Three-dimensional modeling and drawing system for complex parts

Abstract

The application belongs to the technical field of data processing of three-dimensional modeling and drawing, and particularly relates to a three-dimensional modeling and drawing system for complex parts. The system comprises a feature map construction unit, a constraint closure solving unit, a three-dimensional modeling generation unit and a drawing semantic mapping unit. The feature map construction unit maps the geometric units, parameter constraints, reference references and drawing annotation objects of the complex part into a multi-layer feature map comprising a geometric topology layer, a design intention layer and a drawing semantic layer. The constraint closure solving unit determines the constraint transmission path between the geometric units according to the multi-layer feature map. The three-dimensional modeling generation unit generates or updates the three-dimensional model according to the constraint transmission path. The drawing semantic mapping unit generates the engineering drawing object corresponding to the features of the three-dimensional model according to the drawing semantic layer. In this way, the three-dimensional model, the parameter constraints and the engineering drawing annotation are updated under the same feature semantics, reducing the invalidation of the annotation reference, the size chain breakage and the mismatch of the reference object after the local modification of the complex part.

Description

Technical Field

[0001] This invention belongs to the field of data processing technology for 3D modeling and drawing, specifically a 3D modeling and drawing system for complex parts. Background Technology

[0002] 3D modeling and drawing systems for complex components are typically used to convert the geometric shape, dimensional parameters, and engineering drawing information of components into editable 3D models and corresponding 2D engineering drawings. Existing conventional solutions are mostly based on parametric modeling, where users create sketch outlines and set modeling operations such as extrusion, rotation, sweep, lofting, chamfering, filleting, and hole features, saving the sequence of each modeling step in the model tree. For complex components with hole systems, channels, steps, stiffeners, curved surface transitions, and multiple reference surfaces, conventional systems generally extract objects such as faces, edges, holes, axes, and contour loops through geometric feature recognition, and then bind them with parameter constraints based on preset feature templates, allowing the model to recalculate the corresponding geometric entities when dimensions change. While these solutions can complete basic 3D modeling, their data organization is still primarily based on geometric shapes and modeling history; the design purpose, reference source, and subsequent drawing reference relationships of geometric features are usually not uniformly expressed.

[0003] In the existing engineering drawing generation process, conventional systems typically perform projection drawing after the 3D model is completed. This generates a 2D view based on view rules such as front view, top view, side view, sectional view, and local magnification. Then, dimensions, datum symbols, geometric tolerances, and technical requirements are generated according to geometric boundaries, hole axes, contour dimensions, and user settings. Some systems combine historical drawing templates or templates of similar parts to match annotation styles for common features such as holes, slots, chamfers, and fillets, and handle the avoidance of dimension lines, leader lines, and symbol positions. Essentially, this approach processes 3D modeling data and 2D drafting data in stages, with engineering drawing objects largely relying on projection results, geometric numbering, or template matching results. When complex parts undergo local modifications, the original projection boundaries, hole axis references, dimension chain relationships, and datum reference objects may change with topology changes. The system needs to re-identify annotation objects or the drafting results need to be manually corrected.

[0004] The main technical problem with existing technologies is the lack of a unified data expression and constraint transfer mechanism for the geometric topological relationships, design intent relationships, and drafting semantic relationships of complex components. This results in a lack of a stable logical closed loop between 3D model generation, parameter constraint updates, and engineering drawing annotation references. For holes, slots, chamfers, transition surfaces, and datum surfaces with similar geometric shapes but different design functions, the system struggles to determine the dimension chains, datum chains, and annotation reference relationships they should follow based on the internal relationships of the model. Feature objects formed during the geometric modeling stage cannot directly support the binding of dimensions, sections, datums, and tolerances during the drawing stage, and the annotation objects generated during the drawing stage also fail to reflect the true source of constraints for 3D features. Consequently, when there are local changes to the model, feature merging or splitting, or datum replacement, problems such as the model being reconstructable but annotation references becoming invalid, dimension chains breaking, datum object mismatches, or the need for complete regeneration of drawing objects can easily occur. Summary of the Invention

[0005] The purpose of this invention is to provide a 3D modeling and drawing system for complex parts, which can solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A 3D modeling and drawing system for complex parts includes a feature map construction unit, a constraint closure solution unit, a 3D model generation unit, and a drawing semantic mapping unit. The feature map construction unit is used to map the geometric units, parameter constraints, reference references and drawing annotation objects of complex parts into a multi-layer feature map containing a geometric topology layer, a design intent layer and a drawing semantic layer; The constraint closure solving unit is used to determine the constraint transfer path between geometric units based on the multi-layer feature map. The 3D modeling generation unit is used to generate or update the 3D model based on the constraint transfer path; The drawing semantic mapping unit is used to generate engineering drawing objects corresponding to the features of the three-dimensional model based on the drawing semantic layer.

[0007] Preferably, the feature map construction unit includes a basic geometric unit extraction process; The basic geometric unit extraction process is used to extract regions, boundary loops, hole axes, channel centerlines, surface transition zones, chamfered continuum chains, and reference candidate surfaces from 3D model data, sketch outline data, and design parameter data. Furthermore, spatial adjacency identifiers, feature attribution identifiers, and parameter source identifiers are configured for the basic geometric units, enabling modeling data from different sources to enter the same three-dimensional modeling feature expression space.

[0008] Preferably, the design intent layer defines the set of geometric units in the geometric topology layer through feature role tags, baseline dependency tags, and parameter constraint tags; The feature role labels are used to distinguish the main outline, mounting hole system, positioning groove, transition surface and auxiliary chamfer, and the datum dependency labels are used to record the reference relationship of geometric units relative to the main datum, auxiliary datum and local datum; The parameter constraint labels are used to record dimension-driven, coaxial, parallel, symmetric, and equidistant constraints.

[0009] Preferably, the drafting semantic layer establishes a binding relationship between the feature roles in the design intent layer and the engineering drawing object; The engineering drawing object includes view direction, section area, local magnified area, dimension chain, geometric tolerance reference object and datum symbol reference object, and records the three-dimensional feature source, projection reference path and annotation dependency relationship corresponding to each engineering drawing object, so that the engineering drawing object is not generated by a single two-dimensional projection result.

[0010] Preferably, the basic geometric unit extraction process includes topology unification processing; The topology unification process is used to merge discrete surface regions formed by surface segmentation, chamfering, or Boolean operations into feature candidate clusters according to curvature continuity, boundary ring sharing relationship, and parameter source consistency. The feature candidate clusters are then associated with hole axes, channel centerlines, or reference candidate surfaces, so that the same design features that are locally segmented in complex parts are written into the same set of geometric topology layer nodes.

[0011] Preferably, the design intent layer includes a constraint conflict filtering process; The constraint conflict screening process determines the range of geometric units that can participate in constraint propagation based on feature role labels; The starting and ending datums of constraint propagation are determined based on the datum dependency labels, and mutually exclusive size-driven relationships, symmetry relationships, and coaxial relationships in the same set of geometric elements are identified based on the parameter constraint labels, generating a set of constraint candidate sets for use by the constraint closure solver.

[0012] Preferably, the constraint closure solving unit constructs a directed constraint transfer graph based on the constraint candidate set; In the directed constraint propagation graph, the root node is determined by the baseline dependency label, the propagation priority is determined by the feature role label, and the propagation edge type is determined by the parameter constraint label. When there are multiple propagation paths in the same geometric unit, the constraint closure path is selected according to the baseline level, the integrity of the dimension chain, and the consistency of adjacent features.

[0013] Preferably, the output semantic mapping unit includes a label reference retention process; When a local update occurs in the 3D model, the annotation reference retention process determines the views, dimension chains, geometric tolerance reference objects, and datum symbol reference objects that need to be updated synchronously based on the 3D feature sources, projection reference paths, and annotation dependencies recorded in the cartographic semantic layer, and retains the drawing objects that are not affected by the constrained closure path in the original annotation reference set.

[0014] Preferably, the constraint closure solving unit includes a closure backtracking verification process; The closure backtracking verification process maps the constraint closure path back to the geometric topology layer and the design intent layer, checks the set of geometric units, reference dependency labels and parameter constraint labels involved in the propagation one by one, and generates a set of constraints to be corrected when there are propagation edges that are not supported by feature role labels, so that the 3D modeling generation department can redetermine the local modeling features.

[0015] Preferably, the drawing semantic mapping unit includes a drawing consistency reconstruction process; The drawing consistency reconstruction process determines the affected engineering drawing objects based on the set of constraints to be corrected and the annotation reference retention process. The affected engineering drawing objects are recombined into a drawing update set according to the view source, dimension chain level and datum symbol reference relationship. The drawing update set is then fed back to the multi-layer feature map to synchronously correct the binding relationship in the drawing semantic layer.

[0016] This application maps the geometric units, parametric constraints, datum references, and drawing annotations of complex components into a multi-layered feature map containing a geometric topology layer, a design intent layer, and a drawing semantic layer. The 3D modeling and drawing process can complete constraint calculations and object binding within a unified data structure. The geometric topology layer records the spatial relationships between regions, boundary loops, hole axes, channel centerlines, surface transition zones, chamfer continuum chains, and datum candidate surfaces. The design intent layer records feature roles, datum dependencies, and parametric constraints. The drawing semantic layer records the 3D origins of views, sections, dimension chains, geometric tolerances, and datum symbols. The constraint closure solver determines the constraint propagation path based on the above hierarchical relationships, the 3D modeling generation unit generates or updates the model accordingly, and the drawing semantic mapping unit generates engineering drawing objects based on the drawing semantic layer, establishing a traceable reference relationship between model features and drawing objects. Therefore, when complex components are partially modified, the affected geometric features, parametric constraints, and engineering annotations can be synchronously located along the same feature map, reducing annotation failures caused by changes in geometric numbering, projection boundary changes, or template mismatches.

[0017] This application employs mechanisms such as basic geometric unit extraction, topology unification, constraint conflict screening, constraint closure path selection, annotation reference preservation, and drawing consistency reconstruction to enable finer local control over 3D modeling and drawing updates. The same design feature, separated by surface segmentation, chamfering, or Boolean operations, can be written into the same geometric topology node set according to curvature continuity, boundary loop sharing relationships, and parameter source consistency, reducing the participation of duplicate or incomplete features in subsequent calculations. Constraint conflict screening can eliminate mutually exclusive relationships among dimension-driven, coaxial, parallel, symmetrical, and equidistant constraints, while closure backtracking verification can reverse-check constraint propagation results to the geometric topology layer and design intent layer. The drawing semantic mapping department distinguishes between affected and unaffected drawing objects during model updates and reconstructs the drawing update set according to view source, dimension chain level, and datum symbol reference relationships, ensuring that the drawing update scope matches the model change scope and preventing the repeated generation of irrelevant views and annotations. Attached Figure Description

[0018] Figure 1 A flowchart illustrating the overall process of generating 3D models driven by multi-layer feature maps.

[0019] Figure 2 This is a flowchart of the basic geometric unit extraction and topology unification process.

[0020] Figure 3 Flowchart for determining constraint transfer paths between geometric elements.

[0021] Figure 4 A flowchart for reconstructing the semantic mapping and annotation references of drawings to ensure consistency with the drawings. Detailed Implementation

[0022] In one embodiment, reference Figure 1A 3D modeling and drawing system for complex parts includes a feature map construction unit, a constraint closure solving unit, a 3D modeling generation unit, and a drawing semantic mapping unit. The feature map construction unit maps the geometric units, parameter constraints, datum references, and drafting annotation objects of complex parts into a multi-layered feature map containing a geometric topology layer, a design intent layer, and a drafting semantic layer. The constraint closure solving unit determines the constraint transmission path between geometric units based on the multi-layered feature map. The 3D modeling generation unit generates or updates the 3D model based on the constraint transmission path. The drawing semantic mapping unit generates engineering drawing objects corresponding to the 3D model features based on the drafting semantic layer. In specific implementation, the feature map construction unit receives entity boundary data, sketch outline data, and design parameter data from the 3D modeling environment, and converts faces, edges, holes, slots, surface transition regions, and datum candidate objects into numberable geometric... The unit converts dimension-driven, coaxial, parallel, symmetrical, equidistant, and datum-dependent elements into constraint elements, and converts views, sections, local magnifications, dimension chains, geometric tolerances, and datum symbols into drawing objects. Then, a geometric topology layer, a design intent layer, and a drawing semantic layer are established within the same attribution data container. The constraint closure solving unit determines the adjacency chains that can participate in constraint transmission in the geometric topology layer, determines the constraint start point, constraint edge type, and constraint end point in the design intent layer, and determines the drawing objects affected by model features in the drawing semantic layer. The 3D modeling generation unit performs local generation, local reconstruction, or parameter updates of entity features based on the constraint closure results. The drawing semantic mapping unit transmits the semantic identifiers of 3D features to the engineering drawing objects, enabling complex parts to be referenced and updated using the same set of feature semantics between 3D modeling and engineering drawing, avoiding the drift of annotation objects caused by relying solely on projection boundaries or geometric numbers.

[0023] Specifically, the multi-layer feature map uses nodes, edges, and inter-layer mapping tables to represent complex component data. Nodes in the geometric topology layer record the category, geometric boundary, local coordinates, adjacent objects, and parameter sources of geometric units. Nodes in the design intent layer record feature roles, datum dependencies, dimension-driven relationships, and changeable states. Nodes in the drafting semantic layer record view objects, dimension objects, section objects, geometric tolerance objects, and datum symbol objects. Intra-layer edges describe adjacency, containment, subordination, coaxiality, parallelism, symmetry, and reference relationships between objects within the same layer. Inter-layer edges describe the relationship between the same 3D feature in modeling, constraint, and drawing. In the corresponding relationship, the feature map construction unit generates a global feature identifier for each geometric unit when receiving the component model. The global feature identifier is jointly generated by the geometric topology location, parameter source path and reference path, and does not directly use the temporary number inside the modeling software. The constraint closure solving unit reads the inner edge and inter-layer edge and forms a constraint propagation candidate chain. The 3D modeling generation unit determines which regions, hole axes, channel centerlines and chamfer chains should be reconstructed in groups according to the candidate chain. The drawing semantic mapping unit determines the binding relationship between the engineering drawing object and the 3D model feature according to the inter-layer edge, so that model modification, constraint checking and drawing update are transmitted in the same map.

[0024] ; in, This represents the topological association value between geometric element i and geometric element j. Indicates that the normal direction takes continuous values. This indicates that the boundary rings share values. Indicates the spatial adjacency value. This indicates that the parameter source is consistent and the value is taken from the same source. , , , Represents the weight of the corresponding term and satisfies When the transition zone of a curved surface is split into two regions by chamfering or Boolean operations, if , , , and take , , , ,but The feature map construction unit writes two surface regions into the same feature candidate cluster, when And when other values ​​remain unchanged, The feature map construction unit retains the adjacency relationship between two surface regions but does not directly merge them into the same design feature, thereby enabling geometric continuity and parameter sources to jointly participate in the 3D modeling feature collection.

[0025] In a preferred embodiment, reference Figure 2 The feature map construction unit includes a basic geometric unit extraction process. This process extracts surface regions, boundary loops, hole axes, channel centerlines, surface transition zones, chamfered continuum chains, and reference candidate surfaces from 3D model data, sketch contour data, and design parameter data. It also configures spatial adjacency identifiers, feature attribution identifiers, and parameter source identifiers for each basic geometric unit, allowing modeling data from different sources to enter the same 3D modeling feature expression space. In specific implementations, the 3D model data provides entity boundaries, surface patches, boundary loops, and topological adjacency relationships; the sketch contour data provides constraint contours and center reference lines before stretching, rotating, sweeping, or lofting; and the design parameter data provides dimension names and parameter expressions. The process of extracting basic geometric units involves: forming surface objects based on curvature distribution and boundary closure for surface regions; forming hole axis objects based on cylindrical surface axes, conical surface axes, or sketch center sequence for hole features; forming channel centerline objects based on relatively parallel boundaries and end arcs for slot features; forming chamfer continuous chain objects based on continuous edge chains for chamfers and fillets; and forming datum candidate objects based on area, flatness, reference frequency, and parameter source for datum candidate surfaces. The spatial adjacency identifier records the contact, intersection, encirclement, and distance relationships between geometric units. The feature attribution identifier records the candidate design features to which the geometric unit belongs. The parameter source identifier records the sketch size, modeling operation, or external parameter table that drives the geometric unit.

[0026] In a preferred embodiment, the basic geometric unit extraction process does not use a single entity feature name as the extraction result when processing 3D model data. Instead, it performs source recovery on geometric objects that have been disassembled in the modeling history of complex parts. Source recovery includes backtracking based on sketch contours, correspondence based on parameter names, topological merging based on adjacent regions, and classification based on reference directions. Backtracking of sketch contours involves reading closed loops, open curves, and reference centerlines in the sketch to correspond the end faces, side faces, and hole walls in the extruded entity to the original contour segments. Correspondence of parameter names involves comparing parameter variables in the dimension expression, modeling feature names, and external parameter table fields to classify hole diameters, slot widths, or step heights driven by the same parameter into the same parameter source set. Topological merging of adjacent regions involves forming topological candidate clusters through adjacent edge sharing, boundary loop inclusion, and curvature continuity relationships. Classification of reference directions involves comparing the consistency of candidate surface normals with the directions of the primary reference, auxiliary reference, and local reference, and writing parallel or perpendicular relationships into the geometric topology layer. After source recovery, the geometric unit can simultaneously carry shape information, parameter source information, and reference dependency information.

[0027] Furthermore, the basic geometric unit extraction process includes topology unification processing. This processing merges discrete surface regions formed by surface segmentation, chamfering, or Boolean operations into feature candidate clusters based on curvature continuity, boundary loop sharing, and parameter source consistency. These feature candidate clusters are then associated with hole axes, channel centerlines, or reference candidate surfaces. This ensures that the same design feature, partially segmented in complex components, is written into the same geometric topology layer node set. In practice, the topology unification processing establishes a surface adjacency matrix for the discrete surface regions. The matrix elements consist of the normal angle, common edge length, curvature difference, and parameter source consistency. It is calculated that for step sidewalls with chamfered breaks, the topology unification process does not directly treat the chamfered surface as an independent design feature, but instead writes the chamfered surface as a connecting boundary into the transition relationship between adjacent main surface regions. For multiple hole wall segments formed by Boolean cut, the topology unification process merges multiple hole wall segments into the same hole system candidate cluster based on the hole axis coincidence and hole diameter parameter source. For the case where the curved transition zone is divided into multiple small facets, the topology unification process forms a curved transition candidate cluster based on curvature continuity and boundary ring sharing relationship, and then establishes reference edges between the candidate cluster and the corresponding channel centerline, hole axis, or reference candidate surface.

[0028] In a preferred embodiment, reference Figure 3 The design intent layer defines the set of geometric units in the geometric topology layer through feature role labels, datum dependency labels, and parameter constraint labels. The feature role labels distinguish the main contour, mounting hole system, positioning groove, transition surface, and auxiliary chamfer. The datum dependency labels record the reference relationships of geometric units relative to the primary datum, auxiliary datum, and local datum. The parameter constraint labels record dimension-driven, coaxial, parallel, symmetric, and equidistant constraints. In specific implementation, after reading feature candidate clusters from the geometric topology layer, the design intent layer configures role labels according to the geometric category, parameter source, and datum dependency path of the candidate clusters. When a candidate cluster consists of multiple hole axes of the same diameter and relative to each other... When the primary and auxiliary datums have grouped positioning dimensions, they are used for mounting hole systems. When the candidate cluster consists of relatively parallel boundaries, end arcs, and channel centerlines and is driven by the slot width parameter, it is used for positioning slots. When the candidate cluster consists of continuous curvature surface regions and is located between two main contours, it is used for transition surfaces. When the candidate cluster is located at the intersection of two adjacent surface regions and the parameter source is a boundary processing operation, it is used for auxiliary chamfering. The datum dependency label records the reference path of each feature candidate cluster with the datum candidate surface as the root object. The parameter constraint label uniformly writes the dimension expression, constraint type, and constraint object into the design intent layer, so that subsequent constraint closure calculations can distinguish geometrically similar objects with different design roles.

[0029] In a preferred embodiment, the reference dependency label in the design intent layer uses a directed reference path to represent the reference chain of complex parts. The directed reference path consists of reference nodes, feature nodes, and constraint edges. The main reference node corresponds to the surface region or axis referenced by multiple dimension chains in the part modeling. The auxiliary reference node corresponds to the surface region, axis, or center surface that shares the direction or position with the main reference. The local reference node corresponds to the temporary reference on which the local hole system, positioning groove, or local curved surface transition depends. The constraint edges record relationships such as dimension driving, parallelism, perpendicularity, coaxiality, symmetry, and equidistance. The design intent layer records the path start point, path end point, constraint edge type, and parameter source for each reference path. When the same hole axis has both coaxial constraint and dimension positioning constraint, the design intent layer determines whether the coaxial relationship is an internal constraint of the hole system and whether the dimension positioning relationship is a relative reference constraint of the hole system based on the feature role label, avoiding the incorrect propagation of the internal arrangement relationship of the hole system as a change constraint on the main body contour. The parameter constraint label records the applicable scope of the constraint through the constraint object set, so that the constraint propagation boundary can be limited when local features are modified.

[0030] ; in, This represents the matching value assigned to the feature role of the k-th feature candidate cluster. Indicates the geometric category matching value. Indicates the baseline dependency matching value. This indicates that the parameter source matches the value. This indicates a conflicting value that is incompatible with other roles. , , , This represents the weight of the corresponding item and is a non-negative number. In a candidate cluster of pore systems, if the geometric category is porous with the same diameter and the weight is taken as... The benchmark depends on completeness and is taken. The aperture and positioning dimensions are from the same parameter table and are taken as follows: It has a low conflict with the positioning slot role and takes ,and , , , ,but The design intent layer uses candidate clusters for mounting hole systems. When the same candidate cluster lacks a baseline dependency and is selected... hour, The design intent layer retains candidate clusters as geometric features to be confirmed and restricts their participation in the baseline chain propagation.

[0031] Furthermore, the design intent layer includes a constraint conflict screening process. This process determines the range of geometric units eligible for constraint propagation based on feature role labels, determines the starting and ending datums for constraint propagation based on datum dependency labels, and identifies mutually exclusive size-driven relationships, symmetry relationships, and coaxial relationships within the same set of geometric units based on parameter constraint labels. This generates a candidate set of constraints for the constraint closure solver to use. In practice, the constraint conflict screening process reads all constraint edges within the same set of geometric units, merging constraint edges with the same starting and ending points and of the same type. Size-driven relationships with different starting points but the same ending point are included in conflict comparison. Cases where the symmetry center plane and the coaxial center line simultaneously define the position of the same hole axis are included in mutual exclusion comparison. Cases where equidistant arrangement constraints and individual size positioning constraints simultaneously define the middle hole position of the hole system are included in range comparison. Then, based on the feature role labels, it is determined which constraints are dominant constraints and which constraints are derived constraints. The dominant constraints are written into the constraint candidate set, the derived constraints are retained as verification constraints, and the mutually exclusive constraints that cannot be explained by the derived relationship are written into the set to be corrected, so that mutual exclusion relationships are not simultaneously passed to the 3D model when solving the constraint closure.

[0032] In a preferred embodiment, the constraint closure solving unit constructs a directed constraint transfer graph based on the constraint candidate set. In this graph, the root node is determined by a datum dependency label, the propagation priority is determined by a feature role label, and the propagation edge type is determined by a parameter constraint label. When multiple propagation paths exist within the same geometric unit, the constraint closure path is selected according to the datum level, dimension chain integrity, and consistency of adjacent features. In specific implementations, the root node of the directed constraint transfer graph includes a principal datum plane, a principal datum axis, and a center plane determined by the principal datum plane. The propagation edges include dimension-driven edges and coaxial edges. The propagation priority of edges, parallel edges, symmetrical edges, and equidistant edges is determined according to the feature role. The datum dependency of the main contour and mounting hole system takes precedence over the local boundary dependency of the auxiliary chamfer. The slot width drive of the positioning groove takes precedence over the boundary processing drive of the chamfer continuous chain. The continuity relationship of the transition surface is restricted to adjacent main contours. The constraint closure solving unit calculates the datum level score, the dimension chain integrity score, and the adjacent feature consistency score for each candidate path from the root node to the target feature node. It selects the path that satisfies the constraint type continuity and has fewer conflict terms as the closure path and passes the closure path to the 3D modeling generation unit.

[0033] ; in, This represents the closure selection value of the candidate constraint propagation path p. This indicates the value of the u-th baseline level matching item. This indicates the complete value of the v-th dimension chain. This indicates the conflicting value of the w-th constraint. , , Let m represent the weight of the corresponding item, n represent the number of reference level items involved in the calculation, h represent the number of dimension chain items involved in the calculation, and m represent the number of conflicting items involved in the calculation. In the path selection for hole system positioning relative to the main datum, if the path... It has two baseline level matching and takes , It has two complete value values ​​for the dimension chain and takes , There is one minor conflict and If the corresponding weights are all set to 0.2 and the conflict weight is set to 0.1, then... If the path If the dimension chain is complete but the baseline level matches and two conflicts occur, then its closure selection value is lower than [value missing]. The constraint closure solver is selected As a path for updating the pore system.

[0034] In this embodiment, the 3D modeling generation unit performs local reconstruction of complex component models according to the closure path. The local reconstruction includes feature node positioning, dependency parameter reading, geometric unit updating, and topology result writing back. The feature node positioning determines the main contour, mounting hole system, positioning groove, transition surface, or auxiliary chamfer that needs to be updated according to the closure path. The dependency parameter reading reads the parameter expressions corresponding to dimension-driven, coaxial, parallel, symmetric, and equidistant constraints from the design intent layer. The geometric unit updating performs local geometric calculations on the face region, boundary loop, hole axis, and groove centerline. The topology result writing back writes the updated geometric adjacency relationship, parameter source identifier, and feature attribution identifier back to the geometric topology layer. When updating the mounting hole system, the 3D modeling generation unit retains the coaxial or equidistant relationship within the hole system and updates the overall position of the hole system according to the reference dependency path. When updating the positioning groove, it retains the groove width parameter and groove centerline constraint and recalculates the groove end contour according to the change result of the main contour. When updating the auxiliary chamfer, it regenerates the chamfer continuum chain according to the update result of the adjacent face region. In this way, each type of feature receives different constraint transmissions according to its own design role.

[0035] In a preferred embodiment, reference Figure 4The drafting semantic layer establishes a binding relationship between the feature roles in the design intent layer and the engineering drawing objects. These engineering drawing objects include view directions, section regions, magnified local regions, dimension chains, geometric tolerance reference objects, and datum symbol reference objects. It also records the 3D feature source, projection reference path, and annotation dependencies corresponding to each engineering drawing object, ensuring that the engineering drawing objects are not generated dependent on a single 2D projection result. In specific implementation, the drafting semantic layer reads feature roles such as the main outline, mounting hole system, positioning groove, transition surface, and auxiliary chamfer from the design intent layer, generating usable view candidate objects for each feature role. The view direction is determined by... The main feature direction, hole axis direction, channel centerline direction, and datum plane normal are jointly determined. The sectioning area is jointly determined by the internal hole system, deep groove, occluded surface region, and datum reference path. The locally magnified area is jointly determined by small-size chamfers, transition surface boundaries, and dense hole system. The dimension chain is bound to the dimension-driven path in the parameter constraint label. The geometric tolerance reference object is bound to the feature role and datum dependency label. The datum symbol reference object is bound to the candidate surface or axis of the main datum, auxiliary datum, and local datum. The drawing semantic layer records the engineering drawing object with the three-dimensional feature source and projection reference path, and does not use the temporary number of the two-dimensional line segment as the unique reference.

[0036] Furthermore, the drawing semantic mapping unit includes a label reference retention process. When a local update occurs in the 3D model, this process determines the views, dimension chains, geometric tolerance reference objects, and datum symbol reference objects that need to be updated synchronously based on the 3D feature sources, projection reference paths, and label dependencies recorded in the drawing semantic layer. It also retains drawing objects not affected by the constraint closure path in the original label reference set. In specific implementation, the label reference retention process receives the closure path output by the constraint closure solution unit and the topology update result output by the 3D modeling generation unit, and matches the feature nodes in the closure path with the drawing objects in the drawing semantic layer. The matching process involves the following steps: if the start, end, or intermediate datum node of a dimension chain is located within the closure path, the dimension chain is written into the synchronous update set; if the measured feature of a geometric tolerance reference object is located within the closure path but the datum symbol reference object is not, the geometric tolerance reference object is written into the numerical or reference position update set; if a view only contains unaffected main contours or auxiliary chamfers, the view retains its original projection reference path; if a sectioning region passes through the updated hole system or channel, the sectioning region is written into the recalculation set. This annotation reference retention process thus limits the drawing update range to the semantic objects involved in the 3D feature changes.

[0037] ; in, This represents the update association value of the q-th drawing object. The value indicating whether the 3D feature referenced by the drawing object is located within the closure path. The value indicates whether the reference node of the drawing object is located in the closure path. This value indicates whether the dimension chain containing the drawing object intersects with the closure path. , , Indicates the weight of the corresponding item and satisfies In a certain hole spacing dimension annotation, if the axis of the annotated hole is located in the closure path and is taken as... The baseline node remained unchanged and was taken. The dimension chain intersects with the closure path and is taken. ,and , , ,but The drawing semantic mapping unit writes the drawing object into the synchronous update set. If the view boundary only contains unchanged auxiliary chamfers and all three values ​​are 0, then... The drawing objects remain in the original annotation reference set.

[0038] In a preferred embodiment, the drawing semantic mapping unit also performs projection reference path solidification when generating engineering drawing objects. This projection reference path solidification writes the 3D feature source, projection view direction, projection boundary type, annotation dependency, and datum reference path into the drafting semantic layer. For the external dimensions of the main outline, the projection reference path records the boundary ring, view direction, and start and end points of the dimension chain of the main outline surface region. For the positioning dimensions of the mounting hole system, the projection reference path records the hole axis, hole system role label, primary or auxiliary datum reference object, and positioning dimension expression. For the width or depth dimensions of the positioning groove, the projection reference path records the groove centerline, groove wall surface region, groove width parameter, and local datum reference object. For the annotation of transition surfaces and auxiliary chamfers, the projection reference path records the surface transition zone, chamfer continuous chain, and its adjacent main surface region. This allows the engineering drawing object to recover the reference object based on the 3D feature source after model reconstruction, rather than re-matching based on the similar position of 2D projection line segments.

[0039] In a preferred embodiment, the constraint closure solving unit includes a closure backtracking verification process. This process maps the constraint closure path backward to the geometric topology layer and the design intent layer, checks each set of geometric units, baseline dependency labels, and parameter constraint labels involved in the propagation, and generates a set of constraints to be corrected when propagation edges are not supported by feature role labels. This set is then used by the 3D modeling generation unit to re-determine local modeling features. In specific implementation, the closure backtracking verification process traverses backward from the target feature node of the closure path to the root node, reads the set of geometric units and parameter constraint labels corresponding to each propagation edge, and checks the propagation edges. The system checks whether a corresponding reference dependency label exists, whether the feature role of the target feature node allows acceptance of this type of constraint, and whether adjacent features are mistakenly included in the update range due to closure paths. When the coaxial constraint of the mounting hole system is incorrectly propagated to the main contour surface region, the closure backtracking verification process identifies that the propagation edge lacks the support of the main contour role and writes it into the set of constraints to be corrected. When the symmetric constraint of the positioning slot crosses the local reference and is propagated to the main reference, the closure backtracking verification process identifies that the constraint endpoint exceeds the reference dependency path and writes it into the set of constraints to be corrected. The 3D modeling generation unit re-segments the local feature nodes or adjusts the constraint boundaries according to the set of constraints to be corrected.

[0040] ; in, This represents the backtracking outlier of the z-th propagation edge. This indicates the allowed propagation level of the propagation edge within the design intent layer. This indicates the actual propagation level of the propagation edge within the closure path. This indicates that the feature roles of the propagation edge do not match the values. The parameter constraint conflict values ​​of the propagation edge are represented. , This indicates the weight of anomalies. When the auxiliary chamfer boundary treatment constraint is propagated to the mounting hole system positioning dimensions, if the allowed propagation level is 1 but the actual propagation level is 3, then... If the characteristic role does not match and is taken Parameter constraint conflict and take ,and , ,but The closure backtracking verification process writes the z-th propagation edge into the constraint set to be corrected. If the allowed propagation level and the actual propagation level of a certain size driving edge are the same and both abnormal values ​​are 0, then the propagation edge is retained in the closure path.

[0041] In this embodiment, after the set of constraints to be corrected is written into the multi-layer feature map, the feature map construction unit, the constraint closure solving unit, and the 3D modeling generation unit jointly perform local recalculation. The local recalculation does not delete the complete 3D model, nor does it regenerate all engineering drawing objects. Instead, it locates the source of error around the propagation edges in the set of constraints to be corrected. If the source of error is that the merging range of feature candidate clusters in the geometric topology layer is too wide, the feature map construction unit splits the candidate clusters according to the parameter source identifier and the baseline dependency label. If the source of error is that the feature role label configuration in the design intent layer is inconsistent, the design intent layer reconfigures the role labels according to the role matching value. If the source of error is that the constraint candidate set contains mutually exclusive relationships, the constraint conflict screening process adjusts the mutually exclusive constraints into dominant constraints or verification constraints. If the source of error is that the closure path crosses the local baseline boundary, the constraint closure solving unit recalculates the starting baseline and the ending feature. After the local recalculation is completed, the 3D modeling generation unit generates a new topology update result and writes it back to the geometric topology layer, so that the subsequent output semantic mapping unit can receive the model features that have been backtracked and verified.

[0042] In a preferred embodiment, the drawing semantic mapping unit includes a drawing consistency reconstruction process. This process determines the affected drawing objects based on the set of constraints to be corrected and the annotation reference retention process. The affected drawing objects are then recombined into a drawing update set according to view source, dimension chain level, and datum symbol reference relationship. This drawing update set is then fed back to the multi-layer feature map to synchronously correct the binding relationships in the drawing semantic layer. In specific implementation, the drawing consistency reconstruction process reads the propagation edges from the set of constraints to be corrected, the synchronous update set from the annotation reference retention process, and the original annotation references. The annotation reference set divides the drawing objects into preserved objects, updated objects, and reconstructed objects. The preserved objects continue to use the original 3D feature sources and projection reference paths. The updated objects retain the view position and annotation semantics but recalculate dimension values, reference endpoints, or symbol attachment objects. The reconstructed objects regenerate projection reference paths according to the new view sources, dimension chain levels, and datum symbol reference relationships. After the drawing update set is written back to the drawing semantic layer, the original mismatched binding relationships are replaced with new inter-layer mapping edges, and the unaffected inter-layer mapping edges are retained, so that the 3D model, constraint closure results, and drawing objects maintain the same data state.

[0043] Furthermore, the drawing consistency reconstruction process parses the dimension chain hierarchy when combining the drawing update set. The dimension chain hierarchy includes the overall dimension chain from the main datum to the main body contour, the positioning dimension chain from the main datum or auxiliary datum to the mounting hole system, the local dimension chain from the local datum to the positioning slot, and the boundary dimension chain from adjacent main body surface regions to transition surfaces or auxiliary chamfers. The drawing consistency reconstruction process determines which level of dimension chain the affected engineering drawing object belongs to, and searches for common datum nodes and common feature nodes within the same level of dimension chain. If the affected object belongs to the overall dimension chain, the reconstruction scope is extended to the view source and datum symbol reference relationship related to the main body contour. If the affected object belongs to the positioning dimension chain, the reconstruction scope is limited to the mounting hole system and its reference datum. If the affected object belongs to the local dimension chain, the reconstruction scope is limited to the positioning slot, local datum, and related local magnified areas. If the affected object belongs to the boundary dimension chain, the reconstruction scope is limited to the transition surface, auxiliary chamfer, and its adjacent surface regions. The drawing update set is thus formed into multiple non-confusing update groups according to the dimension chain hierarchy.

[0044] ; in, This represents the grouping value of the y-th drawing object when it enters the drawing update set. This indicates that the view source has consistent values. This indicates that the size chain hierarchy takes consistent values. This indicates that the reference symbol takes a consistent value. This indicates that the three-dimensional features have a consistent source and take values. , , , Indicates the weight of the corresponding item and satisfies When the positioning dimensions and hole diameter annotations of the mounting hole system are affected simultaneously, if the view sources of the two engineering drawing objects are consistent and taken as... Consistent size chain hierarchy and taking The reference to the base symbol is consistent and taken The three-dimensional features have a consistent source and are taken If the corresponding weights are all set to 0.25, then The drawing consistency reconstruction process groups two engineering drawing objects into the same drawing update group. If the view source of an auxiliary chamfer annotation is the same but the dimension chain level and the three-dimensional feature source are different, the group value decreases, and the drawing consistency reconstruction process retains it in an independent update group or the original annotation reference set.

[0045] In a preferred embodiment, the multi-layer feature map also records the correspondence between model version status and drawing status. The model version status includes a set of geometric topology layer nodes, a set of design intent layer labels, a set of constraint closure paths, and a set of topology update results. The drawing status includes a set of view objects, a set of dimension chains, a set of geometric tolerance references, a set of datum symbol references, and a set of projection reference paths. When a complex part is updated from an old version to a new version, the feature map construction unit regenerates the set of geometric topology layer nodes for the new version. The constraint closure solving unit maps the datum dependency labels, parameter constraint labels, and feature role labels in the old and new versions. The drawing semantic mapping unit matches the drawing status in the old version with the three-dimensional feature sources in the new version. Engineering drawing objects that match are entered into the retention object or update object. Engineering drawing objects that do not match and are related to the constraint set to be corrected are entered into the reconstruction object. This ensures that changes in model version do not cause all engineering drawing objects to lose their original semantic sources.

[0046] In this embodiment, when the system processes 3D modeling of complex parts, the input data can be an existing 3D model file, a parametric model generated from a 2D sketch, or a design parameter table containing dimensional parameters and datum information. The feature map construction unit writes different input data into the same map data container and establishes a geometric topology layer, a design intent layer, and a drafting semantic layer. The constraint closure solving unit reads the constraint candidate set in the design intent layer and calculates the constraint closure path. The 3D modeling generation unit generates or updates the main body contour, mounting hole system, positioning groove, transition surface, and auxiliary chamfer according to the closure path. The drawing semantic mapping unit generates view direction, section area, local magnified area, dimension chain, geometric tolerance reference object, and datum symbol reference object according to the binding relationship in the drafting semantic layer. When the user or external parameter table modifies the hole spacing, groove width, main body contour size, or datum reference object, the change information is first written into the design intent layer. The constraint closure path limits the model update range, the annotation reference retention process limits the engineering drawing update range, and the drawing consistency reconstruction process reorganizes the affected objects, so that the 3D model and engineering drawing objects are updated synchronously based on the same feature map.

[0047] In another preferred embodiment, the system performs consistent storage of multi-layer feature maps after generating or updating the 3D model. The consistent storage includes a geometric unit storage table, a feature role storage table, a datum dependency storage table, a parameter constraint storage table, and a cartographic semantic storage table. The geometric unit storage table records the identifiers and adjacency relationships of surface regions, boundary loops, hole axes, channel centerlines, surface transition zones, chamfer continuum chains, and datum candidate surfaces. The feature role storage table records the role labels of the main contour, mounting hole system, positioning slots, transition surfaces, and auxiliary chamfers. The datum dependency storage table records the reference paths between the main datum, auxiliary datum, and local datum. The parameter constraint storage table records dimension-driven, coaxial, parallel, symmetric, and equidistant constraints. The cartographic semantic storage table records the binding relationships between view directions, section regions, local magnified regions, dimension chains, geometric tolerance reference objects, and datum symbol reference objects and 3D feature sources. The consistent storage is refreshed simultaneously with the topology update results and cartographic update set after each model update, so that the existing feature semantics can continue to be used in the next modeling modification.

[0048] In this embodiment, when the system generates drawings for complex parts, the drawing semantic mapping unit does not independently identify all dimensions and symbols based on the two-dimensional projection results. Instead, it reads the three-dimensional feature sources already bound in the drawing semantic layer, generates projection objects of the main outline, mounting hole system, positioning groove, transition surface, and auxiliary chamfer according to the view direction, generates the outer dimensions, hole spacing dimensions, groove width dimensions, and local boundary dimensions according to the dimension chain, generates datum symbol reference objects according to the datum dependency tags, and generates geometric tolerance reference objects according to the feature role tags and parameter constraint tags. The generated engineering drawing objects are written back to the drawing semantic layer and inter-layer mapping edges are established with the corresponding three-dimensional feature nodes. When the model is partially reconstructed, the drawing semantic mapping unit reads the three-dimensional source and annotation dependency relationship of the original engineering drawing object from the inter-layer mapping edge, recalculates the projection reference path within the affected object range, and retains the original binding relationship within the unaffected object range, so that the update of the complex part engineering drawing and the three-dimensional modeling changes maintain a traceable data association.

[0049] It should be understood that although the steps in the flowcharts of this application's embodiments are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some of the steps in the figures may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be performed alternately or in turn with other steps or at least a portion of the sub-steps or stages of other steps.

[0050] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A 3D modeling and drawing system for complex parts, characterized in that, It includes a feature map construction unit, a constraint closure solving unit, a 3D modeling generation unit, and a map output semantic mapping unit; The feature map construction unit is used to map the geometric units, parameter constraints, reference references and drawing annotation objects of complex parts into a multi-layer feature map containing a geometric topology layer, a design intent layer and a drawing semantic layer; The constraint closure solving unit is used to determine the constraint transfer path between geometric units based on the multi-layer feature map. The 3D modeling generation unit is used to generate or update the 3D model based on the constraint transfer path; The drawing semantic mapping unit is used to generate engineering drawing objects corresponding to the features of the three-dimensional model based on the drawing semantic layer.

2. The 3D modeling and drawing system for complex parts according to claim 1, characterized in that, The feature map construction unit includes a basic geometric unit extraction process; The basic geometric unit extraction process is used to extract regions, boundary loops, hole axes, channel centerlines, surface transition zones, chamfered continuum chains, and reference candidate surfaces from 3D model data, sketch outline data, and design parameter data. Furthermore, spatial adjacency identifiers, feature attribution identifiers, and parameter source identifiers are configured for the basic geometric units, enabling modeling data from different sources to enter the same three-dimensional modeling feature expression space.

3. The 3D modeling and drawing system for complex parts according to claim 1, characterized in that, The design intent layer defines the set of geometric units in the geometric topology layer through feature role labels, baseline dependency labels, and parameter constraint labels; The feature role labels are used to distinguish the main outline, mounting hole system, positioning groove, transition surface and auxiliary chamfer, and the datum dependency labels are used to record the reference relationship of geometric units relative to the main datum, auxiliary datum and local datum; The parameter constraint labels are used to record dimension-driven, coaxial, parallel, symmetric, and equidistant constraints.

4. The 3D modeling and drawing system for complex parts according to claim 3, characterized in that, The drafting semantic layer establishes a binding relationship between the feature roles in the design intent layer and the engineering drawing object; The engineering drawing object includes view direction, section area, local magnified area, dimension chain, geometric tolerance reference object and datum symbol reference object, and records the three-dimensional feature source, projection reference path and annotation dependency relationship corresponding to each engineering drawing object, so that the engineering drawing object is not generated by a single two-dimensional projection result.

5. The 3D modeling and drawing system for complex parts according to claim 2, characterized in that, The basic geometric unit extraction process includes topology unification processing; The topology unification process is used to merge discrete surface regions formed by surface segmentation, chamfering, or Boolean operations into feature candidate clusters according to curvature continuity, boundary ring sharing relationship, and parameter source consistency. The feature candidate clusters are then associated with hole axes, channel centerlines, or reference candidate surfaces, so that the same design features that are locally segmented in complex parts are written into the same set of geometric topology layer nodes.

6. The 3D modeling and drawing system for complex parts according to claim 3, characterized in that, The design intent layer includes a constraint conflict filtering process; The constraint conflict screening process determines the range of geometric units that can participate in constraint propagation based on feature role labels; The starting and ending datums of constraint propagation are determined based on the datum dependency labels, and mutually exclusive size-driven relationships, symmetry relationships, and coaxial relationships in the same set of geometric elements are identified based on the parameter constraint labels, generating a set of constraint candidate sets for use by the constraint closure solver.

7. The 3D modeling and drawing system for complex parts according to claim 4, characterized in that, The constraint closure solving unit constructs a directed constraint transfer graph based on the constraint candidate set; In the directed constraint propagation graph, the root node is determined by the baseline dependency label, the propagation priority is determined by the feature role label, and the propagation edge type is determined by the parameter constraint label. When there are multiple propagation paths in the same geometric unit, the constraint closure path is selected according to the baseline level, the integrity of the dimension chain, and the consistency of adjacent features.

8. The 3D modeling and drawing system for complex parts according to claim 7, characterized in that, The output semantic mapping unit includes a label reference preservation process; When a local update occurs in the 3D model, the annotation reference retention process determines the views, dimension chains, geometric tolerance reference objects, and datum symbol reference objects that need to be updated synchronously based on the 3D feature sources, projection reference paths, and annotation dependencies recorded in the cartographic semantic layer, and retains the drawing objects that are not affected by the constrained closure path in the original annotation reference set.

9. The 3D modeling and drawing system for complex parts according to claim 8, characterized in that, The constraint closure solving unit includes a closure backtracking verification process; The closure backtracking verification process maps the constraint closure path back to the geometric topology layer and the design intent layer, checks the set of geometric units, reference dependency labels and parameter constraint labels involved in the propagation one by one, and generates a set of constraints to be corrected when there are propagation edges that are not supported by feature role labels, so that the 3D modeling generation department can redetermine the local modeling features.

10. The 3D modeling and drawing system for complex parts according to claim 9, characterized in that, The drawing semantic mapping department includes a drawing consistency reconstruction process; The drawing consistency reconstruction process determines the affected engineering drawing objects based on the set of constraints to be corrected and the annotation reference retention process. The affected engineering drawing objects are recombined into a drawing update set according to the view source, dimension chain level and datum symbol reference relationship. The drawing update set is then fed back to the multi-layer feature map to synchronously correct the binding relationship in the drawing semantic layer.

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