Methods and systems for determining cutting planes in 3D model component division, component printing methods, and systems

Abstract

This application discloses a method for determining cutting planes for 3D model component division, a component printing method, and a system, relating to the field of 3D printing technology. The method for determining cutting planes for 3D model component division includes: acquiring surface geometric data of the 3D model to be divided; detecting printing primitives in the surface geometric data, wherein the printing primitives include at least one of an initial substrate, a tip region, and a T-shaped region; determining the cutting plane of the 3D model according to a preset cutting strategy based on the detected printing primitive type; wherein, the 3D model is divided using the cutting plane, and the resulting sub-components have at least one printing substrate. The beneficial effects of this application are: ensuring that 3D model printing adapts to the cutting requirements of different structures and improving cutting accuracy.

Description

Technical Field

[0001] This application relates to the field of 3D printing technology, and in particular to a method for determining the cutting plane for 3D model parts, a part printing method and system. Background Technology

[0002] With the widespread application of 3D printing technology in fields such as large parts, customized sculptures, and industrial prototypes, large-size models must be printed in sections and then assembled due to the size limitations of the 3D printer's forming chamber. Current technologies often rely on manual visual selection of the cutting plane or use automated solutions that involve simple, uniform division and fixed-height translation, resulting in significant problems with the accuracy and adaptability of determining the cutting plane for 3D models.

[0003] Manual cutting relies heavily on operator experience and struggles to adapt to the diverse structural requirements of 3D models. This often results in large areas of overhanging sub-components after segmentation, or a lack of effective printing substrate for proper forming. Automatic segmentation using fixed rules fails to differentiate between geometric features, applying the same cutting logic to irregularly shaped models. This can lead to the truncation of critical features, insufficient wall thickness in sub-components, and cut surfaces too small to accommodate splicing structures. Therefore, improving the accuracy and adaptability of 3D model cutting and printing is a pressing technical challenge in the field of 3D component printing. Summary of the Invention

[0004] This application addresses the problems of poor accuracy and adaptability in the cutting and printing of 3D models in the prior art by providing a method for determining the cutting plane for 3D model parts, a part printing method, and a system. The method for determining the cutting plane for 3D model parts identifies three types of printing primitives: the initial substrate, the tip region, and the T-shaped region. It then matches the corresponding preset cutting strategy to adaptively generate the cutting plane, ensuring that the 3D model printing adapts to the cutting requirements of different structures and improving cutting accuracy.

[0005] To achieve the above technical objectives, this application provides a technical solution: a method for determining cutting planes for three-dimensional model segmentation, comprising: acquiring surface geometric data of the three-dimensional model to be segmented; detecting printing primitives in the surface geometric data, wherein the printing primitives include at least one of an initial base, a tip region, and a T-shaped region; determining the cutting plane of the three-dimensional model according to a preset cutting strategy based on the detected printing primitive type; wherein, the three-dimensional model is segmented using the cutting plane, and the resulting segmented sub-parts contain at least one printing base.

[0006] Furthermore, the detection of printing primitives in the surface geometry data includes: determining the initial substrate of the three-dimensional model according to a preset substrate determination strategy; or, determining the tip region of the three-dimensional model according to a preset tip region extraction method; or, determining the T-shaped region of the three-dimensional model according to a preset T-shaped region recognition method.

[0007] Furthermore, determining the initial basis of the 3D model according to the preset basis determination strategy includes: traversing the outer surface patches of the 3D model, clustering adjacent outer surface patches with the same normal direction into the same planar surface to generate a set of planar surfaces; taking the planar surfaces in the set of planar surfaces that satisfy the preset stability constraints as candidate printing bases; sorting the candidate printing bases according to the preset sorting strategy, and taking the candidate printing base with the highest sorting as the initial basis.

[0008] Furthermore, the preset stability constraint includes: the angle between the normal direction of the planar surface and the vertical direction is less than or equal to a preset angle threshold; and / or, there are no other entities of the three-dimensional model below the planar surface along the vertical direction.

[0009] Furthermore, the preset sorting strategy includes: sorting according to the area of ​​the candidate printing substrates; or, for each candidate printing substrate, generating a uniform random number between 0 and 1, and randomly sorting according to the area of ​​the candidate printing substrate and the uniform random number.

[0010] Furthermore, the step of determining the cutting plane of the 3D model according to the detected printing primitive type and a preset cutting strategy includes: if the printing primitive is the initial base, then the initial base is used as a reference and translated along the extension direction of the 3D model to generate several candidate cutting planes; if a candidate cutting plane generated by a certain translation does not meet the printing conditions, then the candidate cutting plane that meets the printing conditions in the previous translation sequence is taken as the final cutting plane.

[0011] Furthermore, the step of determining the cutting plane of the 3D model according to the detected printing primitive type and a preset cutting strategy includes: if the printing primitive is the initial base, then using the initial base as a reference, gradually translating along the extension direction of the 3D model to generate several candidate cutting planes; if a candidate cutting plane generated by a certain translation does not meet the printing conditions, then the candidate cutting plane that meets the printing conditions in the previous translation sequence is taken as the initial cutting plane; obtaining the center point of the initial cutting plane; determining the next parallel plane along the direction away from the initial base from the initial cutting plane, and obtaining the vertex closest to the initial base in the parallel plane; using the center point as the rotation center, rotating the normal direction of the initial cutting plane toward the vertex, and taking the plane corresponding to the maximum rotation angle as the final cutting plane of the 3D model.

[0012] Furthermore, the step of rotating the normal direction of the initial cutting plane towards the vertex with the center point as the rotation center, and taking the plane corresponding to the maximum rotation angle as the final cutting plane includes: if a cutting abnormality occurs when the 3D model is trial-cut with the plane corresponding to the current maximum rotation angle, then the initial cutting plane is re-rotated by half of the current maximum rotation angle, and the trial cutting and re-rotation are repeated until there is no cutting abnormality or the iteration termination condition is met, and the plane corresponding to the last rotation is taken as the final cutting plane of the 3D model.

[0013] Furthermore, the step of determining the tip region of the three-dimensional model according to the preset tip region extraction method includes: performing voxelization on the three-dimensional model to obtain a voxelized mesh representation; running a multi-scale protrusion structure detection algorithm on the voxelized mesh representation to identify protruding parts in the three-dimensional model, and taking the identified protruding parts as the tip region.

[0014] Furthermore, the step of determining the cutting plane of the three-dimensional model according to the detected printing primitive type and a preset cutting strategy includes: if the printing primitive is a tip region, then identifying the boundary contour between the tip region and the main body of the three-dimensional model, and using the plane that passes through the boundary contour and is perpendicular to the extension direction of the tip region as the final cutting plane of the three-dimensional model.

[0015] Furthermore, the step of determining the cutting plane of the 3D model according to the detected printing primitive type and a preset cutting strategy includes: if the printing primitive is a pointed region, then identifying the boundary contour between the pointed region and the main body of the 3D model, and taking the plane that passes through the boundary contour and is perpendicular to the extension direction of the pointed region as the initial cutting plane; taking the initial cutting plane as a reference, gradually translating in a direction away from the pointed region to generate several candidate cutting planes; if a candidate cutting plane generated by a certain translation does not meet the printing conditions, then taking the previous candidate cutting plane that meets the printing conditions in the translation sequence as the final cutting plane.

[0016] Furthermore, the step of determining the cutting plane of the 3D model according to the detected printing primitive type and a preset cutting strategy includes: if the printing primitive is a pointed region, then the boundary contour between the pointed region and the main body of the 3D model is identified, and the plane passing through the boundary contour and perpendicular to the extension direction of the pointed region is taken as the initial cutting plane; with the initial cutting plane as a reference, the plane is gradually translated in a direction away from the pointed region to generate several candidate cutting planes; if a candidate cutting plane generated by a certain translation does not meet the printing conditions, then the candidate cutting plane is taken as the target plane, and the previous candidate cutting plane that meets the printing conditions is taken as the plane to be rotated; with the center of the plane to be rotated as the rotation center, the normal of the plane to be rotated is rotated toward the target plane by a preset angle to obtain the updated initial cutting plane; the operation of translating to generate candidate cutting planes and updating plane rotation is repeated until the plane angle between the plane to be rotated and the target plane is less than a preset angle threshold, and the last candidate cutting plane that meets the printing conditions is taken as the final cutting plane of the 3D model.

[0017] Furthermore, the step of running a multi-scale protrusion detection algorithm on the voxelized mesh representation to identify protrusions in the 3D model includes: performing convolution operations on the voxelized mesh representation based on several preset binary templates to obtain the local maximum value corresponding to each binary template, and using the voxel position corresponding to the local maximum value as a candidate point for a fine-scale protrusion; clustering the detected candidate points for protrusions, merging candidate points belonging to the same protrusion region, and identifying them as the fine-scale protrusions; and / or, performing scale expansion on the preset binary templates to generate at least one scale expansion template with an expanded receptive field; performing convolution operations on the scale expansion template on the voxelized mesh representation to detect local maximum values, and using the voxel position corresponding to the local maximum value as the large-scale protrusion.

[0018] Furthermore, the step of determining the T-shaped region of the 3D model according to the preset T-shaped region identification method includes: performing voxelization on the 3D model to obtain a voxelized mesh representation; constructing a graph structure using each voxel in the voxelized mesh representation as a vertex and the adjacency relationship between adjacent voxels as edges; in the graph structure, for each vertex, obtaining the set of adjacent vertices within a preset distance around the vertex; detecting the number of connected components in the set of adjacent vertices, and if the number of connected components is greater than or equal to 2, then identifying the vertex as a connected vertex in the T-shaped region, and using the space occupied by the voxels of all connected vertices as the T-shaped region.

[0019] Furthermore, the step of determining the cutting plane of the 3D model according to the detected printing primitive type and a preset cutting strategy includes: if the printing primitive is a T-shaped region, then all connected components of the T-shaped region are obtained; an offset vector is determined based on the centroids of the two sets of connected components; an initial cutting plane is constructed perpendicular to the offset vector and passes through the centroid of the first connected component, and the initial cutting is performed on the 3D model using the initial cutting plane; using the slice generated by the initial cutting as the base plane, it is gradually translated along the direction toward the second connected component to generate several candidate cutting planes; if a candidate cutting plane generated by a certain translation does not meet the printing conditions, then the initial cutting is cancelled, and the candidate cutting plane is used as the final cutting plane of the 3D model; wherein, the width of the first connected component along the T-shaped intersection direction is less than the width of the second connected component along the T-shaped intersection direction.

[0020] Furthermore, when the total number of connected components in the T-shaped region is greater than 2, the connected component with the largest width along the T-shaped intersection direction is selected as the second connected component, and all connected components other than the first connected component are merged as the first connected component.

[0021] Furthermore, on the side containing the first connected component, the cut surface generated by the cutting forms a potential tip region; on the side containing the second connected component, the cut surface generated by the cutting forms a flat surface, which serves as a potential initial substrate for printing.

[0022] Another technical solution provided in this application is a three-dimensional model component printing method, which includes the following steps: based on the three-dimensional model component cutting plane determination method as described above, obtain the cutting plane to cut the three-dimensional model and obtain the cut sub-components; determine the connection method between the cut sub-components based on the cutting plane, generate the connection structure corresponding to each cut sub-component according to the connection structure generation strategy corresponding to the connection method, and form a component sub-component model; and perform printing using the component sub-component model.

[0023] Furthermore, the step of cutting the three-dimensional model based on the cutting plane to obtain the cut sub-components includes: cutting the three-dimensional model based on the cutting plane to divide the three-dimensional model into a first cut sub-component and a second cut sub-component located on both sides of the cutting plane; wherein, the first cut sub-component has at least one first cutting surface formed by the cutting plane, and the second cut sub-component has at least one second cutting surface formed by the cutting plane, and the first cutting surface and the second cutting surface are paired one-to-one.

[0024] Furthermore, after acquiring the cut sub-component, the following steps are performed: calculate the cross-sectional area of ​​the first or second cut surface; if any cross-sectional area is less than a preset cross-sectional area threshold, prompt the user to re-determine the cut surface or that the cut surface position is inappropriate; and / or calculate the remaining height corresponding to each cut surface in the first and second cut sub-components; if the remaining height of all cut surfaces is less than a preset remaining height threshold, prompt the user to re-determine the cut surface or that the cut surface position is inappropriate.

[0025] Furthermore, the connection structure generation strategy includes: generating a protruding structure and a recessed structure that cooperate with each other on the first cutting surface and the second cutting surface, respectively; or generating a recessed structure on both the first cutting surface and the second cutting surface, and generating an independent connector that cooperates with the recessed structure.

[0026] Another technical solution provided in this application is a three-dimensional model component printing system, comprising: a three-dimensional printer for performing the three-dimensional model component printing method as described above.

[0027] The beneficial effects of this application are: 1. By employing a preset cutting strategy, the 3D model is segmented into multiple printer-compatible sub-components. The connection structures for each sub-component are then determined based on the shape of the cut planes. These connection structures, along with the sub-components, form the individual sub-component models for each print run. This improves print adaptability and ensures that each sub-component model, after printing, can form a complete printed structure corresponding to the 3D model through the connection structures. Through the collaborative design of cutting and connection structures, print adaptability is ensured while also considering splicing accuracy and structural strength, thereby improving printing efficiency and finished product quality.

[0028] 2. By first determining the initial substrate and then determining the cutting plane based on the maximum continuous printing area corresponding to the initial substrate, the cutting plane is made to be the optimal cutting position from the initial substrate that can stably print the maximum continuous range. This ensures that the sub-component located on one side of the substrate after cutting has the optimal printing state, so that the cut sub-component can achieve maximum volume printing with the initial substrate as the printing reference, improving the rationality and efficiency of cutting, and reducing the user's operating threshold and professional requirements. Attached Figure Description

[0029] Figure 1 This is a flowchart illustrating the method for determining the cutting planes for the three-dimensional model of this application.

[0030] Figure 2 This is a schematic diagram illustrating the generation of the initial base in the method for determining the cutting plane for the three-dimensional model of this application.

[0031] Figure 3This is a schematic diagram of the three-dimensional model of the three-dimensional model component printing method of this application.

[0032] Figure 4 This is a schematic diagram of the 3D model cutting method for the 3D model component printing method of this application.

[0033] Figure 5 This is a schematic diagram of the protruding structure on the cutting surface in the three-dimensional model component printing method of this application.

[0034] Figure 6 This is a schematic diagram of the recessed structure on the cutting surface in the three-dimensional model component printing method of this application.

[0035] Figure 7 This is a schematic diagram showing the connection between the protruding and recessed structures in the three-dimensional model component printing method of this application. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description of this application is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely one preferred embodiment of this application and are only used to explain this application. They do not limit the scope of protection of this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] like Figure 1 As shown in Embodiment 1 of this application, the method for determining the cutting plane for dividing a three-dimensional model includes: Obtain the surface geometry data of the 3D model to be segmented; Detect printing primitives in surface geometry data, wherein the printing primitives include at least one of an initial substrate, a tip region, and a T-shaped region; Based on the detected type of printing primitive, the cutting plane of the 3D model is determined according to the preset cutting strategy; In this process, the three-dimensional model is divided by a cutting plane, and the resulting cut sub-parts have at least one printing base.

[0038] In this embodiment, by acquiring the surface geometric data of the three-dimensional model to be segmented and detecting different types of printing primitives, the key geometric features of the model are adaptively identified, thereby adopting differentiated preset cutting strategies for different structures. This ensures that no matter how complex the model shape is, each segmented sub-component has a stable base that can be directly supported by the printing platform, ensuring that the cutting results meet the requirements of printing stability and structural integrity.

[0039] In this embodiment, surface geometry data can be obtained by reading a 3D model file. The 3D model file format includes, but is not limited to, STL, OBJ, and AMF formats. The surface geometry data includes at least vertex coordinates, facet normal information, and topological adjacency relationships between faces. The printing substrate refers to a solid planar area that can directly contact the printing platform of the 3D printer and support the entire cutting sub-component for printing.

[0040] Specifically, the printing primitives in the surface geometry data include: The initial basis of the 3D model is determined according to a preset basis determination strategy; or, The tip region of the 3D model is determined according to a preset tip region extraction method; or, The T-shaped region of the 3D model is determined according to the preset T-shaped region recognition method.

[0041] like Figure 2 As shown, determining the initial basis of the 3D model according to the preset basis determination strategy includes: Traverse the outer surface patches of the 3D model, and cluster adjacent outer surface patches with the same normal direction into the same planar surface to generate a set of planar surfaces; Planar surfaces that satisfy the preset stability constraints from the set of planar surfaces are selected as candidate printing substrates; The candidate printing substrates are sorted according to a preset sorting strategy, and the candidate printing substrate with the highest sorting is used as the initial substrate.

[0042] A planar surface that meets the preset stability constraints is used as a candidate printing base. The candidate printing base with the largest area is selected as the initial base by sorting by area. This maximizes the contact area between the base and the printing platform in one printing process, and realizes the independent optimal placement of the model after parting during the printing process, ensuring the reliability and efficiency of printing.

[0043] In this embodiment, the preset stability constraints include the angle between the normal direction of the planar surface and the vertical direction being less than or equal to a preset angle threshold, and / or, the absence of other entities of the 3D model below the planar surface along the vertical direction. The preset angle threshold can be set according to the size of the 3D model. In this embodiment, the preset angle threshold is 10° to 20°, with a default value of 15°. The larger the size of the 3D model, the more relaxed the preset angle threshold can be.

[0044] Among them, planar surfaces can be obtained using breadth-first search.

[0045] Preset sorting strategies include: Sort by area; or, For each candidate printing substrate, generate a uniform random number between 0 and 1, and then randomly sort the candidates based on their area and the uniform random number.

[0046] In the preset sorting strategy that sorts by area, the candidate printing base with the largest area is used as the initial base.

[0047] In the preset sorting strategy for random sorting, several random sorting results are generated, and the candidate printing basis that ranks first (i.e., the largest ranking) in each sorting result is used as the initial basis. Random variables are introduced into the area sorting of the candidate printing basis to expand the explorable candidate space, avoid suboptimal basis that may be caused by a single sorting result, and improve the adaptability of the initial basis.

[0048] In the first case where the printing primitive is the initial base, the cutting plane of the 3D model is determined according to a preset cutting strategy based on the initial base, including the following steps: Using the initial base as a reference, translate along the extension direction of the 3D model to generate several candidate cutting planes; If a candidate cutting plane generated by a certain translation does not meet the printing conditions, then the candidate cutting plane that meets the printing conditions in the previous translation sequence will be taken as the final cutting plane.

[0049] Printing conditions must include at least meeting wall thickness requirements, complying with overhang regulations, having a stable base, and ensuring the structure is not easily deformed. Specifically, the minimum printing wall thickness, self-supporting critical angle, and minimum initial base area can be set for the equipment. When a candidate cutting plane does not meet the printing conditions, it is considered a non-printable surface; when a candidate cutting plane meets the printing conditions, it is considered a printable surface. The preceding printable surface of the non-printable surface is used as the initial cutting plane to achieve maximum volume extraction under printability constraints.

[0050] In the second case where the printing primitive is the initial base, the cutting plane of the 3D model is determined according to a preset cutting strategy based on the initial base, including the following steps: Using the initial base as a reference, the model is gradually translated along the extension direction of the three-dimensional model to generate several candidate cutting planes. If a candidate cutting plane generated by a certain translation does not meet the printing conditions, then the candidate cutting plane that meets the printing conditions in the previous translation sequence will be used as the initial cutting plane. Obtain the center point of the initial cutting plane; Determine the next parallel plane along the direction away from the initial base from the initial cutting plane, and obtain the vertex in that parallel plane that is closest to the initial base; Using the center point as the center of rotation, rotate the normal direction of the initial cutting plane toward the vertex, and use the plane corresponding to the maximum rotation angle as the final cutting plane of the 3D model.

[0051] In this embodiment, by obtaining the center point of the initial cutting plane and the vertex closest to the initial base in the next parallel plane, and rotating the normal direction of the cutting plane towards the side where the vertex is located by a preset angle with the center point as the rotation center, adaptive attitude fine-tuning of the cutting plane in three-dimensional space is achieved. The vertex represents the most prominent point on the obstacle surface or overhang surface where printing is first impossible when printing from the base direction. Rotating the normal direction of the initial cutting plane towards the vertex is equivalent to adjusting the cutting plane from a state completely parallel to the base to a slightly tilted state. This allows the cutting plane to avoid the obstacle area that would originally hinder printing in space, thereby transforming the originally unprintable part into a printable part without sacrificing the maximization of volume, further expanding the effective printing range.

[0052] Understandably, the preset angle can be set based on the forming accuracy of the 3D printing equipment and the material properties. In this case, the preset angle is the maximum rotation angle calculated based on the shape of the 3D model. That is, with the center point of the initial cutting plane as the rotation center, when the plane normal is deflected towards the nearest vertex to the base on the parallel plane away from the base, the limit angle that can be deflected without the geometric constraints of model self-intersection, truncation of key structure of the model, or the cutting plane penetrating the boundary of the model entity.

[0053] The process of rotating the initial cutting plane with the center point as the center of rotation and rotating it towards the vertex, with the plane corresponding to the maximum rotation angle as the final cutting plane, includes: If a cutting anomaly occurs when the 3D model is cut using the plane corresponding to the current maximum rotation angle, the initial cutting plane is re-rotated by half of the current maximum rotation angle. This process of trial cutting and re-rotation is repeated until no cutting anomalies are found or the iteration termination condition is met. The plane corresponding to the last rotation is then taken as the final cutting plane of the 3D model.

[0054] A binary search strategy is used to approximate the optimal rotation angle, avoiding the cutting failure that may be caused by directly taking the maximum angle. At the same time, compared with traversing all possible angles, binary iteration can quickly converge to a tilt angle that satisfies both the cutting validity and the largest possible angle, balancing computational efficiency and cutting quality.

[0055] In this embodiment, determining the tip region of the 3D model according to the preset tip region extraction method includes: The 3D model is voxelized to obtain a voxelized mesh representation; A multi-scale protrusion detection algorithm is run on the voxelized mesh representation to identify protrusions in the 3D model and to identify the protrusions as the tip regions.

[0056] Among them, a multi-scale protrusion detection algorithm is run on a voxelized mesh representation to identify protrusions in the 3D model, including: Convolution operation is performed on the voxelized mesh representation based on several preset binary templates to obtain the local maximum value corresponding to each binary template, and the voxel position corresponding to the local maximum value is used as a candidate point for convexity at a fine scale. Clustering the detected candidate protrusions, merging candidate protrusions belonging to the same protrusion region, and identifying them as the fine-scale protrusion portions; and / or, The preset binary template is scaled up to generate at least one scaled-up template with an expanded receptive field. The scale-expanded template is convolved on the voxelized mesh representation to detect local maxima, and the voxel position corresponding to the local maxima is used as the large-scale convex part.

[0057] In this embodiment, the preset binary template consists of 26 3x3x3 binary templates. In the preset binary template, the central voxel and another voxel are set to 1, and the rest are 0. The scale-expanded template is a binary template formed by inserting 21 zeros at the first level between each pair of values ​​in the preset binary template.

[0058] The sum of the number of target voxels in the preset binary template and the response values ​​formed by the empty positions in the template except for the central voxel is zero, so that the convolution result of the preset binary template and the scale-extended template in the constant region of the voxelized mesh representation is zero, and a non-zero response is only generated at the boundary of the 3D model.

[0059] In the first case, where the printing primitive is a pointed region, the cutting plane of the 3D model is determined by the pointed region and a preset cutting strategy, including: Identify the boundary contour between the tip region and the main body of the 3D model, and use the plane that passes through the boundary contour and is perpendicular to the extension direction of the tip region as the final cutting plane of the 3D model.

[0060] In this case, the junction between the tip region and the main body is used as the cutting plane, so that the tip sub-component is completely cut off after cutting without losing the structural integrity of the main body, thus ensuring the accuracy of feature segmentation.

[0061] In the second case, where the printing primitive is a pointed region, the cutting plane of the 3D model is determined by the pointed region and a preset cutting strategy, including: Identify the boundary contour between the tip region and the main body of the 3D model, and use the plane that passes through the boundary contour and is perpendicular to the extension direction of the tip region as the initial cutting plane; Using the initial cutting plane as a reference, the plane is gradually translated along a direction away from the tip region to generate several candidate cutting planes; If a candidate cutting plane generated by a certain translation does not meet the printing conditions, then the candidate cutting plane that meets the printing conditions in the previous translation sequence will be taken as the final cutting plane.

[0062] By shifting the cutting surface from the tip root towards the interior of the main body, additional solid material thickness is reserved for the cutting sub-components in the tip area. This avoids the problems of excessively thin walls, fragile structures, or easy breakage during printing that would result from cutting directly at the root, thus improving the structural strength and printing reliability of the cutting sub-components in the tip area.

[0063] In the third case, where the printing primitive is a pointed region, the cutting plane of the 3D model is determined by the pointed region and a preset cutting strategy, including: If the printed primitive is a pointed area, the boundary contour between the pointed area and the main body of the 3D model is identified, and the plane that passes through the boundary contour and is perpendicular to the extension direction of the pointed area is used as the initial cutting plane. Using the initial cutting plane as a reference, the plane is gradually translated along a direction away from the tip region to generate several candidate cutting planes; If a candidate cutting plane generated by a certain translation does not meet the printing conditions, then the candidate cutting plane is taken as the target plane, and the previous candidate cutting plane that meets the printing conditions is taken as the plane to be rotated. Using the center of the plane to be rotated as the rotation center, rotate the normal of the plane to be rotated toward the target plane by a preset angle to obtain the updated initial cutting plane; Repeat the translation to generate candidate cutting planes and plane rotation to update the planes until the angle between the plane to be rotated and the target plane is less than a preset angle threshold. The last candidate cutting plane that meets the printing conditions is taken as the final cutting plane of the 3D model.

[0064] In this scenario, alternating translation and rotation iterations ensure that each cut sub-part meets printing requirements after cutting, continuously approaching the optimal tilt cutting posture. This allows the cutting plane to separate the tip from the main body at the best angle, providing sufficient thickness for the tip area while maximizing the preservation of the main body's volume, and avoiding the blindness of a single fixed angle adjustment. In this embodiment, the preset angle ranges from 5° to 12°, with a default of 8°, and a preset angle threshold of 3°. In other embodiments, the preset angle can also be set according to the 3D model size and tip detail requirements, the 3D printing process type, and the 3D model voxels. The preset angle threshold can be set according to printing accuracy requirements and cutting plane assembly accuracy requirements. It is understood that if the number of times the translation to generate candidate cutting planes and the plane rotation to update are repeated reaches the preset iteration threshold, iteration stops, and the last candidate cutting plane that meets the printing requirements is taken as the final cutting plane of the 3D model. The preset iteration threshold can be set to 10.

[0065] If the initial cutting plane obtained after rotation already has a cut sub-part that cannot be printed when cutting the 3D model, the operation of translating to generate candidate cutting planes and updating the plane by rotation is also terminated, and the previous printable surface is used as the final cutting plane of the 3D model.

[0066] In this embodiment, determining the T-shaped region of the 3D model according to the preset T-shaped region recognition method includes: The 3D model is voxelized to obtain a voxelized mesh representation; A graph structure is constructed using each voxel in the voxelized mesh representation as a vertex and the adjacency relationship between adjacent voxels as an edge. In a graph structure, for each vertex, obtain the set of neighboring vertices within a preset distance around that vertex; The number of connected components in the set of adjacent vertices is detected. If the number of connected components is greater than or equal to 2, the vertex is identified as a connected vertex in the T-shaped region. The space occupied by the voxels of all connected vertices is taken as the T-shaped region.

[0067] In a T-shaped structure, voxels around the central vertex are spatially distributed in three different directions: the top and bottom of the trunk, and the lateral extension of the branches. These voxels only intersect at the central vertex and are not directly adjacent to each other. Therefore, when the number of detected connected components is greater than or equal to 2, a T-shaped connection is identified at that location. By merging the spatial regions occupied by all the marked connected vertices, the complete T-shaped region can be obtained.

[0068] In this design, the closed surface enclosed by the outermost voxel surface among all connected vertices serves as the boundary of the T-shaped region. The preset distance is a threshold number of voxel layers extending outward along the three-dimensional coordinate axis, centered on a single voxel vertex. In this embodiment, the preset distance is 1 to 3 voxel units, with a default of 2 voxel units. In other embodiments, the preset distance can be adaptively set according to the voxel mesh resolution and the thickness of the T-shaped branches.

[0069] By utilizing connected component analysis in graph theory, the central hub position where different branches intersect in a T-shaped structure can be identified. Even if the branch directions are complex or the thickness is uneven, it can be accurately captured through voxel adjacency relationships, avoiding misjudgments that may occur if relying solely on geometric rules, and improving the accuracy of T-shaped region identification.

[0070] Determining the cutting plane of the 3D model based on the T-shaped region and a preset cutting strategy includes: Obtain all connected components of the T-shaped region; The offset vector is determined based on the centroids of the two connected components; Construct an initial cutting plane that is perpendicular to the offset vector and passes through the centroid of the first connected component, and perform an initial cut on the 3D model using the initial cutting plane; Using the slice generated from the initial cut as the base plane, gradually translate along the direction toward the second connected component to generate several candidate cutting planes; If a candidate cutting plane generated by a translation does not meet the printing conditions, the initial cutting is cancelled, and the candidate cutting plane is used as the final cutting plane of the 3D model. The width of the first connected component along the T-shaped intersection direction is smaller than the width of the second connected component along the T-shaped intersection direction.

[0071] By first cutting along the centroid line perpendicularly, and then gradually translating the slice to separate the mutually perpendicular or intersecting branches in the T-shaped region, the optimal cutting position is finally found that can completely separate each branch and ensure that each sub-component has a stable base. This avoids the problem of geometric residues or branches that cannot be printed independently that may be caused by a single cutting plane.

[0072] In this embodiment, the first connected component is a narrower connected component, and the second connected component is a wider connected component. An initial cutting plane is constructed that is perpendicular to the offset vector and passes through the centroid of the narrower connected component. An initial cut is performed on the 3D model using the initial cutting plane. The slice generated by the initial cut is used as the base plane, and the model is gradually translated along the direction toward the wider connected component to generate several candidate cutting planes.

[0073] At this point, using the centroid of the narrower connected component as the starting point for retrieval and searching towards the wider connected component, the critical plane of the forming defect in the thin-walled region is identified. After dividing the three-dimensional model with this critical plane, the large-area thin-walled main body is independently divided into a single cut sub-part, and the thickened local area is separated separately to avoid deformation caused by the simultaneous existence of thin-walled and thick-walled structures in the same part, thus protecting the integrity of the thin-walled structure printing.

[0074] When the total number of connected components in the T-shaped region is equal to 2, the two connected components are divided into a first connected component and a second connected component according to their width along the T-shaped intersection direction. That is, the connected component with the larger width along the T-shaped intersection direction is the second connected component, i.e., the wider connected component, and the connected component with the smaller width along the T-shaped intersection direction is the first connected component, i.e., the narrower connected component.

[0075] When the total number of connected components in the T-shaped region is greater than 2, the connected component with the largest width along the intersection direction of the T-shape is selected as the second connected component, i.e., the wider connected component. All connected components other than the second connected component are merged as the first connected component, i.e., the narrower connected component.

[0076] When the number of connected components is greater than 2, the connected component with the largest width along the T-shaped intersection direction is taken as the wider connected component, and the remaining connected components are merged into the narrower connected component. This ensures that regardless of how many branches the T-shaped region contains, it can be uniformly reduced to two geometric entities. Furthermore, a plane perpendicular to the offset vector and passing through the centroid of the first connected component, i.e., the narrower connected component, is used as the cutting plane. This ensures that the cutting plane can completely separate the narrow side from the T-shaped structure, ensuring the geometric integrity and fitting accuracy of the two sub-components at the interface.

[0077] Specifically, all connected components except the one with the largest volume or the largest width along the intersection direction are logically merged in voxel space and treated as a whole. The merged whole is taken as the narrower connected component, and its centroid is the geometric center of the merged whole.

[0078] In this process, on the side containing the first connected component, the cut surface formed by the cutting creates a flat surface, which serves as a potential initial substrate for printing; on the side containing the second connected component, the cut surface formed a potential tip region.

[0079] By pre-determining potential initial substrates and potential tip regions, the repetitive operations of subsequent potential tip region generation and substrate construction are reduced, thereby improving printing efficiency.

[0080] like Figure 3 , Figure 4 As shown in Embodiment 2 of this application, the three-dimensional model component printing method includes the following steps: Using any of the three-dimensional model component division methods in Example 1, the cutting plane is obtained to cut the three-dimensional model and obtain the cut sub-components. Based on the cutting plane, the connection method between the cut sub-components is determined, and the connection structure corresponding to each cut sub-component is generated according to the connection structure generation strategy corresponding to the connection method, thus forming a sub-component model. Print using the component model.

[0081] In this embodiment, the 3D model is segmented using a preset cutting strategy, breaking it down into multiple printer-compatible sub-components. The connection structures corresponding to different sub-components are then determined based on the shape of the cut planes. These connection structures and the sub-components together form the individual sub-component models for each print run. This improves print adaptability and ensures that each sub-component model, after printing, can form a complete printed structure corresponding to the 3D model through the connection structures. Through the collaborative design of cutting and connection structures, print adaptability is ensured while also considering splicing accuracy and structural strength, thereby improving the printing efficiency and finished product quality of the 3D model.

[0082] In some cases, the cutting plane can also be determined based on the planar parameters entered by the user on the interactive interface.

[0083] In this scenario, the user is prompted to select a cutting plane for the 3D model via an interactive interface. The interface includes functions for translating and rotating the 3D model, facilitating the selection of cutting planes for different regions. The plane parameters must include at least the normal position and spatial position of the cutting plane.

[0084] After determining the cutting planes of the 3D model, execute: Determine if the 3D model is a closed manifold; if not, prompt the user on the interactive interface to repair the 3D model or perform automatic repair according to the model repair strategy; and / or, Determine whether the currently determined cutting plane intersects with the 3D model. If not, prompt the user to re-determine the cutting plane or that the cutting plane position is inappropriate.

[0085] By using closed manifold criteria, the system ensures that the 3D model has a complete volume definition, preventing defects such as broken surfaces, non-manifold edges, or holes from causing the cutting algorithm to fail to correctly calculate the cross-sectional contour or generate incorrect cutting results. When the model does not meet the closed manifold condition, the system prompts the user through the interactive interface to manually repair or execute an automatic repair procedure. Furthermore, if the cutting plane does not actually overlap with the model, the cutting action will not produce effective sub-part segmentation. The system proactively detects this and prompts the user to reselect the cutting plane position, avoiding cutting failures caused by user errors or incorrect plane positioning, thus reducing the time cost of invalid calculations and repeated attempts.

[0086] Understandably, any existing 3D model repair strategy can be used.

[0087] The 3D model is cut based on the cutting plane to obtain the cut sub-components, including: The 3D model is cut based on the cutting plane, dividing the 3D model into a first cutting sub-part and a second cutting sub-part located on both sides of the cutting plane; The first cutting sub-component has at least one first cutting surface formed by cutting with a cutting plane, and the second cutting sub-component has at least one second cutting surface formed by cutting with a cutting plane, with the first cutting surface and the second cutting surface paired one-to-one.

[0088] In this embodiment, if there are multiple cutting planes, each cutting plane corresponds to a combination of a first cutting sub-component and a second cutting sub-component. Depending on the geometry of the three-dimensional model, there may be more than one component in both the first and second cutting sub-components. In this case, there may also be multiple first and second cutting surfaces, but there is a one-to-one correspondence between the first and second cutting surfaces.

[0089] In the first case, the following is executed after obtaining the cut sub-parts: Calculate the cross-sectional area of ​​the first or second cutting surface. If the cross-sectional area of ​​either surface is less than the preset cross-sectional area threshold, prompt the user to re-determine the cutting plane or that the cutting plane position is inappropriate.

[0090] Since the first and second cutting surfaces correspond one-to-one, and the cross-sectional areas of the corresponding first and second cutting surfaces are equal, it is only necessary to calculate any one of the corresponding cutting surfaces.

[0091] In this case, the preset cross-sectional area threshold is set based on the maximum area required for all connection structures. For example, the maximum area required for a single connection structure is 50. The preset cross-sectional area threshold is set to 60. This ensures that any connection structure can be set on any cutting surface. If the cross-sectional area of ​​any cutting surface is greater than or equal to the preset cross-sectional area, then the connection structure is generated. In practical applications, the preset cross-sectional area threshold can be obtained by summing the area required for the solid wall thickness, the area occupied by the process structure, and the maximum area required for setting a single connection structure in the connection structure.

[0092] In the second case, the following is executed after obtaining the cut sub-parts: Calculate the remaining height corresponding to each cutting surface in the first and second cutting sub-components. If the remaining height of all cutting surfaces is less than the preset remaining height threshold, prompt the user to re-determine the cutting plane or the cutting plane position is inappropriate.

[0093] In this case, the calculation process for the remaining height is as follows: The direction perpendicular to the cutting plane is taken as the normal. The farthest normal distance from the first cutting surface to the first cutting sub-component is taken as the remaining height of the first cutting surface; The furthest normal distance from the second cutting surface to the second cutting sub-component is taken as the remaining height of the second cutting surface.

[0094] This refers to the distance between the point furthest from the surface along the normal to each fully connected surface. Using this furthest normal distance, the thickness of each cut sub-component along the cutting direction is quantitatively characterized, reflecting the extent of material extension behind the cut surface in the normal direction, i.e., the material sufficiency of the cut sub-component near the cut surface. Connection structure generation is only performed when all remaining heights are greater than or equal to a preset remaining height threshold, avoiding the placement of connection structures in excessively thin areas and ensuring the reliability of the connection.

[0095] In any of the embodiments of this invention, the preset remaining height threshold is the minimum allowable solid thickness threshold value for the cutting surface to extend into the sub-component solid along its own normal direction. It can be set according to the minimum allowable wall thickness, or it can be set according to the size of the connecting structure, the minimum wall thickness requirement of the printing process, etc. For example, the preset remaining height threshold can be the sum of the depth of the connecting structure along the normal direction and the back safety solid wall thickness allowance.

[0096] In the third case, the following is executed after obtaining the cut sub-parts: Calculate the cross-sectional area of ​​the first or second cutting surface. If the cross-sectional area of ​​any surface is less than the preset cross-sectional area threshold, prompt the user to re-determine the cutting plane or the cutting plane position is inappropriate. Calculate the remaining height corresponding to each cutting surface in the first and second cutting sub-components. If the remaining height of all cutting surfaces is less than the preset remaining height threshold, prompt the user to re-determine the cutting plane or the cutting plane position is inappropriate.

[0097] At this time, the cross-sectional area and remaining height of the cut surface are calculated simultaneously, and a prompt is given if either one is not satisfied.

[0098] like Figure 5 , Figure 6 , Figure 7 As shown, the connection structure generation strategy includes: A matching protruding structure and a recessed structure are respectively generated on the first cutting surface and the second cutting surface; or Recessed structures are generated on both the first and second cutting surfaces, and independent connectors that mate with the recessed structures are generated.

[0099] In this embodiment, instead of calculating and comparing the cross-sectional area and / or remaining height of the cut surfaces after obtaining the cut sub-components, the calculation of the cross-sectional area and / or remaining height of the cut surfaces can be performed after the connection method is determined, based on the connection structure generation strategy corresponding to the connection method. Then, a preset cross-sectional area threshold and a preset remaining height threshold are set according to the connection structure corresponding to the connection structure generation strategy, ensuring that the cross-sectional area and remaining height of each cut surface meet the requirements of the generated connection structure, thus ensuring the accuracy of the prompts. In practical applications, the preset cross-sectional area threshold can be obtained based on the sum of the required wall thickness margin area, the area occupied by the process structure, and the area of ​​the connection structure corresponding to the connection structure generation strategy.

[0100] In the strategy for generating connection structures that produce protruding and recessed structures, there are three ways to generate protruding and recessed structures.

[0101] In the first generation method, the protruding structure consists of several protruding cylinders, each separated by a preset distance, and the recessed structure consists of recessed cylinders that match the position and size of the protruding cylinders.

[0102] At this point, the cut surface is divided into several grids at fixed intervals, and the protruding or recessed cylinders are positioned at the grid intersections. The preset distance is the straight-line distance between the center points of adjacent protruding cylinders within the two-dimensional plane of the cut surface. In this embodiment, the preset distance is between 5mm and 12mm, with a default of 8mm. In other embodiments, the preset distance can be set according to the cross-sectional area of ​​the cut surface, the diameter of the protruding cylinders, the 3D printing process type, and the 3D printing tolerance.

[0103] Understandably, you can first set either a protruding cylinder or a recessed cylinder, and then set the other cylinder according to its position. Alternatively, you can set both protruding and recessed cylinders simultaneously, in which case you must ensure that the mesh division starting points of the two cutting surfaces are the same.

[0104] In a further embodiment of this method, along the mating direction of the protruding cylinder and the recessed cylinder, the protruding cylinder and / or the recessed cylinder have a first section and a second section, in which the protruding cylinder and the recessed cylinder have different mating tightness.

[0105] Optionally, in the first section, the protruding cylinder and the recessed cylinder have a positive clearance fit, and in the second section, the protruding cylinder and the recessed cylinder have a negative clearance fit.

[0106] The mating direction is the direction in which the protruding cylinder is inserted into the recessed cylinder. By setting a difference in diameter between the protruding cylinder and / or the recessed cylinder along the mating direction, the protruding cylinder and the recessed cylinder can be loosely fitted at the opening of the recessed cylinder and tightly fitted at the bottom of the recessed cylinder after mating, thus balancing assembly convenience and connection reliability.

[0107] In the second generation method, the protruding structure consists of several protruding cylinders, each separated by a preset distance. Hollow cylindrical regions are constructed based on the relative positions of the protruding cylinders and a preset wall thickness. The largest cylindrical region between adjacent hollow cylindrical regions is obtained. Using the hollow cylindrical regions and the largest cylindrical region as reserved areas, the areas on the cutting surface other than the reserved areas are hollowed out to form a recessed structure.

[0108] In this method, the hollow cylindrical region is constructed based on the position of the protruding cylinder and the preset wall thickness, retaining a continuous solid hole wall sufficient to enclose the protruding cylinder. This ensures that the hole wall has sufficient bearing area and shear strength during the insertion and mating process, preventing crushing or breakage due to insufficient wall thickness. The largest cylindrical region between adjacent hollow cylindrical regions acts as a solid connecting bridge, linking the independent hole walls together to form a continuous load-bearing skeleton network, avoiding structural weakening caused by localized hollowing. Furthermore, by hollowing out the remaining areas besides the aforementioned retained areas, redundant solid material that does not participate in load-bearing and mating is reduced. This achieves a lightweight design of the recessed structure while maintaining the structural integrity of the connecting areas, reducing printing material consumption and printing time, and lightening the overall weight of the final assembled part. In this case, the preset distance setting is the same as in the first generation method.

[0109] It is understandable that hollowing out refers to hollowing out the sub-component's outer shell structure, hollow cylindrical area structure, and largest cylindrical area structure while retaining the original structure.

[0110] In the third generation method, the protruding structure includes several protruding buckles, and the recessed structure is a recessed cylinder or groove that matches each buckle.

[0111] Specifically, the corresponding protruding and recessed structures generated on the first and second cutting surfaces include: For the corresponding first and second cutting surfaces, compare their remaining heights; If the remaining height of the first cut surface is greater than the remaining height of the second cut surface, a recessed structure is generated on the first cut surface and a protruding structure is generated on the second cut surface. If the remaining height of the first cut surface is less than the remaining height of the second cut surface, a protruding structure is generated on the first cut surface and a recessed structure is generated on the second cut surface.

[0112] By comparing the remaining height of paired cut surfaces to determine the allocation of protruding and recessed structures, the connection structure generation strategy achieves adaptive adaptation to the local wall thickness of segmented sub-components, avoiding the process risks of parts being punctured or having insufficient wall thickness due to excessively deep drilling. Simultaneously, each pair of cut surfaces is compared and allocated independently, allowing different cut surfaces on the same segmented sub-component to obtain different protruding and recessed structure allocation results based on their respective remaining heights. This adapts to the actual situation of uneven thickness distribution at different spatial locations in complex models, eliminating the need for manual judgment and adjustment, thus balancing part division efficiency and accuracy.

[0113] In a connection structure generation strategy that generates recessed structures and independent connectors, there are three ways to generate recessed structures and independent connectors.

[0114] In the first generation method, several recessed structures are provided on both the first and second cutting surfaces. The recessed structures are recessed cylinders, and the independent connectors are columnar connectors adapted to the recessed cylinders. They are used to insert into the corresponding recessed cylinders on the first and second cutting surfaces to realize the connection between the first cutting sub-component and the second cutting sub-component.

[0115] In the second generation method, several recessed structures are provided on both the first and second cutting surfaces. The independent connecting parts are several clips with radial elastic expansion and contraction at their ends. The recessed structure is a recessed cylinder adapted to the clip. The clip is configured to undergo radial elastic deformation when inserted into the recessed cylinder, forming a locking engagement with the recessed cylinder. The two ends of the stud are threadedly engaged with the internal threaded holes on the first and second cutting surfaces, respectively, to achieve the connection between the first cutting sub-component and the second cutting sub-component.

[0116] In the third generation method, several recessed structures are provided on both the first and second cutting surfaces. The independent connecting parts are studs, and the recessed structures are internal threaded holes that mate with them. The two ends of the studs are threadedly engaged with the internal threaded holes on the first and second cutting surfaces, respectively, to realize the connection between the first cutting sub-component and the second cutting sub-component.

[0117] In this embodiment, for two cut surfaces caused by the same cutting plane, any method can be selected to generate the connection structure as required.

[0118] After generating the connection structure, the following is also included: Perform trimming operations on the outer contours of the first and / or second cut surfaces; and / or, Perform a material thickening operation at the root of the protruding structure.

[0119] In this embodiment, a trimming operation is performed on the outer contour of the cut surface to eliminate sharp edges and corners caused by planar cutting, compensating for fit deviations caused by surface roughness or dimensional errors in the 3D printed parts. Secondly, by performing a material thickening operation on the root of the protruding structure, a solid base thickening layer is generated at the connection between the protruding structure and the main body of the cut sub-component. This increases the contact area and load-bearing cross-sectional area between the root and the main body, transforming the originally weak line contact or small-area connection into a surface contact and a large-size transition connection. This disperses the bending and tensile stresses borne by the root during assembly, preventing root fracture or interlayer delamination due to stress concentration, and improving the durability and structural reliability of the protruding structure during repeated insertion and removal and use.

[0120] Specifically, performing trimming operations on the outer contours of the first and / or second cut surfaces includes: Generate a template outline that is offset outward along the outer contour, extrude the template outline along the normal direction of the cutting surface to form a template solid, and perform Boolean operation between the template solid and the original geometry of the cut sub-parts to form a chamfered transition surface at the outer contour. And / or, Generate a template outline that indents inward along the outer contour. Extrude the template outline along the normal direction of the cutting surface to form a template solid. Perform Boolean operations on the template solid and the original geometry of the cut sub-parts to reduce the overall outer contour inward by a preset size.

[0121] In forming the chamfered transition surface, the template profile is generated by offsetting the outer contour line of the cutting surface outward by a preset distance along the cutting surface plane. This offset operation makes the template profile larger than the original outer contour in the horizontal direction. After the offset template profile is extruded along the normal direction of the cutting surface to form a three-dimensional template entity, its inner sidewall is located outside the original outer contour. That is, the template entity covers the outer edge area of ​​the original cut sub-component in the horizontal direction, and extends from the cutting surface to a preset height in the vertical direction. When the template entity performs a Boolean difference operation with the original geometry, since the template entity has the largest coverage area at the cutting surface and the coverage area gradually decreases to zero away from the cutting surface, the amount of material removed at the edge of the original cut sub-component shows a distribution characteristic of the most material removed at the cutting surface and decreasing away from the cutting surface. The removal boundary forms an inclined transition surface extending from the cutting surface into the cut sub-component, that is, the chamfered transition surface. The chamfered transition surface allows the protruding structure to automatically slide into the corresponding position of the recessed structure along the chamfered surface during assembly, even with slight angular deviations or alignment errors. This reduces the user's alignment accuracy requirements and initial insertion resistance. The preset distance is the vertical distance by which the original outer contour line of the cutting surface is uniformly shifted away from the part entity within the two-dimensional plane of the cutting surface. In this embodiment, the preset distance is 1mm to 2mm, with a default of 1.5mm. In other embodiments, this distance can be set according to 3D printing tolerances, component assembly accuracy requirements, etc.

[0122] In the process of reducing the overall outer contour inward by a preset size, the template contour is generated by indenting the outer contour line of the cutting surface inward by a preset distance along the cutting surface plane. This indentation operation makes the template contour smaller than the original outer contour in the horizontal direction, meaning the template contour is completely inside the cutting surface. After the indented template contour is extruded along the normal direction of the cutting surface to form a three-dimensional template entity, its outer wall is located inside the original outer contour, meaning the template entity completely covers a ring area inside the edge of the cutting surface. When the template entity performs a Boolean difference operation with the original geometry, the material inside the edge of the cutting surface is removed, while the material outside the edge of the cutting surface is retained. After removal, the outer contour of the cutting surface is no longer retained in its original position, but is reduced inward by a preset distance, forming a clearance space or step at the outer edge of the cutting surface to eliminate possible interference and collisions between the outer edge of the cutting surface and the corresponding positions of the cut sub-components. This ensures that the outer contour edges of the two cut sub-components will not interfere with each other due to dimensional deviations or printing errors when they approach each other. The preset distance is the distance by which the original outer contour line of the cutting surface is translated vertically inward towards the interior of the model entity, with the plane where the cutting surface is located as the reference. In this embodiment, the preset distance is between 0.5mm and 1.5mm, with a default value of 1mm. In other embodiments, the distance can be set according to the tolerance of 3D printing, the precision requirements of component assembly, etc.

[0123] Performing material thickening operations at the root of protruding structures includes: The protruding structure is translated outward by a predetermined distance along its growth direction, and a solid base thickening layer is generated at the root of the protruding structure by utilizing the spatial gap generated by the translation through Boolean operations.

[0124] The preset distance is the unidirectional distance by which the protrusion is shifted along its outward growth direction. The preset distance is 2 millimeters. By adding a continuous solid base to the bottom of the protrusion, the load-bearing cross-sectional area at the connection between the root and the main body is increased.

[0125] In this embodiment, after generating the connection structure, sub-component models are formed. Multiple sub-component models are then assigned to different printheads of a multi-nozzle 3D printer, or to multiple 3D printers, to perform parallel printing tasks. If an independent connector is generated, it is treated as a single sub-component model.

[0126] As a third embodiment of this application, the three-dimensional model component printing system includes: A 3D printer has multiple printheads, a printing base plate, and a drive assembly, which drives the multiple printheads to move independently.

[0127] The 3D printer performs the component printing operation in any of the above embodiments or combinations thereof.

[0128] In some embodiments, there are multiple 3D printers, and different 3D printers print different sub-component models after being divided into parts using a 3D model part-by-part printing method.

[0129] The above-described specific embodiments are preferred embodiments of the method for determining cutting planes, the method for printing parts, and the system for dividing three-dimensional models into parts in this application. They are not intended to limit the specific scope of this application. The scope of this application includes, but is not limited to, these specific embodiments. All equivalent changes made in accordance with the shape and structure of this application are within the protection scope of this application.

Claims

1. A method for determining the cutting planes for component division in a three-dimensional model, characterized in that, include: Obtain the surface geometry data of the 3D model to be segmented; Detect printing primitives in the surface geometry data, wherein the printing primitives include at least one of an initial substrate, a tip region, and a T-shaped region; Based on the detected type of printing primitive, the cutting plane of the 3D model is determined according to the preset cutting strategy; The three-dimensional model is divided by the cutting plane, and the resulting cut sub-components have at least one printing base.

2. The method for determining the cutting plane for three-dimensional model component division as described in claim 1, characterized in that, The detection of printed primitives in the surface geometry data includes: The initial basis of the 3D model is determined according to a preset basis determination strategy; or, The tip region of the 3D model is determined according to a preset tip region extraction method; or, The T-shaped region of the 3D model is determined according to the preset T-shaped region recognition method.

3. The method for determining the cutting plane for three-dimensional model component division as described in claim 2, characterized in that, The process of determining the initial basis of the 3D model according to the preset basis determination strategy includes: Traverse the outer surface patches of the 3D model, and cluster adjacent outer surface patches with the same normal direction into the same planar surface to generate a set of planar surfaces; Planar surfaces that satisfy the preset stability constraints from the set of planar surfaces are selected as candidate printing substrates; The candidate printing substrates are sorted according to a preset sorting strategy, and the candidate printing substrate with the highest sorting is used as the initial substrate.

4. The method for determining the cutting plane for three-dimensional model component division as described in claim 3, characterized in that, The preset stability constraints include: The angle between the normal direction of the planar surface and the vertical direction is less than or equal to a preset angle threshold; and / or, there are no other entities of the three-dimensional model below the planar surface along the vertical direction.

5. The method for determining the cutting plane for three-dimensional model component division as described in claim 3, characterized in that, The preset sorting strategy includes: Sort according to the area of ​​the candidate printing substrates; or, For each candidate printing substrate, a uniform random number between 0 and 1 is generated, and the substrates are randomly sorted according to their area and the uniform random number.

6. The method for determining the cutting plane for three-dimensional model component division as described in claim 1 or 3, characterized in that, The step of determining the cutting plane of the 3D model according to the detected printing primitive type and a preset cutting strategy includes: If the printed primitive is the initial base, then the initial base is used as the reference and translated along the extension direction of the 3D model to generate several candidate cutting planes; If a candidate cutting plane generated by a certain translation does not meet the printing conditions, then the candidate cutting plane that meets the printing conditions in the previous translation sequence will be taken as the final cutting plane.

7. The method for determining the cutting plane for three-dimensional model component division as described in claim 1 or 3, characterized in that, The step of determining the cutting plane of the 3D model according to the detected printing primitive type and a preset cutting strategy includes: If the printed primitive is the initial base, then based on the initial base, it is gradually translated along the extension direction of the 3D model to generate several candidate cutting planes; If a candidate cutting plane generated by a certain translation does not meet the printing conditions, then the candidate cutting plane that meets the printing conditions in the previous translation sequence will be used as the initial cutting plane. Obtain the center point of the initial cutting plane; Determine the next parallel plane along the direction away from the initial base from the initial cutting plane, and obtain the vertex in that parallel plane that is closest to the initial base; Using the center point as the center of rotation, rotate the normal direction of the initial cutting plane toward the vertex, and use the plane corresponding to the maximum rotation angle as the final cutting plane of the 3D model.

8. The method for determining the cutting plane for three-dimensional model component division as described in claim 7, characterized in that, The step of rotating the initial cutting plane with the center point as the rotation center and rotating the normal direction of the initial cutting plane toward the vertex, and taking the plane corresponding to the maximum rotation angle as the final cutting plane, includes: If a cutting anomaly occurs when the 3D model is cut using the plane corresponding to the current maximum rotation angle, the initial cutting plane is re-rotated by half of the current maximum rotation angle. This process of trial cutting and re-rotation is repeated until no cutting anomalies are found or the iteration termination condition is met. The plane corresponding to the last rotation is then taken as the final cutting plane of the 3D model.

9. The method for determining the cutting plane for three-dimensional model component division as described in claim 2, characterized in that, The process of determining the tip region of the 3D model according to the preset tip region extraction method includes: The 3D model is voxelized to obtain a voxelized mesh representation; A multi-scale protrusion detection algorithm is run on the voxelized mesh representation to identify protrusions in the 3D model and to identify the protrusions as the tip regions.

10. The method for determining the cutting plane for three-dimensional model component division as described in claim 1 or 9, characterized in that, The step of determining the cutting plane of the 3D model according to the detected printing primitive type and a preset cutting strategy includes: If the printing primitive is a pointed area, the boundary contour between the pointed area and the main body of the 3D model is identified, and the plane that passes through the boundary contour and is perpendicular to the extension direction of the pointed area is used as the final cutting plane of the 3D model.

11. The method for determining the cutting plane for three-dimensional model component division as described in claim 1 or 9, characterized in that, The step of determining the cutting plane of the 3D model according to the detected printing primitive type and a preset cutting strategy includes: If the printing primitive is a pointed area, the boundary contour between the pointed area and the main body of the 3D model is identified, and the plane that passes through the boundary contour and is perpendicular to the extension direction of the pointed area is used as the initial cutting plane. Using the initial cutting plane as a reference, the plane is gradually translated along a direction away from the tip region to generate several candidate cutting planes; If a candidate cutting plane generated by a certain translation does not meet the printing conditions, then the candidate cutting plane that meets the printing conditions in the previous translation sequence will be taken as the final cutting plane.

12. The method for determining the cutting plane for three-dimensional model component division as described in claim 1 or 9, characterized in that, The step of determining the cutting plane of the 3D model according to the detected printing primitive type and a preset cutting strategy includes: If the printed primitive is a pointed area, the boundary contour between the pointed area and the main body of the 3D model is identified, and the plane that passes through the boundary contour and is perpendicular to the extension direction of the pointed area is used as the initial cutting plane. Using the initial cutting plane as a reference, the plane is gradually translated along a direction away from the tip region to generate several candidate cutting planes; If a candidate cutting plane generated by a certain translation does not meet the printing conditions, then the candidate cutting plane is taken as the target plane, and the previous candidate cutting plane that meets the printing conditions is taken as the plane to be rotated. Using the center of the plane to be rotated as the rotation center, rotate the normal of the plane to be rotated toward the target plane by a preset angle to obtain the updated initial cutting plane; Repeat the translation to generate candidate cutting planes and plane rotation to update the planes until the angle between the plane to be rotated and the target plane is less than a preset angle threshold. The last candidate cutting plane that meets the printing conditions is taken as the final cutting plane of the 3D model.

13. The method for determining the cutting plane for three-dimensional model component division as described in claim 9, characterized in that, The multi-scale protrusion detection algorithm running on the voxelized mesh representation to identify protrusions in the 3D model includes: Convolution operation is performed on the voxelized mesh representation based on several preset binary templates to obtain the local maximum value corresponding to each binary template, and the voxel position corresponding to the local maximum value is used as a candidate point for convexity at a fine scale. Clustering the detected candidate protrusions, merging candidate protrusions belonging to the same protrusion region, and identifying them as the fine-scale protrusion portions; and / or, The preset binary template is scaled up to generate at least one scaled-up template with an expanded receptive field. The scale-expanded template is convolved on the voxelized mesh representation to detect local maxima, and the voxel position corresponding to the local maxima is used as the large-scale convex part.

14. The method for determining the cutting plane for three-dimensional model component division as described in claim 2, characterized in that, The method for determining the T-shaped region of the 3D model according to the preset T-shaped region recognition method includes: The 3D model is voxelized to obtain a voxelized mesh representation; A graph structure is constructed using each voxel in the voxelized mesh representation as a vertex and the adjacency relationship between adjacent voxels as an edge. In a graph structure, for each vertex, obtain the set of neighboring vertices within a preset distance around that vertex; The number of connected components in the set of adjacent vertices is detected. If the number of connected components is greater than or equal to 2, the vertex is identified as a connected vertex in the T-shaped region. The space occupied by the voxels of all connected vertices is taken as the T-shaped region.

15. The method for determining the cutting plane for three-dimensional model component division as described in claim 1 or 14, characterized in that, The step of determining the cutting plane of the 3D model according to the detected printing primitive type and a preset cutting strategy includes: If the printing primitive is a T-shaped region, then obtain all connected components of the T-shaped region; The offset vector is determined based on the centroids of the two connected components; Construct an initial cutting plane that is perpendicular to the offset vector and passes through the centroid of the first connected component, and perform an initial cut on the 3D model using the initial cutting plane; Using the slice generated from the initial cut as the base plane, gradually translate along the direction toward the second connected component to generate several candidate cutting planes; If a candidate cutting plane generated by a translation does not meet the printing conditions, the initial cutting is cancelled, and the candidate cutting plane is used as the final cutting plane of the 3D model. The width of the first connected component along the T-shaped intersection direction is smaller than the width of the second connected component along the T-shaped intersection direction.

16. The method for determining the cutting plane for three-dimensional model component division as described in claim 15, characterized in that, When the total number of connected components in the T-shaped region is greater than 2, the connected component with the largest width along the intersection direction of the T-shape is selected as the second connected component, and all connected components except the first connected component are merged as the first connected component.

17. The method for determining the cutting plane for three-dimensional model component division as described in claim 16, characterized in that, On the side containing the first connected component, the cut surface generated by the cutting forms a potential tip region; On one side containing the second connected component, the cut surface formed by the cutting creates a flat surface, which serves as a potential initial substrate for printing.

18. A method for printing parts of a three-dimensional model, characterized in that: Includes the following steps: Based on the method for determining the cutting plane for subdividing a three-dimensional model according to any one of claims 1 to 17, the cutting plane is obtained to cut the three-dimensional model and obtain the cut sub-parts; Based on the cutting plane, the connection method between the cut sub-components is determined, and the connection structure corresponding to each cut sub-component is generated according to the connection structure generation strategy corresponding to the connection method, thus forming a sub-component model. Print using the component model.

19. The three-dimensional model component printing method as described in claim 18, characterized in that, The process of cutting the 3D model based on the cutting plane to obtain the cut sub-components includes: The 3D model is cut based on the cutting plane, dividing the 3D model into a first cutting sub-part and a second cutting sub-part located on both sides of the cutting plane; The first cutting sub-component has at least one first cutting surface formed by cutting with a cutting plane, and the second cutting sub-component has at least one second cutting surface formed by cutting with a cutting plane, with the first cutting surface and the second cutting surface paired one-to-one.

20. The method for printing parts of a three-dimensional model as described in claim 18 or 19, characterized in that, Execute after obtaining the cut sub-components: Calculate the cross-sectional area of ​​the first or second cutting surface. If the area of ​​either cross-sectional surface is less than a preset cross-sectional area threshold, prompt the user to re-determine the cutting plane or indicate that the cutting plane position is inappropriate; and / or, Calculate the remaining height corresponding to each cutting surface in the first and second cutting sub-components. If the remaining height of all cutting surfaces is less than the preset remaining height threshold, prompt the user to re-determine the cutting plane or the cutting plane position is inappropriate.

21. The three-dimensional model component printing method as described in claim 18, characterized in that, The connection structure generation strategy includes: A matching protruding structure and a recessed structure are respectively generated on the first cutting surface and the second cutting surface; or Recessed structures are generated on both the first and second cutting surfaces, and independent connectors that mate with the recessed structures are generated.

22. A three-dimensional model component printing system, characterized in that: include: A 3D printer for performing the method as described in any one of claims 18 to 21.

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