unit configured to convert the variable modeling system into a solvable algebraic equation form; a decomposition unit configured to decompose the variable modeling system into a plurality of subsystems in the form of solvable algebraic equations according to a preset algorithm; A solving unit, configured to solve each of the subsystems to obtain a corresponding solution; an output unit configured to assemble and combine the subsystems based on the corresponding solution of each subsystem and the constraint relationship between the subsystems, thereby completing the solution of the variational modeling system; The primitive nodes include: The geometric points / edges / surfaces of the three-dimensional model, and model feature nodes; The constraint relationship also includes: geometric constraints and engineering constraints; The conversion unit is specifically configured as follows: The primitive nodes in the modeling system are converted into variable mathematical expressions through algebraic and geometric definitions; Convert the constraint relationship between nodes into an algebraic equation form by combining the variable expression of the nodes themselves; The decomposition unit is specifically configured as follows: Decomposing the variable modeling system into multiple subsystems in the form of solvable algebraic equations according to a preset algorithm using a graph-based structural decomposition method or a rule-based definition method; The solution unit is specifically configured as follows: Numerical iterative algorithms and / or algebraic symbolic computations; The output unit is specifically configured as follows: According to the constraints of the subsystems, the subsystems are recursively merged to complete the model solution of the variable modeling system.

3. An electronic device, characterized in that: The system comprises a memory and a processor, wherein the memory stores a computer program, and the processor is configured to execute the computer program to implement the CAD three-dimensional model variable modeling method according to claim 1.

4. A computer-readable storage medium, characterized in that The medium stores a computer program, and the computer program is executed to implement the CAD three-dimensional model variable modeling method according to claim 1.

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