A feature validity maintenance method based on topology element naming

Abstract

The application discloses a feature validity maintenance method based on topological element naming, which comprises the following steps: setting original names of topological elements of an original geometric model based on a sketch and a feature generation mode, setting reference names of the topological elements when topological elements of a new geometric model refer to the original geometric model, setting the reference names based on original names, local topological information, direction information and a naming storage set of surface elements, setting the reference names based on original names, local topological information, direction information and geometric parameters of edge elements and the naming storage set, setting the reference names based on original names, local topological information, direction information and information of adjacent edges of point elements and the naming storage set, identifying the topological elements of the new geometric model based on the reference names to obtain unique identification results, and using effective information in a design process to hierarchize design element reference names and giving a step-by-step identification mechanism for eliminating reference ambiguity, so as to maintain data consistency.

Description

Technical Field

[0001] This invention belongs to the field of computer-supported collaborative design, specifically relating to a method for maintaining the validity of features based on topological element naming. Background Technology

[0002] Parametric feature modeling technology is a core technology of industrial software, and permanent naming of topological elements is one of the key technologies supporting parametric modeling. The purpose of permanent naming of topological elements is primarily to ensure that elements can be correctly referenced during interactive selection after model modifications. The research content mainly includes two aspects (such as...). Figure 1 As shown in the figure: First, there are issues with the naming and inheritance of original element names and the differentiation of referenced elements during the model construction process. The differentiation problem is due to ambiguity caused by the same original name of elements. Second, there is the issue of re-matching referenced elements during the model reconstruction process after design modification. The matching problem is that the old referenced elements need to automatically identify new elements that meet the user's design intentions in the reconstructed model. The identified new elements may be one, multiple, or even non-existent. This requires automatically eliminating the ambiguity of the identification results or making decisions through user interaction to avoid reconstruction failure.

[0003] However, existing permanent naming mechanisms for topological elements have the following main problems: First, the methods lack a general mechanism for specific implementation. Some only propose theoretical ideas but lack methodological implementation, while others rely on self-built prototype systems to verify the proposed methods, making them difficult to reproduce. Second, the ability to handle ambiguity is limited, especially the degree of freedom and flexibility in modifying model design is insufficient, and the user's implicit design intent is difficult to maintain well after parametric editing. Summary of the Invention

[0004] This invention provides a feature validity maintenance method based on topological element naming. It utilizes valid information from the design process to hierarchically design element reference names and provides a step-by-step identification mechanism to eliminate reference ambiguity, thereby facilitating data consistency maintenance.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] The first aspect of this invention provides a method for maintaining the feature validity based on topological element naming, comprising:

[0007] Based on the sketch and feature generation method, the original names are set for the topological elements of the original geometric model, and the original names of each topological element are used to construct a named storage set.

[0008] When a topological element in a new geometric model references an element in the original geometric model, the reference name of the topological element is set. When the topological element is a face element, the reference name is set based on the original name of the topological element, local topological information, orientation information, and the named storage set. When the topological element is an edge element, the reference name is set based on the original name of the topological element, local topological information, orientation information, geometric parameters, and the named storage set. When the topological element is a point element, the reference name is set based on the original name of the topological element, local topological information, orientation information, information of adjacent edges, and the named storage set.

[0009] The topological elements of the new geometric model are identified based on their reference names to obtain unique identification results.

[0010] Furthermore, after feature editing on the original geometric model, a new geometric model is formed. For topological elements in the new geometric model that are consistent with the original geometric model, the names of the topological elements are set by directly inheriting the original names; for topological elements in the new geometric model that have changed relative to the original geometric model, the names of the topological elements are set based on the original names; and for topological elements newly added in the new geometric model relative to the original geometric model, the names of the topological elements are set by adding element identifiers.

[0011] Furthermore, methods for assigning original names to the topological elements of the original geometric model based on sketches and feature generation methods include:

[0012] When a sketch is stretched, rotated, or swept to form the base features of the original geometric model, the original names of the topological elements in the base features are set by combining the sketch element naming information with the feature generation method.

[0013] When rounding or flattening corners on the base feature to form a decorative feature of the original geometric model, the original names of each topological element on the decorative feature are set according to the original names of the topological elements in the base feature.

[0014] Perform feature mirroring or array operations on the base features and modification features to form a composite feature of the original geometric model. Set the original names of each topological element on the composite feature according to the original names of the topological elements in the base features and modification features.

[0015] Furthermore, the original name is set to OpCode+FeatID:ElementType+ElementId; where OpCode is a sketch, feature, or operation identifier, FeatID is a feature ID number, ElementType is a topology element type identifier, and ElementId is a topology element ID number.

[0016] Furthermore, the first to third characters of the original name are set as sketch, feature, or operation identifiers; the fourth to sixth characters of the original name are set as feature ID numbers; the seventh character of the original name is set as a separator; the eighth character of the original name is set as a type identifier for the topology element; the ninth character of the original name is set as a type bit; and the tenth to twelfth characters of the original name ON are set as topology element ID numbers.

[0017] Furthermore, the type identifiers include faces, edges, and points, and are represented as f, e, and v, respectively, where f0, f1, f2, and f3 represent the default face, base face, top face, and side face, respectively; e1, e2, and e3 represent manifold edges, non-manifold edges, and dangling edges, respectively; and v1, v2, and v3 represent manifold points, non-manifold points, and isolated points, respectively.

[0018] Furthermore, when the topology element is a face element, the method for setting the reference name based on the original name of the topology element, local topology information, orientation information, and the named storage set includes:

[0019] Step A1-1: Denote the original name of the current topology element referencing face f as ON. * (f) will change the original name to ON * (f) Add the reference name RN to the topology element * (f) In the process of determining the original name ON * (f) Check if the name is unique in the named storage set. If it is unique, end the naming process; otherwise, go to step A1-2.

[0020] Step A1-2: Construct the set of original names of the adjacent faces of the topological element, AdjFaceONSet(f), and add it to the reference name RN. * In (f), determine whether the topological element has a symmetric active surface. If it does not exist, the naming ends; otherwise, jump to step A1-3.

[0021] Steps A1-3: Obtain the feature direction featDir of the symmetric active surface, then find the intersection edge between the symmetric active surface and the topological element, calculate the associated orientation information of the symmetric active surface, add the associated orientation information record to the associated orientation information set SymActFeatALSet(f), and add the associated orientation information set SymActFeatALSet(f) to the reference name RN. * (f) marks the end of the naming process.

[0022] Furthermore, the process of calculating the associated orientation information of the symmetric activation surface includes:

[0023] A sampling point is set on the intersection of the symmetric active surface and the topological element, and the tangential direction eVec of the sampling point along the topological direction of the intersection is calculated. The tangential direction eVec is multiplied by the feature direction featDir, and the result symbol Sign(eVec,featDir) is obtained. The result symbol Sign(eVec,featDir) is the auxiliary orientation information.

[0024] Furthermore, when the topological element is a face element, the method for identifying the unique identification result of the topological element of the new geometric model based on the reference name includes:

[0025] Step B1-1: Resolve the reference name RN of the current topology element. * The original name ON in (f) * (f) Obtain the original name and ON the original name of each topological element in the new geometric model. * (f) Construct a candidate face set CFset(f) for face elements that satisfy the subset relation; if the candidate face set CFset(f) is empty, the output recognition result is that the face referenced by the current topological element is deleted; if the candidate face set CFset(f) is not empty, jump to step B1-2.

[0026] Step B1-2. Continue resolving the reference name RN * The set of original names of adjacent faces in (f) AdjFaceONSet(f) is used to remove candidate faces from the set CFset(f) whose names match the reference name RN. * (f) The set of original names of adjacent faces AdjFaceONSet(f) does not satisfy the subset relationship of face elements; if the candidate face set CFset(f) is empty, the output recognition result is that the reference face does not exist, and the recognition ends; determine whether the face elements in the candidate face set CFset(f) have an attached orientation information set SymActFeatALSet(f). If the face elements in the candidate face set CFset(f) do not have an attached orientation information set SymActFeatALSet(f), output the face elements in the candidate face set CFset(f) as the recognition result; if the face elements in the candidate face set CFset(f) have an attached orientation information set SymActFeatALSet(f), jump to step B1-3;

[0027] Step B1-3. Continue resolving the reference name RN * The associated orientation information set SymActFeatALSet(f) in (f) is used to remove candidate face sets CFset(f) that match the reference name RN. *(f) The attached orientation information set SymActFeatALSet(f) does not satisfy the subset relationship of the face elements; if the candidate face set CFset(f) is empty, the output recognition result is that the reference face does not exist and the recognition ends; if the candidate face set CFset(f) is a non-empty set, the output face elements in the candidate face set CFset are the recognition result.

[0028] Furthermore, when the topological element is an edge element, the method for setting the reference name based on the original name of the topological element, local topological information, direction information, and the named storage set includes:

[0029] Step A2-1. Denote the original name of the current topological element referencing edge e as ON. * (e) will change the original name to ON * (e) Add the reference name RN to the current topology element * (e) In the process of determining the original name ON * (e) Check if the name is unique in the named storage set. If it is unique, end the naming process; otherwise, go to step A2-2.

[0030] Step A2-2. Construct the set of original names of the adjacent faces of the current topology element, AdjFaceONSet(e), and add it to the reference name RN. * In (e), determine whether the current topological element is on a symmetric active surface. If it is not on a symmetric active surface, the naming process ends; otherwise, proceed to step A2-3.

[0031] Step A2-3. Calculate the associated orientation information of the current topological element referencing edge e, add the associated orientation information to the associated orientation information set SymActFeatALoc(e), and add the associated orientation information set SymActFeatALoc(e) to the reference name RN. * In (e); determine whether the current topological element is a splitting edge. If the current topological element is a splitting edge, jump to step A2-4; otherwise, end the naming process.

[0032] Step A2-4. Obtain the edge information EdgeCutInfo(e) of the current topology element. The edge information includes the set of starting endpoint faces, the set of ending endpoint faces, and the range of geometric parameters. Add the edge information EdgeCutInfo(e) to the reference name RN. * (e) marks the end of the naming process.

[0033] Furthermore, when the topological element is an edge element, the method for identifying the unique identification result of the topological element of the new geometric model based on the reference name includes:

[0034] Step B2-1. Resolve the reference name RN of the current topology element. * The original name ON in (e)* (e) Obtain the original name and ON of each topological element in the new geometric model. * (e) The edge elements that satisfy the subset relation are constructed into a candidate face set CFset(e); if the candidate face set CFset(e) is an empty set, the output recognition result is that the face referenced by the current topological element is deleted; if the candidate face set CFset(e) is a non-empty set, jump to step B2-2.

[0035] Step B2-2. Continue resolving the reference name RN * (e) is the set of original names of adjacent faces, AdjFaceONSet(e). Candidate faces in the set CFset(e) that are related to the reference name RN are removed. * (e) The set of original names of adjacent faces AdjFaceONSet(e) does not satisfy the subset relation of edge elements; if the candidate face set CFset(e) is empty, the output recognition result is that the reference face does not exist, and the recognition ends; determine whether the edge elements in the candidate face set CFset(e) have an attached orientation information set SymActFeatALoc(e). If the edge elements in the candidate face set CFset(e) do not have an attached orientation information set SymActFeatALoc(e), output the edge elements in the candidate face set CFset(e) as the recognition result; if the edge elements in the candidate face set CFset have an attached orientation information set SymActFeatALSet(e), jump to step B2-3;

[0036] Step B2-3. Continue resolving the reference name RN * The associated orientation information set SymActFeatALoc(e) in (e) is used to remove candidate face sets CFset(e) that match the reference name RN. * (e) The attached orientation information set SymActFeatALoc(e) does not satisfy the subset relation edge elements; if the candidate face set CFset(e) is empty, the output recognition result is that the reference face does not exist, and the recognition ends; if the candidate face set CFset(e) is a non-empty set, it is determined whether the edge elements in the candidate face set CFset(e) have the dividing edge information EdgeCutInfo(e). When the edge elements in the candidate face set CFset(e) do not have the dividing edge information EdgeCutInfo(e), the output of the edge elements in the candidate face set CFset(e) is the recognition result; when the edge elements in the candidate face set CFset have the dividing edge information EdgeCutInfo(e), jump to step B2-4;

[0037] Step B2-4. Continue resolving the reference name RN * (e) contains the edge information EdgeCutInfo(e), and the candidate face set CFset(e) is removed if it matches the reference name RN.* (e) The edge information EdgeCutInfo(e) does not satisfy the subset relationship; if the candidate face set CFset(e) is empty, the output recognition result is that the reference face does not exist and the recognition ends; if the candidate face set CFset(e) is a non-empty set, the face elements in the candidate face set CFset are output as the recognition result.

[0038] Furthermore, when the topological element is a point element, the method for setting the reference name based on the original name of the topological element, local topological information, direction information, and the named storage set includes:

[0039] Step A3-1. Record the original name of the current topology element reference point v as ON. * (v) will change the original name to ON * (v) Add the reference name RN to the current topology element. * (v) In; Determine the original name ON * (v) Check if the name is unique in the named storage set. If it is unique, end the naming process; otherwise, go to step A3-2.

[0040] Step A3-2. Construct the set of primitive names of the adjacent faces of the current topology element, AdjFaceONSet(v), and add it to the reference name RN. * In step (v), determine if there is a primary edge among the adjacent edges of the referencing point v. If there is a primary edge, the process ends and jumps to step A3-3; otherwise, the process ends and jumps to step A3-4.

[0041] Step A3-3. Obtain the native edge information adjacent to the reference point v, add the native edge information to the native edge information set InhEdgeInfoSet(v), and add the native edge information set InhEdgeInfoSet(v) to the reference name RN. * (v) End of naming;

[0042] Step A3-4. Construct a set of reference names AdjEdgeRNSet(v) for all edge elements adjacent to the reference point v, add the set of reference names AdjEdgeRNSet(v) to the reference name RN(v), and the naming is complete.

[0043] Furthermore, when the topological element is a point element, methods for identifying the unique recognition result of the topological element of the new geometric model based on the reference name include:

[0044] Step B3-1. Resolve the reference name RN of the current topology element. * (v) The original name ON * (v) Iterate through the topological elements in the new geometric model to obtain the original names and ON the original names. *(v) Point elements that satisfy the subset relation are constructed into a candidate face set CFset(v); if the candidate face set CFset(v) is an empty set, the output recognition result is that the face referenced by the current topological element is deleted; if the candidate face set CFset(v) is a non-empty set, jump to step B3-2.

[0045] Step B3-2. Continue resolving the reference name RN * The set of original names of adjacent faces in (v) AdjFaceONSet(v) is used to remove candidate faces from the set CFset(v) whose reference name RN is the same as the original name. * The set of original names of adjacent faces AdjFaceONSet(v) does not satisfy the subset relation for point elements; if the candidate face set CFset(v) is empty, the output recognition result is that the reference face does not exist, and the recognition ends;

[0046] Determine whether the vertex elements in the candidate face set CFset(v) contain the original edge information set InhEdgeInfoSet(v). If the vertex elements in the candidate face set CFset contain the original edge information set InhEdgeInfoSet(v), proceed to step B3-3; if the vertex elements in the candidate face set CFset(v) do not contain the original edge information set InhEdgeInfoSet(v), proceed to step B3-4.

[0047] Step B3-3. Continue resolving the reference name RN * The original edge information set InhEdgeInfoSet(v) in (v) is used to remove candidate face sets CFset(v) that match the reference name RN. * The original edge information set InhEdgeInfoSet(v) does not satisfy the subset relation for the point elements; if the candidate face set CFset(v) is empty, the output recognition result is that the reference face does not exist, and the recognition ends; if the candidate face set CFset(v) is a non-empty set, the output of the point elements in the candidate face set CFset(v) is the recognition result.

[0048] Step B3-4. Continue resolving the reference name RN * The reference name set AdjEdgeRNSet(v) in (v) is used to remove candidate faces from the face set CFset(v) that match the reference name RN. * The reference name set AdjEdgeRNSet(v) does not satisfy the subset relationship of point elements; if the candidate face set CFset(v) is empty, the output recognition result is that the reference face does not exist and the recognition ends; if the candidate face set CFset(v) is a non-empty set, the output of the point elements in the candidate face set CFset(e) is the recognition result.

[0049] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0050] This invention sets reference names for topological elements when they reference the original geometric model in a new geometric model. Reference names are set based on the original name, local topological information, and orientation information of face elements, as well as a named storage set; reference names are set based on the original name, local topological information, orientation information, and geometric parameters of edge elements, as well as a named storage set; and reference names are set based on the original name, local topological information, orientation information, and information of adjacent edges of point elements, as well as a named storage set. Based on the reference names, the topological elements of the new geometric model are identified to obtain a unique identification result. This invention utilizes effective information from the design process to hierarchically design element reference names, allowing for the addition of more layers of information to assist in recording and identification on the basis of the existing reference name expression structure. It also provides a step-by-step identification mechanism to eliminate reference ambiguity, facilitating data consistency maintenance. Attached Figure Description

[0051] Figure 1 This is an example diagram illustrating the naming problem of topology elements provided in the implementation embodiment;

[0052] Figure 2 This is an example diagram of original name design based on sketches and feature generation methods provided in the embodiment;

[0053] Figure 3 This is a schematic diagram of feature orientation information provided in the design process of the embodiment;

[0054] Figure 4 This is a schematic diagram of local topology information provided in the design process of the embodiment;

[0055] Figure 5 This is a schematic diagram of edge direction information provided in the design process of the embodiment;

[0056] Figure 6 This is provided in the embodiment. Figure 4 A schematic diagram showing the geometric parameters of the mid-section surface;

[0057] Figure 7 These are example diagrams of the activated surface and the symmetrical activated surface provided in the embodiments;

[0058] Figure 8 This is an example diagram illustrating the design and identification of face element reference names provided in the implementation embodiment;

[0059] Figure 9 This is an example diagram illustrating the design and identification of edge element reference names provided in the implementation embodiment;

[0060] Figure 10 This is an example diagram of point element reference name design and identification provided in the implementation embodiment. Detailed Implementation

[0061] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0062] like Figure 1 As shown, the topology element naming problem is mainly used to solve the element differentiation problem during model construction and the element matching problem during model reconstruction after design modifications. The differentiation problem is due to ambiguity caused by the same original name of elements. In the example, e1 and e2 have the same original name, and it is impossible to effectively distinguish between the two edges when referencing them. The matching problem is because the old referenced elements have changed in the reconstructed model, and it is necessary to identify new elements that conform to the user's design intent, which may be one, multiple, or even non-existent.

[0063] This implementation provides an emotion recognition method based on a multi-branch fusion attention mechanism, including:

[0064] Methods for assigning original names to topological elements of the original geometric model based on sketches and feature generation include:

[0065] When a sketch is stretched, rotated, or swept to form the base features of the original geometric model, the original names of the topological elements in the base features are set by combining the sketch element naming information with the feature generation method.

[0066] When rounding or flattening corners on the base feature to form a decorative feature of the original geometric model, the original names of each topological element on the decorative feature are set according to the original names of the topological elements in the base feature.

[0067] Perform feature mirroring or array operations on the base features and modification features to form a composite feature of the original geometric model. Set the original names of each topological element on the composite feature according to the original names of the topological elements in the base features and modification features.

[0068] The original name is set to OpCode+FeatID:ElementType+ElementId; where OpCode is the sketch, feature, or operation identifier, FeatID is the feature ID number, ElementType is the type identifier of the topology element, and ElementId is the topology element ID number. The first to third characters of the original name are set to the sketch, feature, or operation identifier; the fourth to sixth characters are set to the feature ID number; the seventh character is set to the separator; the eighth character is set to the type identifier of the topology element; the ninth character is set to the type field; and the tenth to twelfth characters of the original name are set to the topology element ID number.

[0069] The type identifiers include faces, edges, and points, and are represented as f, e, and v, respectively. f0, f1, f2, and f3 represent the default face, base face, top face, and side face, respectively; e1, e2, and e3 represent manifold edges, non-manifold edges, and dangling edges, respectively; and v1, v2, and v3 represent manifold points, non-manifold points, and isolated points, respectively.

[0070] like Figure 2 As shown, the sketch information and the generation methods of various features are inherent information in the parametric modeling process. Designing original names based on this inherent information is stable and will not be confused due to feature reconstruction. In the example, the base feature is created by extruding the sketch. The base face elements in the base feature directly inherit the element names from the sketch. The naming convention for the remaining point, edge, and face elements in the base is as follows:

[0071] ① Face Elements: The top face name consists of the base face combined with the feature identifier and the element type identifier, while the side face name consists of the edge on the base face combined with the feature identifier and the element type identifier. In the example, ftop and fside represent the top face and the side face, respectively, ETU is the extrusion feature identifier, and f, e, and v are the element type identifiers.

[0072] ② Edge elements: The top edge name consists of the edge on the base surface combined with the feature identifier and the element type identifier, while the side edge name consists of the point on the base surface combined with the feature identifier and the element type identifier. In the example, etop and eside represent the top edge and the side edge, respectively.

[0073] ③ Point elements: The naming of points on the top surface is composed of points on the base surface combined with feature identifiers and element type identifiers. In the example, vtop represents a point on the top surface.

[0074] like Figures 3 to 6 As shown, the information that can be effectively utilized in the process of designing reference names mainly includes feature direction information, local topological information, element direction information, and geometric parameter domain information. These information depend on entities or features and are also intrinsic information in the design process, which can be used relatively stably for element differentiation and matching.

[0075] Feature orientation information is inherent information dependent on the feature generation method. The main feature orientation information includes sweep direction, stretching direction, and rotation direction (rotation direction and rotation axis direction), as follows: Figure 3 Using characteristic directions effectively to distinguish elements is highly efficient.

[0076] The differences in local topological information of topological elements can effectively distinguish different elements, and the local topological information of elements has a certain stability during continuous design changes and modifications, which is very important for element matching after model reconstruction. Figure 4This is an example of utilizing local topology information. f1 and f2 are dividing faces with the same original name. The set of original names of the adjacent faces of f1 is AdjFaceONSet(f1) = {ON(fb), ON(f6), ON(f5), ON(f3)}, and the set of original names of the adjacent faces of f2 is AdjFaceONSet(f2) = {ON(fb), ON(f6), ON(f5), ON(f4)}. The original names of the adjacent face f3 of f1 and the adjacent face f4 of f2 are different, so they can be distinguished.

[0077] Topological element orientation information mainly refers to the orientation of face normals and edges. Face normals primarily refer to the outward normals of topological faces in the boundary model. Edge orientations have two types: one is the topological orientation, where the topological edges have opposite directions between two adjacent faces, so the topological face on which they depend must be clearly defined when using the topological orientation of an edge; the other is the geometric parameter orientation, which is the direction of change of parameters in the geometric representation of the edge, such as... Figure 5 As shown. The geometric parameters of an edge are effective for determining its start and end points, provided that the edge element can be uniquely identified and recorded.

[0078] The geometric parameter domain information of topological elements is of great guiding significance for distinguishing the segmented elements. This is because the geometric representation of topological edges and surfaces in feature modeling systems is generally NURBS curves and surfaces, and the geometric representation of the parametric curves and parametric surfaces of edge and surface elements remains unchanged after segmentation. Figure 6 Only the domain of the parameters changes. Therefore, although the topological information of each segmented sub-element changes, there is still a geometric discontinuity between them.

[0079] Each topology element is assigned an original name to construct a named storage collection. The specific design is as follows:

[0080] i) Store the collection ElementMap;

[0081] ADT <elementmap>{Name: Original name (ON); Type: Element type (Face\Edge\Vertex); Index: Access index of this element in the current topology entity}ADT <elementmap>

[0082] ii) Abstract named entity class TopoBrepShape

[0083] ADT <topobrepshape>{Data object D: ElementMap instance tripleMap; Topological entity object featShape; Data relationship R: tripleMap is the naming information attached to the featShape entity; Basic operations P: Query, access, and modification methods related to entity information} ADT <topobrepshape>

[0084] After feature editing on the original geometric model, a new geometric model is formed. Topological elements in the new geometric model that are consistent with the original geometric model are referenced through a mapping of their original names; that is, elements retained from the old geometric model are transferred to the new geometric model. By traversing the point, edge, and face elements directly retained from the old geometric model in the new geometric model, the original names of these elements in the old geometric model are directly mapped to their corresponding names in the new geometric model, thus completing the naming mapping of invariant elements.

[0085] For topological elements in the new geometric model that have changed relative to the original geometric model, reference names are established through name passing using their original names; that is, elements that have been split or merged from the old geometric model into the new geometric model. By traversing the elements in the new geometric model that originated from edge or face splitting or merging in the old geometric model, the original names of the elements in the old geometric model are directly or in combination passed to the corresponding elements in the new model, thus completing the naming transfer of the changed elements. Specifically, during splitting, the original name of the split element in the old geometric model is directly passed to the split element in the new geometric model; during merging, the original names of the merged elements in the old geometric model are combined and passed to the merged element in the new geometric model; when an element disappears, since the element does not exist in the new geometric model, its original name is not inherited.

[0086] For new topological elements added to the new geometric model relative to the original geometric model, reference names are established using new element identifiers. During Boolean operations between feature bodies and entities in the old geometric model, face elements originate from feature faces and are not newly generated, but edge and vertex elements are newly generated. These newly generated edge and vertex elements do not depend on elements in the old geometric model, and their generation process does not rely on stable feature information; therefore, they can only be directly assigned the same original name according to their element type. To distinguish these newly generated elements, their reference names are recorded when they are referenced to uniquely identify them. After the naming mapping of invariant elements and the naming propagation of variable elements, naming newly generated elements only requires traversing the unnamed elements in the new geometric model and then completing the naming according to the user-defined new element identifier scheme.

[0087] In order to standardize and describe the hierarchical design and identification principle mechanism in detail, the following explanations are introduced in this embodiment:

[0088] A reference name is a unique identifier designed to rely on the topological or geometric information of a face element when it is referenced, denoted as RN(RealName). The concept of reference names for edges and points described below is consistent with this.

[0089] Original elements refer to point, edge, and surface elements that are directly generated from original features.

[0090] Activation surfaces and activation features refer to the surfaces that cause changes in the topological structure of elements, which are called activation surfaces, and the features corresponding to activation surfaces are called activation features.

[0091] Symmetrical activation surfaces and symmetrical activation features refer to the presence of two or more surfaces with the same original name in the adjacent surfaces of an activation surface. The features corresponding to symmetrical activation surfaces are called symmetrical activation features.

[0092] The subset relation principle states that: Let A and B be two sets of certain recorded information. If A and B satisfy... or Then A and B are said to satisfy a subset relationship. Modifying the feature model causes it to continuously change from one state to another. During this continuous change, if the sets of adjacent elements of the referenced element are classified according to certain characteristics, it can be found that the sets of adjacent elements of the matching elements that meet the design intent during identification often satisfy a subset relationship under a certain type. This invention divides the sets of adjacent faces of topological elements into two types: active face sets and inactive face sets, and determines whether a subset relationship exists during identification based on these types.

[0093] like Figure 7 As shown, activation surfaces cause changes in the topological structure of elements. A symmetric activation surface has two or more surfaces with the same original name in its adjacent face set; therefore, a symmetric activation surface is always an activation surface. The features corresponding to activation surfaces are called activation features, and the features corresponding to symmetric activation surfaces are called symmetric activation features.

[0094] When a topological element in a new geometric model references an element in the original geometric model, the reference name of the topological element is set. When the topological element is a face element, the methods for setting the reference name based on the original name of the topological element, local topological information, orientation information, and the named storage set include:

[0095] Step A1-1: Denote the original name of the current topology element referencing face f as ON. * (f) will change the original name to ON * (f) Add the reference name RN to the topology element * (f) In the condition that the original name ON is determined; * (f) Check if the name is unique in the named storage set. If it is unique, end the naming process; otherwise, go to step A1-2.

[0096] Step A1-2: Construct the set of original names of the adjacent faces of the topological element, AdjFaceONSet(f), and add it to the reference name RN. * In (f), determine whether the topological element has a symmetric active surface. If it does not exist, the naming ends; otherwise, jump to step A1-3.

[0097] Steps A1-3: Obtain the feature direction featDir of the symmetric active surface, then find the intersection edge between the symmetric active surface and the topological element, calculate the associated orientation information of the symmetric active surface, add the associated orientation information record to the associated orientation information set SymActFeatALSet(f), and add the associated orientation information set SymActFeatALSet(f) to the reference name RN. * (f) marks the end of the naming process.

[0098] The process of calculating the associated orientation information of the symmetric activation surface includes:

[0099] A sampling point is set on the intersection of the symmetric active surface and the topological element, and the tangential direction eVec of the sampling point along the topological direction of the intersection is calculated. The tangential direction eVec is multiplied by the feature direction featDir, and the result symbol Sign(eVec,featDir) is obtained. The result symbol Sign(eVec,featDir) is the auxiliary orientation information.

[0100] When the topological element is a face element, methods for identifying the unique identification result of the topological element of the new geometric model based on the reference name include:

[0101] Step B1-1: Resolve the reference name RN of the current topology element. * The original name ON in (f) * (f) Obtain the original name and ON the original name of each topological element in the new geometric model. * (f) Construct a candidate face set CFset(f) for face elements that satisfy the subset relation; if the candidate face set CFset(f) is empty, the output recognition result is that the face referenced by the current topological element is deleted; if the candidate face set CFset(f) is not empty, jump to step B1-2.

[0102] Step B1-2. Continue resolving the reference name RN * The set of original names of adjacent faces in (f) AdjFaceONSet(f) is used to remove candidate faces from the set CFset(f) whose names match the reference name RN. * (f) The set of original names of adjacent faces AdjFaceONSet(f) does not satisfy the subset relationship of face elements; if the candidate face set CFset(f) is empty, the output recognition result is that the reference face does not exist, and the recognition ends; determine whether the face elements in the candidate face set CFset(f) have an attached orientation information set SymActFeatALSet(f). If the face elements in the candidate face set CFset(f) do not have an attached orientation information set SymActFeatALSet(f), output the face elements in the candidate face set CFset(f) as the recognition result; if the face elements in the candidate face set CFset(f) have an attached orientation information set SymActFeatALSet(f), jump to step B1-3;

[0103] Step B1-3. Continue resolving the reference name RN * The associated orientation information set SymActFeatALSet(f) in (f) is used to remove candidate face sets CFset(f) that match the reference name RN. * (f) The attached orientation information set SymActFeatALSet(f) does not satisfy the subset relationship of the face elements; if the candidate face set CFset(f) is empty, the output recognition result is that the reference face does not exist and the recognition ends; if the candidate face set CFset(f) is a non-empty set, the output face elements in the candidate face set CFset are the recognition result.

[0104] When the topological element is an edge element, the methods for setting the reference name based on the original name of the topological element, local topological information, direction information, and the named storage set include:

[0105] Step A2-1. Denote the original name of the current topological element referencing edge e as ON. * (e) will change the original name to ON * (e) Add the reference name RN to the current topology element * (e) In the process of determining the original name ON * (e) Check if the name is unique in the named storage set. If it is unique, end the naming process; otherwise, go to step A2-2.

[0106] Step A2-2. Construct the set of original names of the adjacent faces of the current topology element, AdjFaceONSet(e), and add it to the reference name RN. * In (e), determine whether the current topological element is on a symmetric active surface. If it is not on a symmetric active surface, the naming process ends; otherwise, proceed to step A2-3.

[0107] Step A2-3. Calculate the associated orientation information of the current topological element referencing edge e, add the associated orientation information to the associated orientation information set SymActFeatALoc(e), and add the associated orientation information set SymActFeatALoc(e) to the reference name RN. * In (e); determine whether the current topological element is a splitting edge. If the current topological element is a splitting edge, jump to step A2-4; otherwise, end the naming process.

[0108] Step A2-4. Obtain the edge information EdgeCutInfo(e) of the current topology element. The edge information includes the set of starting endpoint faces, the set of ending endpoint faces, and the range of geometric parameters. Add the edge information EdgeCutInfo(e) to the reference name RN. * (e) marks the end of the naming process.

[0109] When a topological element is an edge element, methods for identifying unique recognition results based on the reference name of the topological elements in the new geometric model include:

[0110] Step B2-1. Resolve the reference name RN of the current topology element. * The original name ON in (e) * (e) Obtain the original name and ON of each topological element in the new geometric model. * (e) The edge elements that satisfy the subset relation are constructed into a candidate face set CFset(e); if the candidate face set CFset(e) is an empty set, the output recognition result is that the face referenced by the current topological element is deleted; if the candidate face set CFset(e) is a non-empty set, jump to step B2-2.

[0111] Step B2-2. Continue resolving the reference name RN * (e) is the set of original names of adjacent faces, AdjFaceONSet(e). Candidate faces in the set CFset(e) that are related to the reference name RN are removed. * (e) The set of original names of adjacent faces AdjFaceONSet(e) does not satisfy the subset relation of edge elements; if the candidate face set CFset(e) is empty, the output recognition result is that the reference face does not exist, and the recognition ends; determine whether the edge elements in the candidate face set CFset(e) have an attached orientation information set SymActFeatALoc(e). If the edge elements in the candidate face set CFset(e) do not have an attached orientation information set SymActFeatALoc(e), output the edge elements in the candidate face set CFset(e) as the recognition result; if the edge elements in the candidate face set CFset have an attached orientation information set SymActFeatALSet(e), jump to step B2-3;

[0112] Step B2-3. Continue resolving the reference name RN * The associated orientation information set SymActFeatALoc(e) in (e) is used to remove candidate face sets CFset(e) that match the reference name RN. * (e) The attached orientation information set SymActFeatALoc(e) does not satisfy the subset relation edge elements; if the candidate face set CFset(e) is empty, the output recognition result is that the reference face does not exist, and the recognition ends; if the candidate face set CFset(e) is a non-empty set, it is determined whether the edge elements in the candidate face set CFset(e) have the dividing edge information EdgeCutInfo(e). When the edge elements in the candidate face set CFset(e) do not have the dividing edge information EdgeCutInfo(e), the output of the edge elements in the candidate face set CFset(e) is the recognition result; when the edge elements in the candidate face set CFset have the dividing edge information EdgeCutInfo(e), jump to step B2-4;

[0113] Step B2-4. Continue resolving the reference name RN * (e) contains the edge information EdgeCutInfo(e), and the candidate face set CFset(e) is removed if it matches the reference name RN. * (e) The edge information EdgeCutInfo(e) does not satisfy the subset relationship; if the candidate face set CFset(e) is empty, the output recognition result is that the reference face does not exist and the recognition ends; if the candidate face set CFset(e) is a non-empty set, the face elements in the candidate face set CFset are output as the recognition result.

[0114] When the topological element is a point element, the methods for setting the reference name based on the original name of the topological element, local topological information, direction information, and the named storage set include:

[0115] Step A3-1. Record the original name of the current topology element reference point v as ON. * (v) will change the original name to ON * (v) Add the reference name RN to the current topology element. * (v) In; Determine the original name ON * (v) Check if the name is unique in the named storage set. If it is unique, end the naming process; otherwise, go to step A3-2.

[0116] Step A3-2. Construct the set of primitive names of the adjacent faces of the current topology element, AdjFaceONSet(v), and add it to the reference name RN. * In step (v), determine if there is a primary edge among the adjacent edges of the referencing point v. If there is a primary edge, the process ends and jumps to step A3-3; otherwise, the process ends and jumps to step A3-4.

[0117] Step A3-3. Obtain the native edge information adjacent to the reference point v, add the native edge information to the native edge information set InhEdgeInfoSet(v), and add the native edge information set InhEdgeInfoSet(v) to the reference name RN. * (v) End of naming;

[0118] Step A3-4. Construct a set of reference names AdjEdgeRNSet(v) for all edge elements adjacent to the reference point v, add the set of reference names AdjEdgeRNSet(v) to the reference name RN(v), and the naming is complete.

[0119] When the topological element is a point element, methods for identifying the unique identification result of the topological element of the new geometric model based on the reference name include:

[0120] Step B3-1. Resolve the reference name RN of the current topology element. * (v) The original name ON * (v) Iterate through the topological elements in the new geometric model to obtain the original names and ON the original names. * (v) Point elements that satisfy the subset relation are constructed into a candidate face set CFset(v); if the candidate face set CFset(v) is an empty set, the output recognition result is that the face referenced by the current topological element is deleted; if the candidate face set CFset(v) is a non-empty set, jump to step B3-2.

[0121] Step B3-2. Continue resolving the reference name RN * The set of original names of adjacent faces in (v) AdjFaceONSet(v) is used to remove candidate faces from the set CFset(v) whose reference name RN is the same as the original name. * The set of original names of adjacent faces AdjFaceONSet(v) does not satisfy the subset relation for point elements; if the candidate face set CFset(v) is empty, the output recognition result is that the reference face does not exist, and the recognition ends;

[0122] Determine whether the vertex elements in the candidate face set CFset(v) contain the original edge information set InhEdgeInfoSet(v). If the vertex elements in the candidate face set CFset contain the original edge information set InhEdgeInfoSet(v), proceed to step B3-3; if the vertex elements in the candidate face set CFset(v) do not contain the original edge information set InhEdgeInfoSet(v), proceed to step B3-4.

[0123] Step B3-3. Continue resolving the reference name RN * The original edge information set InhEdgeInfoSet(v) in (v) is used to remove candidate face sets CFset(v) that match the reference name RN. * The original edge information set InhEdgeInfoSet(v) does not satisfy the subset relation for the point elements; if the candidate face set CFset(v) is empty, the output recognition result is that the reference face does not exist, and the recognition ends; if the candidate face set CFset(v) is a non-empty set, the output of the point elements in the candidate face set CFset(v) is the recognition result.

[0124] Step B3-4. Continue resolving the reference name RN * The reference name set AdjEdgeRNSet(v) in (v) is used to remove candidate faces from the face set CFset(v) that match the reference name RN. * The reference name set AdjEdgeRNSet(v) does not satisfy the subset relationship of point elements; if the candidate face set CFset(v) is empty, the output recognition result is that the reference face does not exist and the recognition ends; if the candidate face set CFset(v) is a non-empty set, the output of the point elements in the candidate face set CFset(e) is the recognition result.

[0125] The following is combined Figures 8 to 10 The provided FaceModel, EdgeModel, and VetexModel methods for hierarchical design and identification of element reference names in the embodiments are described in detail.

[0126] 1. Let face f1 be referenced in the FaceModel. The specific process of face naming and face identification is as follows:

[0127] 1-1 Naming. Add the original name information ON(f1); since ON(f1) = ON(f2), construct the set of original names of adjacent faces of f1, AdjFaceONSet(f1) = {ASet(f1), BSet(f1)}, where ASet(f1) = {ON(fb)} is the set of active faces and BSet(f1) = {ON(f3), ON(f4), ON(f5)} is the set of inactive faces; the reference face f1 has a symmetric active face fb, add the associated orientation information SymActFeatALSet(f1) = {<ECU001,->}, naming ends. Finally, RN(f1) = {ON(f1); {{ON(fb)}, {ON(f3), ON(f4), ON(f5)}}; {<ECU001,->}}.

[0128] 1-2 Face Identification. Parse reference name RN for ON = ON(f1), construct candidate face set CFset as {f1, f2}. Parse reference name RN for AdjFaceONSet = {{ON(fb)}, {ON(f3), ON(f4), ON(f5)}}. The active face set of candidate faces in the candidate face set CFSet satisfies subset relations with {ON(fb)}, and the inactive face set satisfies subset relations with {ON(f3), ON(f4), ON(f5)}. Parse reference name RN for SymActFeatALSet = {<ECU001,->}, calculate the associated orientation information of f1 and f2 in the candidate face set CFset as follows:<ECU001,-> and<ECU001,+> Therefore, f2 is eliminated. The final candidate face set CFset = {f1} contains only one candidate face f1, so f1 is returned.

[0129] 2. Let e1 be the reference edge in the EdgeModel. The specific process of edge naming and edge identification is as follows:

[0130] 2-1 Edge Naming. Add original name information ON(e1); ON(e1) = ON(e2) = ON(e3) = ON(e4), so it is not unique. Add the set of original names of adjacent faces of the reference edge e1, AdjFaceONSet(e1) = {{ON(fb)}, {ON(f1)}}; There is a symmetric active face fb, add the attached orientation information SymActFeatALoc(e1) = {<ECU001,-> Since the referenced edge e1 is a splitting edge, add the splitting edge information EdgeCutInfo(e1) = {{{ON(f5)}, {ON(fc)},<u1,u2>}},in<u1,u2> The range of geometric parameters for e1 is defined here, ending the naming convention. The final edge name is:

[0131] RN(e1)={ON(e1);{{ON(fb)},{ON(f1)}};{<ECU001,->};{{ON(f5)},{ON(fc)},<u1,u2>}}.

[0132] 2-2 Edge Identification. Parse the reference name RN for ON = ON(e1), constructing the candidate edge set CESet as {e1,e2,e3,e4}; parse the reference name RN for AdjFaceONSet = {{ON(fb)},{ON(f1)}}, where the adjacent face sets of all candidate edges in CESet are the same as those in AdjFaceONSet; parse the reference name RN for SymActFeatALoc =<ECU001,-> Calculate the associated azimuth information of e1, e2, e3, and e4 in CFset as follows:<ECU001,-> ,<ECU001,+> ,<ECU001,+> ,<ECU001,-> Therefore, e2 and e3 are removed; the geometric parameter information EdgeCutInfo in the parsed reference name RN is resolved to {{ON(f5)}, {ON(fc)}.<u1,u2>}, and EdgeCutInfo(e4)={{ON(fc)},{ON(f5)},<u3,u4>},in<u3,u4> Since the geometric parameters of e4 are within the range, e4 is discarded. The final candidate edge set CEset = {e1} contains only one candidate edge e1, so e1 is returned.

[0133] 3. Let v1 be the reference point in the model VetexModel. The specific process of point naming and point identification is as follows:

[0134] 3-1 Naming. Add the original name information ON(v1); ON(v1) = ON(v2), so it is not unique. Add the original name set of the adjacent edges of the referencing point v, AdjEdgeONSet(v) = {ON(e1), ON(e2), ON(e3)}; e1 is the source edge, add it to the InhEdgeInfoSet(v) of the referencing point v = {<RN(e1),end>}, naming ends. Therefore, RN(v1) = {ON(v1); {ON(e1),ON(e2),ON(e3)}; {<RN(e1),end>}}.

[0135] 3-2 Point Identification. Parse the reference name RN: ON = ON(v1), construct the candidate point set CVset as {v1, v2}; parse the reference name RN: AdjEdgeONSet = {ON(e1), ON(e2), ON(e3)}, the adjacent edge sets of the candidate points in CVset all satisfy the subset relationship principle with AdjEdgeONSet; parse the reference name RN: InhEdgeInfoSet = {<RN(e1),end> The original edge information of candidate points v1 and v2 in CVset are as follows:<RN(e1),end> ,<RN(e1),start> Since the source edge information of v2 does not satisfy the subset relationship with the InhEdgeInfoSet information, candidate point v2 is removed. The final candidate point set CVset = {v1} contains only one candidate point v1, so v1 is returned.

[0136] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0137] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0138] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0139] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0140] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.< / topobrepshape> < / topobrepshape> < / elementmap> < / elementmap>

Claims

1. A method for maintaining the feature validity based on topological element naming, characterized in that, include: Based on the sketch and feature generation method, the original names are set for the topological elements of the original geometric model, and the original names of each topological element are used to construct a named storage set. When a topological element in a new geometric model references a topological element in the original geometric model, the reference name of the topological element is set; When the topology element is a face element, the reference name is set based on the original name of the topology element, local topology information, orientation information, and the named storage set, specifically including: Step A1-1: Denote the original name of the current topological element referencing face f as... , the original name Add the reference name to the topology element In Chinese; determine the original name If the naming is unique in the named storage set, then end the naming process; otherwise, proceed to step A1-2. Step A1-2: Construct the set of original names of the adjacent faces of the topological element, AdjFaceONSet(f), and add it to the reference name. In the middle; determine whether the topological element has a symmetric active surface. If not, the naming ends; otherwise, jump to step A1-3. Step A1-3: Obtain the feature direction featDir of the symmetric active surface, then find the intersection edge between the symmetric active surface and the topological element, calculate the associated orientation information of the symmetric active surface, add the associated orientation information record to the associated orientation information set SymActFeatALSet(f), and add the associated orientation information set SymActFeatALSet(f) to the reference name. The naming process ends here. When a topological element is an edge element, the reference name is set based on the original name of the topological element, local topological information, direction information, and the named storage set, specifically including: Step A2-1. Denote the original name of the current topological element referencing edge e as: , the original name Add the reference name to the current topology element In Chinese; determine the original name If the naming is unique in the named storage set, then end the naming process; otherwise, proceed to step A2-2. Step A2-2. Construct the set of original names of the adjacent faces of the current topology element, AdjFaceONSet(e), and add it to the reference name. In the middle; determine whether the current topological element is on a symmetric active surface. If it is not on a symmetric active surface, the naming ends; otherwise, jump to step A2-3. Step A2-3. Calculate the associated orientation information of the current topological element referencing edge e, add the associated orientation information to the associated orientation information set SymActFeatALoc(e), and add the associated orientation information set SymActFeatALoc(e) to the reference name. In the middle; determine whether the current topological element is a splitting edge. If the current topological element is a splitting edge, jump to step A2-4; otherwise, end the naming process. Step A2-4. Obtain the edge information EdgeCutInfo(e) of the current topology element. The edge information includes the set of starting endpoint faces, the set of ending endpoint faces, and the range of geometric parameters. Add the edge information EdgeCutInfo(e) to the reference name. The naming process ends here. When the topological element is a point element, the reference name is set based on the original name of the topological element, local topological information, direction information, and the named storage set, specifically including: Step A3-1. Record the original name of the current topological element reference point v as... , the original name Add the reference name to the current topology element In Chinese; determine the original name If the naming is unique in the named storage set, then end the naming process; otherwise, proceed to step A3-2. Step A3-2. Construct the set of primitive names of the adjacent faces of the current topology element, AdjFaceONSet(v), and add it to the reference name. In the middle; determine whether there is a primary edge among the adjacent edges of the reference point v. If there is a primary edge among the adjacent edges of the reference point v, then the process ends and jumps to step A3-3. If there is no primary edge among the adjacent edges of the reference point v, then the process ends and jumps to step A3-4. Step A3-3. Obtain the primary edge information adjacent to the reference point v, add the primary edge information to the primary edge information set InhEdgeInfoSet(v), and add the primary edge information set InhEdgeInfoSet(v) to the reference name. Middle; End of naming; Step A3-4. Construct a set of reference names AdjEdgeRNSet(v) for all edge elements adjacent to the reference point v, add the set of reference names AdjEdgeRNSet(v) to the reference name RN(v), and the naming is complete; The topological elements of the new geometric model are identified based on their reference names to obtain unique identification results.

2. The feature validity maintenance method according to claim 1, characterized in that, Methods for assigning original names to topological elements of the original geometric model based on sketches and feature generation include: When a sketch is stretched, rotated, or swept to form the base features of the original geometric model, the original names of the topological elements in the base features are set by combining the sketch element naming information with the feature generation method. When rounding or flattening corners on the base feature to form a decorative feature of the original geometric model, the original names of each topological element on the decorative feature are set according to the original names of the topological elements in the base feature. Perform feature mirroring or array operations on the base features and modification features to form a composite feature of the original geometric model. Set the original names of each topological element on the composite feature according to the original names of the topological elements in the base features and modification features.

3. The feature validity maintenance method according to claim 1, characterized in that, The original name is set as OpCode + FeatID:ElementType +ElementId; where OpCode is the sketch, feature, or operation identifier, FeatID is the feature ID number, ElementType is the type identifier of the topology element, and ElementId is the topology element ID number.

4. The feature validity maintenance method according to claim 3, characterized in that, The type identifiers include faces, edges, and points, and are represented as f, e, and v, respectively. f0, f1, f2, and f3 represent the default face, base face, top face, and side face, respectively; e1, e2, and e3 represent manifold edges, non-manifold edges, and dangling edges, respectively; and v1, v2, and v3 represent manifold points, non-manifold points, and isolated points, respectively.

5. The feature validity maintenance method according to claim 4, characterized in that, When the topological element is a face element, methods for identifying the unique identification result of the topological element of the new geometric model based on the reference name include: Step B1-1: Resolve the reference name of the current topology element. The original name in Obtain the original name and original name of each topological element in the new geometric model. The face elements that satisfy the subset relation are used to construct a candidate face set. If the candidate face set If the set is empty, the output recognition result is that the referenced face of the current topological element has been deleted; if the candidate face set is empty... If the set is non-empty, proceed to step B1-2; Step B1-2. Continue resolving reference names The set of original names of adjacent faces in the dataset AdjFaceONSet(f) is used to remove candidate faces. In and reference name The set of original names of adjacent faces, AdjFaceONSet(f), does not satisfy the subset relation for face elements; if the candidate face set... If empty, the output recognition result is "referenced face does not exist," and the recognition ends; determine the candidate face set. Does the face element contain an associated orientation information set SymActFeatALSet(f)? When the candidate face set... The face elements do not have an associated orientation information set SymActFeatALSet(f), so the candidate face set is output. The inner face elements are output as the recognition result; when the candidate face set The inner face elements have an attached orientation information set SymActFeatALSet(f), jump to step B1-3; Step B1-3. Continue resolving reference names The associated orientation information set SymActFeatALSet(f) is used to eliminate candidate face sets. In and reference name The subset of orientation information set SymActFeatALSet(f) does not satisfy the subset relation for face elements; if the candidate face set If the result is empty, the output will indicate that the referenced face does not exist, and the identification process will end; if the candidate face set is empty... Given a non-empty set, the output of the face elements in the candidate face set CFset is the recognition result.

6. The feature validity maintenance method according to claim 4, characterized in that, When a topological element is an edge element, methods for identifying unique recognition results based on the reference name of the topological elements in the new geometric model include: Step B2-1. Resolve the reference name of the current topology element. The original name in Obtain the original name and original name of each topological element in the new geometric model. Edge elements that satisfy the subset relation are used to construct a candidate face set. If the candidate face set If the set is empty, the output recognition result is that the referenced face of the current topological element has been deleted; if the candidate face set is empty... If the set is non-empty, proceed to step B2-2; Step B2-2. Continue resolving reference names The set of original names of adjacent faces in the dataset AdjFaceONSet(e) is used to remove candidate faces. In and reference name The set of original names of adjacent faces, AdjFaceONSet(e), contains edge elements that do not satisfy the subset relation; if the candidate face set... If the set is empty, the output recognition result is "referenced face does not exist," and the recognition ends; determine the candidate face set. Does the edge element within the candidate face set have an associated orientation information set SymActFeatALoc(e)? The edge elements within the set do not have an associated orientation information set SymActFeatALoc(e), so output the candidate face set. The output of the edge elements is the recognition result; when the edge elements in the candidate face set CFset have an attached orientation information set SymActFeatALSet(e), jump to step B2-3; Step B2-3. Continue resolving reference names. The associated orientation information set SymActFeatALoc(e) is used to eliminate candidate face sets. In and reference name The associated orientation information set SymActFeatALoc(e) does not satisfy the subset relation for edge elements; if the candidate face set If the result is empty, the output will indicate that the referenced face does not exist, and the identification process will end; if the candidate face set is empty... Given a non-empty set, determine the candidate face set. Does the edge element within the candidate face set contain edge segmentation information EdgeCutInfo(e)? If the edge elements within the line do not contain edge information (EdgeCutInfo(e)), output the candidate face set. The output of the edge elements within the candidate face set CFset is the recognition result; if the edge elements within the candidate face set CFset contain segmentation edge information EdgeCutInfo(e), proceed to step B2-4. Step B2-4. Continue resolving reference names. EdgeCutInfo(e) is used to remove candidate face sets. In and reference name EdgeCutInfo(e) is a segmentation edge information that does not satisfy the subset relation for edge elements; if the candidate face set If the result is empty, the output will indicate that the referenced face does not exist, and the identification process will end; if the candidate face set is empty... Given a non-empty set, the output of the face elements in the candidate face set CFset is the recognition result.

7. The feature validity maintenance method according to claim 4, characterized in that, When the topological element is a point element, methods for identifying the unique identification result of the topological element of the new geometric model based on the reference name include: Step B3-1. Resolve the reference name of the current topology element. The original name in Obtain the original name and original name of each topological element in the new geometric model. Points that satisfy the subset relation are used to construct a candidate face set. If the candidate face set If the set is empty, the output recognition result is that the referenced face of the current topological element has been deleted; if the candidate face set is empty... If the set is non-empty, proceed to step B3-2; Step B3-2. Continue resolving reference names The set of original names of adjacent faces in the dataset AdjFaceONSet(v) is used to remove candidate faces. In and reference name The set of original names of adjacent faces, AdjFaceONSet(v), contains points whose subset relations are not satisfied; if the candidate face set... If the set is empty, the output recognition result is "reference surface does not exist", and the recognition ends. Determine the candidate face set If the vertex elements in the candidate face set CFset contain a source edge information set InhEdgeInfoSet(v), proceed to step B3-3; otherwise, proceed to step B3-3. If the point element does not exist in the source edge information set InhEdgeInfoSet(v), proceed to step B3-4; Step B3-3. Continue resolving reference names. The original edge information set InhEdgeInfoSet(v) is used to remove candidate face sets. In and reference name The original edge information set InhEdgeInfoSet(v) contains point elements that do not satisfy the subset relation; if the candidate face set If the result is empty, the output will indicate that the referenced face does not exist, and the identification process will end; if the candidate face set is empty... Given a non-empty set, output the candidate face set. The output of the point elements within is the recognition result; Step B3-4. Continue resolving reference names. The reference name set AdjEdgeRNSet(v) in the middle, removes the candidate face set. In and reference name The reference name set AdjEdgeRNSet(v) contains point elements that do not satisfy the subset relation; if the candidate face set If the result is empty, the output will indicate that the referenced face does not exist, and the identification process will end; if the candidate face set is empty... Given a non-empty set, output the candidate face set. The output of the point elements is the recognition result.

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