Three-dimensional sketch modeling method based on single-view-angle shaft control

Abstract

The invention discloses a three-dimensional sketch modeling method based on single-view axis manipulation, which comprises the following steps: reading a two-dimensional design reference drawing of a three-dimensional model, the two-dimensional design reference drawing having a clear contour; drawing a closed two-dimensional sketch contour line on a computer screen, and fitting the closed two-dimensional sketch contour line into a contour curve of the to-be-modeled part; interactively setting a posture axis of the contour; generating an initial three-dimensional model of the to-be-modeled part through a generation algorithm; adjusting the initial three-dimensional model of the to-be-modeled component through a component optimization algorithm to generate an optimized three-dimensional model of the to-be-modeled component; clicking an editing control handle on a computer screen and dragging the handle to a target position, and modifying the optimized three-dimensional model through a contour constraint-deformation algorithm; carrying out three-dimensional modeling on the next part to be modeled; and performing depth adjustment on each part model to finish modeling. Based on a single reference sketch, a user can quickly and accurately generate a three-dimensional model matched with the reference sketch through the method.

Description

Technical Field

[0001] The present invention relates to the technical field of sketch modeling, and in particular to a three-dimensional sketch modeling method based on single-view axis manipulation. Background Art

[0002] Sketching is an intuitive design language and a tool for visual communication, creative exploration, and rapid iteration. Accurately and completely representing three-dimensional objects in two-dimensional drawings often requires providing various standard views, such as front and side views. However, designing consistent and standardized standard views remains challenging. Therefore, designers often use oblique views, which present objects from non-axis-aligned perspectives and allow key features of a three-dimensional object to be captured in a single drawing. Creating models from drawings with oblique views typically requires a sketch-revolve-sketch workflow (Gingold et al., 2009). In this process, users sketch from different views to gradually build up the three-dimensional model. However, determining the most appropriate view for sketching is a challenge (Olsen et al., 2009). Furthermore, because users frequently change views to create or modify the model's shape, ensuring that the generated model's outline matches the reference image is both challenging and time-consuming during the modeling process.

[0003] To overcome the shortcomings of multi-view sketch modeling methods, some studies have focused on single-view sketch modeling methods (Bobenrieth et al., 2020; et al., 2020; Gingold et al., 2009; Guillard et al., 2021; Li et al., 2017; Long et al., 2024; Xu et al., 2014; Zhang et al., 2022). In single-view modeling methods, different shape creation algorithms and user interaction methods are used to allow shape creation without changing the view. Some methods are based on the contour rationality assumption (Buchanan et al., 2013; et al., 2020; Entem et al., 2015; Feng et al., 2017; Ramos et al., 2018). These methods assume that contours are planar and perpendicular to the view direction and directly inflate them to generate a smooth 3D mesh. However, these methods ignore non-planar contours in oblique views and have low accuracy when modeling reference sketches from arbitrary viewpoints. Some methods are based on symmetry assumptions (Buchanan et al., 2013; Entem et al., 2015; Feng et al., 2017; Guillard et al., 2021; Xue et al., 2012; Zhang et al., 2022). These methods leverage contour information and visual cues, allowing users to interactively specify additional symmetry information for each contour and solve for symmetrical shapes. However, these methods rely on symmetry assumptions and therefore have difficulty modeling asymmetric objects. Several methods have used deep learning techniques (Long et al., 2024; Sun et al., 2023; Tang et al., 2023a; Tang et al., 2023b) to generate 3D meshes from a single image. However, these generated meshes suffer from defects such as model adhesion and wrinkling, making them unsuitable for direct application to downstream tasks. Furthermore, if users are dissatisfied with the generated meshes, it is difficult to engage in the neural inference process to accurately control the results.

[0004] To address this issue, this paper proposes a novel single-view sketch modeling approach designed to seamlessly and accurately create 3D models. To ensure seamlessness, this paper combines the single-view modeling workflow with carefully designed axis tool manipulation and other interactions. To improve accuracy, this paper proposes a two-stage shape generation algorithm that ensures precise shape generation based on user sketch input and supports multi-part modification to achieve shape details and asymmetry. Summary of the Invention

[0005] The present invention provides a three-dimensional sketch modeling method based on single-view axis manipulation. Based on a single reference sketch, the user can use this method to quickly and accurately generate a three-dimensional model that matches the reference sketch.

[0006] In order to solve this technical problem, the technical solution adopted by the present invention is:

[0007] A three-dimensional sketch modeling method based on single-view axis manipulation includes the following steps:

[0008] Step S1, read in a 2D design reference drawing of a 3D model, the 2D design reference drawing must have a clear outline;

[0009] Step S2, drawing a closed two-dimensional sketch contour line on the computer screen and fitting it to the contour curve of the part to be modeled;

[0010] Step S3, interactively setting the posture axis of the contour, where the posture axis represents the three-dimensional posture of the component to be modeled;

[0011] Step S4, generating an initial three-dimensional model of the component to be modeled by a generation algorithm;

[0012] Step S5, adjusting the initial three-dimensional model of the component to be modeled by a component optimization algorithm to generate an optimized three-dimensional model of the component to be modeled;

[0013] Step S6: Click the edit control handle on the computer screen and drag the handle to the target position to modify the optimized three-dimensional model using the contour constraint-deformation algorithm;

[0014] Step S7, perform 3D modeling of the next component to be modeled, and repeat steps S2 to S7;

[0015] Step S8: perform depth adjustment on each component model to complete the modeling.

[0016] Furthermore, in step S2, the contour curve is represented by a cubic B-spline curve, which fits the contour line drawn by the user into a closed curve.

[0017] Furthermore, in step S3, the posture axis is displayed on a computer screen after the contour curve is generated, and the user sets the posture axis using an interactive adjustment method.

[0018] Furthermore, in step S4, the generation algorithm is specifically as follows: the contour curve L P Considered as the construction line L of a three-dimensional component C In the attitude axis U xyz Defined xy plane π U Orthogonal projection on the xy plane, from the perpendicular to the xy plane π U The initial three-dimensional model of the part to be modeled is obtained by expanding in the direction of .

[0019] Furthermore, in step S5, since the initial 3D model contour and the contour curve L P Incomplete matching, the component optimization algorithm is used to optimize the initial 3D model contour to match the contour curve; the component optimization algorithm is specifically to use the least squares method to minimize E sum :

[0020] argminE sum =argmin{w1E o +w2E s +w3E F +w4Ee}

[0021] Among them, w1, w2, w3, and w4 are the set weight values;

[0022] The sub-items are as follows:

[0023] Where O is the initial three-dimensional model M G The projection contour point set at the current viewing angle is obtained by the Alpha-Shape algorithm; P(·) represents the projection operation; p i Represents the projection contour point P(v i ) corresponding to the contour curve; by minimizing the sub-item E o , so that the projection contour point P(v i ) and its corresponding target point p on the contour curve i The distance between them is the smallest;

[0024] Among them, n U is the normal of the user-defined attitude axis plane, and d is the plane ∏ U The constant term in the equation, S is M G The set of symmetrical point pairs in the middle, B represents the construction line L C The set of points on ; minimize this sub-item to keep the model relative to the symmetry plane ∏ U symmetry while ensuring that mesh vertices that were originally on the central construction line remain on that line;

[0025] EF=∑i||L(vi)-δi|| 2 , Ee=∑ (i,j)∈ ε||vi-vj-ηij|| 2 , where L(·) represents the Laplace-Beltrami operator with geometric feature weights. The target Laplace value of each vertex vi is calculated as δi = Ai·ci·ni, where Ai is the 1-ring area of vertex vi, ci is the target mean curvature, and ni is the normal vector at the vertex; ei is the average edge length of vertex vi, ej is the average edge length of vertex vj, and ε is the geometry of connected vertices in the mesh;

[0026] After the component optimization algorithm, the optimized three-dimensional model is obtained.

[0027] Furthermore, in step S6, first, the center construction line and cross-section line of the model are automatically generated, and the points on the lines serve as control points for model deformation. When the user moves these points, the model will deform accordingly. The center construction line point set is directly obtained from the vertex set B on the symmetry plane. When the user uses the center construction line to deform, a deformation point vb∈B is selected on the center line of the grid, and then the point is moved on the symmetry plane according to the user's mouse movement on the screen, thereby obtaining the constraint point v' b ; The method of generating the control point set of cross-section deformation is: perform the coordinate transformation of screen projection, convert the selected point on the screen into the deformation point vs; the cross-section line is formed by the grid and the plane ∏ S The intersection calculation forms a plane that is parallel to the UxOz plane and passes through the center of the grid, thereby obtaining a point set S. When the user deforms on the cross section, the grid point closest to the point selected from the point in S on the screen is calculated, which is the user's deformation point vs. After a certain cross-sectional displacement, the constraint point v' is obtained. s ;

[0028] In addition to using the center construction line and center cross-section point sets as control handles for editing, arbitrary cross-sections are also used to generate control handle point sets for deformation. When the user selects a vertex vk located on a cross section passing through the center construction line, the plane equation of the cross section is generated using the point vk and the plane normal vector (the same as the normal vector of the center cross section). At the same time, the intersection points of the cross section with the mesh edge are calculated, and these intersection point sets are used as control handles for controlling deformation.

[0029] When the user moves the control handle, the model will deform accordingly. During the deformation process, the model's posture and projection contour remain unchanged. The contour constraint-deformation algorithm is as follows:

[0030]

[0031] Among them, w1, w2, w3, and w4 are the set weights, and flag is the symmetry mark. When creating an asymmetric model, flag will be set to 0, and when creating a symmetric model, it will be set to 1; the sub-items are:

[0032] EF is the smoothing energy term that appeared in step S5; the second term Ensure that the constraint points within the user-defined region of interest are as close as possible to the user-specified position after deformation. vi represents the value to be solved, and v' i represents the deformation position constraint point after user adjustment; Es is the symmetry constraint energy term that appeared in step S5; Eo is the contour constraint energy term that appeared in step S5; by minimizing the overall deformation energy term ED, the deformed component model is obtained.

[0033] Furthermore, in step S8, the designed control is used to control the depth of the component model, and the depth control control is moved up and down to change the depth (z coordinate value) of each component model, and the components are interactively combined to finally complete the modeling.

[0034] Beneficial effects of the present invention:

[0035] The user only needs to outline the contour of the part to be modeled according to the reference image and set its posture axis to quickly generate the corresponding three-dimensional model. The user can further edit the three-dimensional model to achieve accurate details and asymmetry, and complete the assembly of parts through depth adjustment to obtain the final modeling result. The present invention can be applied to the field of three-dimensional modeling to improve the efficiency and quality of three-dimensional modeling. The use of this technical solution reduces the comprehensibility and operational complexity of three-dimensional modeling, and can quickly generate a three-dimensional model that conforms to the input reference image. This technology can be used by professional modelers and ordinary users. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is the overall flow chart of the present invention;

[0037] Figure 2 It is a two-dimensional reference design drawing of the present invention;

[0038] Figure 3 Interactively draw and generate the contour curve of the part to be modeled for the present invention;

[0039] Figure 4 A schematic diagram of the posture axis for setting the contour curve of the present invention;

[0040] Figure 5 Generating an initial three-dimensional model diagram for the present invention;

[0041] Figure 6 Generate an optimized three-dimensional model diagram for the component optimization algorithm of the present invention;

[0042] Figure 7 This is a schematic diagram of the present invention using the control handles on the center construction line and the center cross-section line to achieve symmetrical deformation;

[0043] Figure 8 A schematic diagram of generating asymmetric deformation by controlling handle point sets at arbitrary cross sections is added to the present invention;

[0044] Figure 9 This is a schematic diagram of the depth control control of the present invention adjusting the depth of the component model;

[0045] Figure 10 This is the final modeling rendering of the present invention. DETAILED DESCRIPTION

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0047] This paper proposes a novel single-view sketch modeling approach designed to seamlessly and accurately create 3D models. To ensure seamlessness, the paper combines the single-view modeling workflow with carefully designed axis tool manipulation and other interactions. To improve accuracy, the paper proposes a two-stage shape generation algorithm that ensures precise shape generation based on user sketch input and supports multi-part modification to achieve shape details and asymmetry.

[0048] Reference Attachment Figure 1 This embodiment provides a method for automatically positioning a three-dimensional toy pattern in space, comprising the following steps:

[0049] Step S1: Read a two-dimensional design drawing into the computer, such as Figure 2 The object in the image is a 2D design of a 3D model. The image has clear outlines, making it easy for users to outline the model based on the image.

[0050] Step S2: Use a mouse, drawing pen or finger to draw a closed two-dimensional sketch contour line on the computer screen and fit it to the contour curve of the part to be modeled, such as Figure 3 The contour curve is represented by a cubic B-spline curve, which fits the contour line drawn by the user into a closed curve. McKinlay, S., Levine, M., Cubic Spline Interpolation, Math 45: Linear Algebra (McKinlay, S., Levine, M., Cubic Spline Curve, Linear Equation) website: http: / / online.redwoods.cc.ca.us / instruct / darnold / laproj / Fal198 / SkyMeg / Proj.PD F. disclosed this method.

[0051] Step S3: After the contour curve represented by the cubic B-spline is generated, the posture axis will be displayed on the computer screen, and the user can use the interactive adjustment method to set the posture axis, such as Figure 4 shown.

[0052] Step S4: Generate an initial 3D model of the component to be modeled by a component generation algorithm, such as Figure 5As shown, first, the profile curve LP is regarded as the construction line LC of the three-dimensional part in the xy plane defined by the posture axis Uxyz U Orthogonal projection on the xy plane, from the U The initial three-dimensional model of the part to be modeled is obtained by expanding in the direction of . The expansion method adopts the method disclosed by (Igarashi, 1999). W Indicates the drawing plane under the current drawing perspective, that is, the plane where the contour curve is located, which is composed of the xy axes of the world coordinate axis.

[0053] Step S5: Since the initial 3D model contour does not completely match the contour curve LP, the component optimization algorithm is used to optimize the initial 3D model contour to match the contour curve. The energy Esum is expressed as follows:

[0054] argminEsum=argmin{w1Eo+w2Es+w3EF+w4Ee}

[0055] Minimize the energy and obtain the optimized three-dimensional model, such as Figure 6 As shown in the figure, w1, w2, w3, and w4 are the set weight values; w1 is set to 1.0, w2 is set to 1.0, w3 is set to 1.0, and w4 is set to 0.01.

[0056] The sub-items are as follows:

[0057] Where O is the projected contour point set of the initial 3D model MG at the current viewpoint, obtained using the Alpha-Shape algorithm; P(·) represents the projection operation; pi represents the point on the contour curve corresponding to the projected contour point P(vi); by minimizing this sub-item Eo, the distance between the projected contour point P(vi) and its corresponding target point pi on the contour curve is minimized;

[0058] Where nU is the normal of the user-defined attitude axis plane, and d is the plane ∏ U The constant term in the equation, S is the set of symmetric point pairs in MG, and B represents the set of points on the construction line LC; minimize this sub-term to keep the model relative to the symmetry plane ∏ U symmetry while ensuring that mesh vertices that were originally on the central construction line remain on that line;

[0059] EF=∑i||L(vi)-δi|| 2 , Ee=∑ (i,j)∈ ε||vi-vj-ηij|| 2, where L(·) represents the Laplace-Beltrami operator with geometric feature weights. The target Laplace value of each vertex vi is calculated as δi = Ai·ci·ni, where Ai is the 1-ring area of vertex vi, ci is the target mean curvature, and ni is the normal vector at the vertex; ei is the average edge length of vertex vi, ej is the average edge length of vertex vj, and ε is the geometry of connected vertices in the mesh;

[0060] After the component optimization algorithm, the optimized three-dimensional model is obtained.

[0061] Step S6: If the component model needs to be further modified, first, the center construction line and cross-section line of the model will be automatically calculated and generated. The points on the line will serve as the control handle point group for model deformation. When the user interactively selects and moves one of the control handles, the model will deform accordingly. Figure 7 As shown, the user selects the two control handles vb1 and vb2 on the center construction line and moves them to v' b1 and v' b2 , at this time v' b1 and v' b2 As position constraint points, they are substituted into the ED formula for minimization. The model produces corresponding deformation effects. When observing the model from the drawing perspective, its projection outline remains unchanged. Then, the user selects a control handle vs on the center cross section line and moves it to v' s Position, at this time v' s As a constraint point, the ED formula is substituted into the minimization solution, and the model produces a corresponding deformation effect. Similarly, when observing the model from the drawing perspective, its projected outline remains unchanged. The contour constraint-deformation algorithm is specifically as follows:

[0062]

[0063] Among them, w1, w2, w3, and w4 are the set weights, and flag is the symmetry mark. In the above ED minimization solution process, the flag value is set to 1, w1 = 1.0, w2 = 0.5, w3 = 1.0, and w4 = 0.05.

[0064] Secondly, in addition to using the center construction line and center cross section point set as the control handle editing method, you can also generate a control handle point set by adding any cross section to achieve deformation. Figure 8As shown in the figure, when the user selects the vertex v1 on the cross section passing through the center construction line, the plane equation of the newly added cross section is generated using the coordinates of point v1 and the normal vector of the center cross section. At the same time, the intersection points of the cross section and the mesh edge are calculated, and these intersection points are used as control handles to control the deformation. The user selects the control handle vk1 on the newly added cross section and the center construction line control handle vk2 in turn, and moves them to v' respectively. k1 and v' k2 , and set the deformation to asymmetric deformation. At this time v' k1 and v' k2 They are used as position constraint points and substituted into the ED formula for minimization. In the above ED minimization process, the flag value is set to 0, w1 = 1.0, w2 = 0.5, w3 = 1.0, and w4 = 0.05.

[0065] Step S7: Perform 3D modeling of the next component, and repeat steps S2 to S7 until all components are modeled;

[0066] Step S8: Use Figure 9 The depth control control shown in the figure adjusts the depth of the component model. The user changes the depth of the currently selected component model (i.e. the z coordinate value in the world coordinate system) by selecting the light blue circular handle that pops up and moving it up and down. Moving the handle up means moving the current component model forward (increasing the z coordinate value); moving the handle down means moving the current component model backward (decreasing the z coordinate value). Interactively adjust each component to a reasonable depth in turn, and finally complete the modeling. The modeling effect is as follows Figure 10 shown.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A three-dimensional sketch modeling method based on single-view axis manipulation, characterized in that: The steps include: Step S1, read in a 2D design reference drawing of a 3D model, the 2D design reference drawing must have a clear outline; Step S2, drawing a closed two-dimensional sketch contour line on the computer screen and fitting it to the contour curve of the part to be modeled; Step S3, interactively setting the posture axis of the contour, where the posture axis represents the three-dimensional posture of the component to be modeled; Step S4, generating an initial three-dimensional model of the component to be modeled by a generation algorithm; Step S5, adjusting the initial three-dimensional model of the component to be modeled by a component optimization algorithm to generate an optimized three-dimensional model of the component to be modeled; Step S6: Click the edit control handle on the computer screen and drag the handle to the target position to modify the optimized three-dimensional model using the contour constraint-deformation algorithm; Step S7, perform 3D modeling of the next component to be modeled, and repeat steps S2 to S7; Step S8: perform depth adjustment on each component model to complete the modeling.

2. A three-dimensional sketch modeling method based on single-view axis manipulation according to claim 1, characterized in that: In step S2, the contour curve is represented by a cubic B-spline curve, which fits the contour line drawn by the user into a closed curve.

3. The three-dimensional sketch modeling method based on single-view axis manipulation according to claim 2, characterized in that: In step S3, the posture axis is displayed on the computer screen after the contour curve is generated, and the user sets the posture axis using an interactive adjustment method.

4. The three-dimensional sketch modeling method based on single-view axis manipulation according to claim 3, characterized in that: In step S4, the generation algorithm is specifically as follows: P Considered as the construction line L of a three-dimensional component C In the attitude axis U xyz Defined xy plane π U Orthogonal projection on the xy plane, from the perpendicular to the xy plane π U The initial three-dimensional model of the part to be modeled is obtained by expanding in the direction of .

5. The three-dimensional sketch modeling method based on single-view axis manipulation according to claim 4, characterized in that: In step S5, since the initial 3D model contour and contour curve L P Incomplete matching, the component optimization algorithm is used to optimize the initial 3D model contour to match the contour curve; the component optimization algorithm is specifically to use the least squares method to minimize E sum : argminE sum =argmin{w1E o +w2E s +w3E F +w4E e } Among them, w1, w2, w3, and w4 are the set weight values; The sub-items are as follows: Where O is the initial three-dimensional model M G The projection contour point set at the current viewing angle is obtained by the Alpha-Shape algorithm; P(·) represents the projection operation; p i Represents the projection contour point P(v i ) corresponding to the contour curve; by minimizing the sub-item E o , so that the projection contour point P(v i ) and its corresponding target point p on the contour curve i The distance between them is the smallest; Among them, n U is the normal of the user-defined attitude axis plane, and d is the plane ∏ U The constant term in the equation, S is M G The set of symmetrical point pairs in the middle, B represents the construction line L C The set of points on ; minimize this sub-item to keep the model relative to the symmetry plane ∏ U symmetry while ensuring that mesh vertices that were originally on the central construction line remain on that line; E F =∑ i ||L(v i )-δ i || 2 , E e =∑ (i,j)∈ε ||v i -v j -η ij || 2 , where L(·) represents the Laplace-Beltrami operator with geometric feature weights, and each vertex v i The target Laplace value calculation formula is δ i =A i c i ·n i , A i is the vertex v i 1-ring area, c i is the target mean curvature, n i is the normal vector at the vertex; e i is the vertex v i The average side length, e j is the vertex v j The average edge length of , ε is the geometry of connected vertices in the mesh; After the component optimization algorithm, the optimized three-dimensional model is obtained.

6. The three-dimensional sketch modeling method based on single-view axis manipulation according to claim 5, characterized in that: In step S6, first, the center construction line and cross-section line of the model are automatically generated. The points on the lines serve as the control points for model deformation. When the user moves these points, the model will deform accordingly. The center construction line point set is directly obtained from the vertex set B on the symmetry plane. When the user uses the center construction line to deform, a deformation point v is selected on the center line of the mesh. b ∈B, and then according to the user's mouse movement on the screen, move the point on the symmetry plane to obtain the constraint point v' b ; The method for generating the control point set of cross-sectional deformation is: perform the coordinate transformation of screen projection, convert the selected point on the screen into the deformation point v s ; The cross-section line is composed of the grid and the plane ∏ S The intersection calculation forms the plane parallel to U xOz Plane and passing through the center of the grid, thus obtaining the point set S; When the user deforms the cross section, the nearest grid point to the point selected from S on the screen is calculated, which is the user's deformation point v s ; After a certain cross-sectional displacement, the constraint point v' is obtained s ; In addition to using the center construction line and the center cross section point set as the control handle editing method, the control handle point set is generated using an arbitrary cross section to achieve deformation; the user selects the vertex v located on the cross section through the center construction line k When using point v k The plane equation of the cross section is generated by the plane normal vector. At the same time, the intersection points of the cross section and the mesh edge are calculated and these intersection points are used as control handles to control the deformation. When the user moves the control handle, the model will deform accordingly. During the deformation process, the model's posture and projection contour remain unchanged. The contour constraint-deformation algorithm is as follows: Among them, w1, w2, w3, and w4 are the set weights, and flag is the symmetry mark. When creating an asymmetric model, flag will be set to 0, and when creating a symmetric model, it will be set to 1; the sub-items are: E F is the smoothing energy term that appeared in step S5; the second term Ensures that the constraint points within the user-defined region of interest are as close as possible to the user-specified position after deformation, v i Indicates the value to be solved, v' i Indicates the deformation position constraint point after user adjustment; E s is the symmetry constraint energy term that appeared in step S5; E o is the contour constraint energy term that appeared in step S5; by minimizing the overall deformation energy term E D , and obtain the deformed component model.

7. The three-dimensional sketch modeling method based on single-view axis manipulation according to claim 6, characterized in that: In step S8, the designed control is used to control the depth of the component model. The depth of each component model is changed by moving the depth control control up and down. The components are interactively combined to finally complete the modeling.

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