Lightweight processing method for three-dimensional model

Abstract

The invention provides a lightweight processing method for a three-dimensional model, and belongs to the technical field of three-dimensional model processing, and the method comprises the following steps: S1, importing the three-dimensional model into three-dimensional software, traversing each part of the three-dimensional model by the three-dimensional software, and obtaining the type of each part, the types including a grid type, a curved surface type, an entity type and a point type; calculating the part surface area of each grid type or curved surface type; s2, calculating a standardized surface area G; s3, calculating the ratio of each grid type part or curved surface type part to the standardized surface area G, and setting a ratio threshold value L; comparing the ratio of each grid type part or curved surface type part to the standardized surface area G with a proportion threshold value L, and deleting the corresponding part according to a comparison result; according to the method, the grid type part and the curved surface type are considered, and the visual continuity is ensured while the precision of the three-dimensional model is ensured.

Description

Technical Field

[0001] This invention belongs to the field of 3D model processing technology, specifically relating to a lightweight processing method for 3D models. Background Technology

[0002] In the digital production process of a factory, the conversion of two-dimensional drawings into three-dimensional models is a crucial link between the design and production ends. Through this conversion, the abstract dimensions and geometric information on the two-dimensional drawings can be transformed into an intuitive three-dimensional solid model, helping factory technicians and operators to understand the design intent more accurately. This effectively reduces processing misunderstandings and production errors caused by errors in the interpretation of drawings, and provides accurate basis for subsequent parts processing, assembly, and debugging.

[0003] However, in practical applications, the models in 3D model databases often have complex structures and large data volumes. When factories need to import these models into 3D software and combine them into large 3D scenes covering multiple parts (such as models of an entire piece of equipment or an entire production line), excessively long loading times, software lag, or even crashes often occur, seriously affecting the efficiency of design verification, process disclosure, and production collaboration.

[0004] To address this issue, various methods for lightweighting 3D models have emerged in the prior art, such as the "Method, System, Device, and Storage Medium for Supporting Lightweight Processing and Lossless Compression of Multi-Dimensional 3D Models" disclosed in patent application number 202510014482.4. However, these methods generally suffer from a key flaw: they fail to consider the geometric differences between parts in the 3D model and unify the processing of mesh-type parts and curved-surface-type parts. In fact, the core value of mesh-type parts lies in the fine representation of model details (such as the edges and grooves of parts) through discrete facets, while curved-surface-type parts rely on continuous mathematical surface definitions to ensure the smoothness and geometric continuity of the model (such as equipment shells and streamlined structures). Ignoring the essential differences between the two types of parts for unified lightweighting makes it difficult to simplify the model data volume while simultaneously considering the model accuracy (such as assembly tolerance requirements) and visual continuity (such as the intuitiveness of the model during process briefings) required for factory production, ultimately affecting the application value of the lightweight model in actual production scenarios. Summary of the Invention

[0005] This invention proposes a lightweight processing method for 3D models, taking into account the differences between mesh type and surface type parts, so as to ensure the accuracy and visual continuity of the constructed large 3D structure while reducing weight.

[0006] To achieve the above objectives, the present invention proposes the following technical content:

[0007] A lightweight processing method for 3D models includes the following steps:

[0008] S1: Import the 3D model into the 3D software. The 3D software iterates through each part of the 3D model to obtain the type of each part, which includes: mesh type, surface type, solid type, and point type; calculate the surface area of ​​each mesh type or surface type part.

[0009] S2: Calculate the standardized surface area G; specifically including the following steps:

[0010] S2.1: Calculate the sum of the surface areas of all curved surface type parts, set as A, and the sum of the surface areas of all mesh type parts, set as B, and calculate the weights of the surface areas of curved surface type parts and mesh type parts;

[0011] S2.2: Calculate the normalized surface area G based on the weights of the surface areas of curved surface type parts and mesh type parts;

[0012] S3: Calculate the ratio of each mesh type part or surface type part to the standardized surface area G, and set a ratio threshold L; compare the ratio of each mesh type part or surface type part to the standardized surface area G with the ratio threshold L, and delete the corresponding part based on the comparison result; specifically, this includes the following steps:

[0013] S3.1: Calculate the ratio of each mesh type part or surface type part to the normalized surface area G;

[0014] S3.2: Compare the ratio in S3.1 with the set threshold L. Based on the comparison result, delete mesh-type parts or surface-type parts that are less than or equal to the threshold L to obtain the processed 3D model.

[0015] 1. By incorporating the surface area of ​​different types of parts (curved surfaces and meshes) into a unified evaluation system through "standardized surface area G", the problem of "large differences in geometric properties between curved surfaces and meshes, making direct comparison difficult" is solved.

[0016] 2. The introduction of "weight allocation" and "proportion threshold L" makes the screening process quantifiable and controllable (e.g., controlling the degree of lightweighting by adjusting the L value), suitable for scenarios with different precision requirements (such as high-fidelity display, quick preview, etc.).

[0017] Furthermore, the formulas for calculating the surface area weights of A, B, and curved surface type parts, and the surface area weights of mesh type parts are as follows:

[0018]

[0019] In the formula, A represents the sum of the surface areas of all curved surface types of parts; S 1，j S represents the surface area of ​​the j-th surface type part; B represents the sum of the surface areas of all mesh type parts; 2，mThe surface area of ​​the m-th mesh type part is represented by x; x and y represent the number of surface type parts and mesh type parts in the 3D model, respectively; ω A The weight of a surface-type part; ω B This indicates the weight of the mesh-type part; k represents a manually set reference coefficient.

[0020] By introducing weights, G is no longer simply the sum of the surface and mesh areas, but a result that comprehensively considers the relative importance of the two types of parts. This calculated G more reasonably represents the surface area scale that needs to be focused on in the entire model. When filtering parts based on the ratio of each part to G, redundant parts with lower overall model importance that can be deleted can be identified more accurately. This allows for more precise retention of core parts during lightweighting, ensuring the effectiveness and usability of the lightweighted model.

[0021] Furthermore, the formula for calculating the standardized surface area G is:

[0022] G=ω A ·A+ω B ·B

[0023] In the formula, ω A The weight of a surface-type part; ω B Indicates the weight of mesh-type parts.

[0024] Furthermore, the ratio of each mesh type part or surface type part to the normalized surface area G is expressed as:

[0025]

[0026] In the formula, Z 1，j Z represents the ratio of the j-th surface type part to the standardized surface area G; 2，m This represents the ratio of the m-th mesh type part to the normalized surface area G.

[0027] In 3D models, curved surface parts and mesh parts differ in surface area size and geometric properties. By comparing the surface area of ​​each part with its standardized surface area G, the resulting ratio Z can unify parts of different types and sizes into a quantification system based on G. This allows for the evaluation of all parts involved in the calculation (regardless of whether they are curved or mesh-based) from the perspective of "the proportion of the overall standardized surface area," providing a unified and objective basis for subsequent part selection and avoiding inconsistencies in evaluation standards due to differences in part type or original surface area size.

[0028] Furthermore, if Z 1,j ≤L=0.2 or Z 2,mIf L ≤ 0.2, then delete the j-th surface type part or the m-th mesh type part.

[0029] Setting the threshold L to 0.2 provides a clear, unified, and quantifiable criterion for part selection. The ratio Z for each surface type part... 1,j The ratio Z2,m of the mesh type parts can be quickly and objectively determined by comparing it with 0.2, thus avoiding the arbitrariness and inconsistency of subjective judgment and making the lightweighting process more standardized and repeatable.

[0030] The beneficial effects that can be achieved by adopting the above technologies are:

[0031] 1. Remove redundant parts to make the 3D model lighter, while taking into account both accuracy and visual continuity;

[0032] 2. The solution utilizes standardized surface area G, the ratio of part to G Z, and threshold L as quantitative indicators to ensure a high degree of controllability in the lightweighting process. Users can adjust the weighting coefficient k or threshold L according to actual needs to flexibly control the degree of lightweighting, balancing the lightweighting effect and information retention of the model, and meeting the needs of different scenarios (such as high-fidelity display, fast preview, etc.). Attached Figure Description

[0033] Figure 1 This is the flowchart of this solution;

[0034] Figure 2 It is the original three-dimensional model of a rock crusher in actual engineering.

[0035] Figure 3 It is a lightweight 3D model of the original 3D model. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] like Figure 1 As shown, a lightweight processing method for a 3D model includes the following steps:

[0038] S1: Import the 3D model into the 3D software. The software iterates through each part of the 3D model to obtain the type of each part, including: mesh type, surface type, solid type, and point type; calculate the surface area of ​​each mesh type or surface type part. Specifically, this includes the following steps:

[0039] S1.1: Import the 3D model into Rhino software. Assuming the 3D model has n parts, the formula for the 3D model is:

[0040] O = {O1, O2, ..., O} i ...O n}(1)

[0041] In equation (1), O represents the three-dimensional model; O i Let i represent the i-th part in the 3D model, where i∈[1,n].

[0042] S1.2: Obtain the type of each part.

[0043] The formula is:

[0044] Type i =rs.ObjectType(O i (2)

[0045] In equation (2), Type i This indicates the type of the i-th part; rs.ObjectType(*) represents the type retrieval function in Rhino software, which includes types such as surface, solid, mesh, and point.

[0046] S1.3: After obtaining the surface and mesh types of parts, calculate the surface area of ​​the two types of parts respectively; specifically, the following steps are included:

[0047] S1.3.1: Define a total of x surface-type parts and y mesh-type parts, where x + y ≤ n; renumber the x surface-type parts as {O 1，1 O 1，2 ... O 1，j ... O 1，x}, renumber the y mesh type parts, denoted as {O 2，1 O 2，2 ... O 2，m ...O 2，y};

[0048] S1.3.2: Obtain the surface area of ​​each surface-type part or mesh-type part.

[0049] The formula is:

[0050] S 1,j=rs.SurfaceArea(O 1,j (3)

[0051] In equation (3), S 1，j rs.SurfaceArea(*) represents the surface area of ​​the j-th surface type part; rs.SurfaceArea(*) represents the surface area calculation function for surface type parts in Rhino software;

[0052] S 2,m =rs.MeshArea(O 2,m (4)

[0053] In equation (4), S 2，m This represents the surface area of ​​the m-th mesh type part; rs.MeshArea(*) represents the function for calculating the surface area of ​​mesh type parts in Rhino software.

[0054] S2: Calculate the standardized surface area G. This includes the following steps:

[0055] S2.1: Calculate the sum of the surface areas of all curved surface type parts, set as A, and the sum of the surface areas of all mesh type parts, set as B, and calculate the weights of the surface areas of curved surface type parts and mesh type parts.

[0056] The formula is:

[0057]

[0058] In equation (5), A represents the sum of the surface areas of all curved surface types; B represents the sum of the surface areas of all mesh types; ω A The weight of a surface-type part; ω B This indicates the weight of the mesh-type part. k represents a manually set reference coefficient.

[0059] S2.2: Calculate the normalized surface area G based on the weights of the surface areas of curved surface type parts and mesh type parts.

[0060] The formula is:

[0061] G=ω A ·A+ω B ·B (6)

[0062] In equation (6), ω A The weight of a surface-type part; ω B A represents the weight of mesh type parts; B represents the sum of the surface areas of all surface type parts; G represents the normalized surface area.

[0063] S3: Calculate the ratio of each mesh type part or surface type part to the standardized surface area G, and set a scaling threshold L; compare the ratio of each mesh type part or surface type part to the standardized surface area G with the scaling threshold L, and delete the corresponding part based on the comparison result. Specifically, this includes the following steps:

[0064] S3.1: Calculate the ratio of each mesh type part or surface type part to the normalized surface area G.

[0065]

[0066] In equation (7), Z 1，j Z represents the ratio of the j-th surface type part to the standardized surface area G; 2，m This represents the ratio of the m-th mesh type part to the normalized surface area G.

[0067] S3.2: Move Z 1，j Or Z 2，m Compared to L = 0.2, if Z 1,j ≤L=0.2 or Z 2,m If L ≤ 0.2, then delete the j-th surface type part or the m-th mesh type part. After deleting the part, re-import the 3D model into the 3D database. This will reduce loading time and improve efficiency when calling the 3D model during the construction of large 3D scenes.

[0068] Calculation example:

[0069] The original 3D model of the rock crusher used in a certain rock engineering project is shown below. Figure 2 The 3D model processed by this method is shown below. Figure 3 , Figure 3 Compared to Figure 2 Removed Figure 2 The model contains a large number of screw parts. The original 3D model and the processed 3D model were imported into 3D software to obtain their relevant parameters, as shown in Table 1.

[0070] Table 1 Comparison of parameter values ​​of the 3D models before and after lightweighting.

[0071]

[0072]

[0073] As can be seen from the data in Table 1, the 3D model after lightweight processing is far inferior to the original model in terms of processing effect, including the required computing resources and loading time. Moreover, the texture mapping deviation is less than 3 pixels, which is imperceptible to the human eye, indicating high visual continuity.

[0074] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A lightweight processing method for three-dimensional models, characterized in that, Includes the following steps: S1: Import the 3D model into the 3D software. The 3D software iterates through each part of the 3D model to obtain the type of each part, which includes: mesh type, surface type, solid type, and point type; calculate the surface area of ​​each mesh type or surface type part. S2: Calculate the standardized surface area G; specifically including the following steps: S2.1: Calculate the sum of the surface areas of all curved surface type parts, set as A, and the sum of the surface areas of all mesh type parts, set as B, and calculate the weights of the surface areas of curved surface type parts and mesh type parts; S2.2: Calculate the normalized surface area G based on the weights of the surface areas of curved surface type parts and mesh type parts; S3: Calculate the ratio of each mesh type part or surface type part to the standardized surface area G, and set a ratio threshold L; compare the ratio of each mesh type part or surface type part to the standardized surface area G with the ratio threshold L, and delete the corresponding part based on the comparison result; specifically, this includes the following steps: S3.1: Calculate the ratio of each mesh type part or surface type part to the normalized surface area G; S3.2: Compare the ratio in S3.1 with the set threshold L. Based on the comparison result, delete mesh-type parts or surface-type parts that are less than or equal to the threshold L to obtain the processed 3D model.

2. The lightweight processing method for a three-dimensional model according to claim 1, characterized in that, In step S2.1, the formulas for calculating the surface area weights of A, B, surface type parts, and mesh type parts are as follows: In the formula, A represents the sum of the surface areas of all curved surface types of parts; S 1，j S represents the surface area of ​​the j-th surface type part; B represents the sum of the surface areas of all mesh type parts; 2，m The surface area of ​​the m-th mesh type part is represented by x; x and y represent the number of surface type parts and mesh type parts in the 3D model, respectively; ω A The weight of a surface-type part; ω B This indicates the weight of the mesh-type part; k represents a manually set reference coefficient.

3. The lightweight processing method for a three-dimensional model according to claim 2, characterized in that, In step S2.2, the formula for calculating the standardized surface area G is: G=ω A ·A+ω B ·B In the formula, ω A The weight of a surface-type part; ω B Indicates the weight of mesh-type parts.

4. The lightweight processing method for a three-dimensional model according to claim 1, characterized in that, In step S3.1, the ratio of each mesh type part or surface type part to the normalized surface area G is expressed as: In the formula, Z 1，j Z represents the ratio of the j-th surface type part to the standardized surface area G; 2，m This represents the ratio of the m-th mesh type part to the normalized surface area G.

5. The lightweight processing method for a three-dimensional model according to claim 4, characterized in that, In step S3.2, if Z 1,j ≤L=0.2 or Z 2,m If L ≤ 0.2, then delete the j-th surface type part or the m-th mesh type part.

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