CN117272855A

CN117272855A - Object surface geometric model generation method and device, electronic equipment and storage medium

Info

Publication number: CN117272855A
Application number: CN202311109067.4A
Authority: CN
Inventors: 丁力
Original assignee: China Automotive Innovation Co Ltd
Current assignee: China Automotive Innovation Co Ltd
Priority date: 2023-08-30
Filing date: 2023-08-30
Publication date: 2023-12-22

Abstract

The invention discloses a method, a device, electronic equipment and a storage medium for generating an object surface geometric model, wherein the method comprises the steps of determining an intersecting grid unit corresponding to each initial surface geometric unit according to vertex coordinate information of the initial surface geometric unit in an initial surface geometric model of a target object and coordinate information of grid points of grid units in a Cartesian grid, determining an external grid unit positioned outside the initial surface geometric model from non-intersecting grid units in the Cartesian grid based on preset grid units, cutting interfaces between the intersecting grid units and adjacent external grid units, and projecting the geometric units obtained by cutting to positions of the corresponding initial surface geometric units on the surface of the target object to generate the target surface geometric model. The method and the device can realize automatic generation of the geometric model of the object surface, improve the generation efficiency and the generation effect, and are also applicable to dirty geometry with small gaps and interference.

Description

Object surface geometric model generation method and device, electronic equipment and storage medium

Technical Field

The present invention relates to the field of computer aided engineering technology, and in particular, to a method and apparatus for generating a geometric model of an object surface, an electronic device, and a storage medium.

Background

In the process of computer aided engineering (Computer Aided Engineering, CAE) simulation analysis, geometric objects created by computer aided design (Computer Aided Design, CAD) software have defects such as gaps, holes, interference, and the like, more or less, the defects of the geometric objects need to be repaired, and a surface geometric model of the geometric objects is generated based on the repaired geometric objects, and the process accounts for more than 80% of the workload of the whole simulation process. However, the existing process is basically manual operation, so that the labor cost is greatly consumed, the efficiency is low, the generation effect of the surface geometric model is poor, and the application requirement of the subsequent hydrodynamic simulation analysis on the surrounding environment of the target object is difficult to meet.

Disclosure of Invention

Aiming at the problems in the prior art, the invention discloses a method, a device, electronic equipment and a storage medium for generating the geometric model of the object surface, which can realize the automatic generation of the geometric model of the object surface, improve the generation efficiency and the generation effect, are also applicable to dirty geometry with small gaps and interference, and further improve the accuracy of the subsequent hydrodynamic simulation analysis of the object. The technical scheme disclosed by the invention is as follows:

According to an aspect of the disclosed embodiments of the present invention, there is provided a method for generating a geometric model of an object surface, including:

acquiring an initial surface geometric model of a target object and a Cartesian grid corresponding to the initial surface geometric model;

determining intersecting grid cells corresponding to each initial surface geometry cell in the initial surface geometry model from the Cartesian grid according to the first position information and the second position information; the first position information is vertex coordinate information of each initial surface geometric unit, and the second position information is coordinate information of grid points of each grid unit in the Cartesian grid;

determining a target external grid cell positioned outside the initial surface geometric model from non-intersecting grid cells in the Cartesian grid based on a preset grid cell, wherein the preset grid cell is a grid cell of which the position information in the Cartesian grid meets a preset condition;

cutting the interface between the intersecting grid cell and a target adjacent grid cell to obtain a cutting geometric cell corresponding to the intersecting grid cell, wherein the target adjacent grid cell is a target external grid cell adjacent to the intersecting grid cell;

And projecting the segmentation geometric unit to a target surface position to obtain a target surface geometric model of the target object, wherein the target surface position is the position of the initial surface geometric unit corresponding to the intersection grid unit on the surface of the target object.

Optionally, the determining, according to the first position information and the second position information, the intersecting grid cell corresponding to each initial surface geometry cell in the initial surface geometry model from the cartesian grid includes:

determining third location information of each initial surface geometry unit in the Cartesian grid based on the first location information;

determining an associated grid cell corresponding to each initial surface geometric cell from the Cartesian grid based on the third position information and the first grid arrangement sequence number corresponding to each grid cell;

and determining the intersected grid cell corresponding to each initial surface geometric cell from the associated grid cells according to the first position information and the second position information.

Optionally, the determining, according to the first location information and the second location information, the intersecting grid cell corresponding to each initial surface geometry cell from the associated grid cells includes:

Determining midpoint position information of each initial surface geometric unit according to the first position information;

determining the position relation between grid points of the associated grid cells corresponding to each initial surface geometric cell and each initial surface geometric cell based on the midpoint position information and the second position information;

and determining the intersected grid cells corresponding to each initial surface geometric cell from the associated grid cells based on the position relation.

Optionally, the determining, based on the positional relationship, the intersecting grid cell corresponding to each initial surface geometry cell from the associated grid cells includes:

and determining the associated grid cell corresponding to each initial surface geometric cell as the intersected grid cell under the condition that the position relation characterizes that the grid point non-uniformity of the associated grid cell corresponding to each initial surface geometric cell is on the inner side of each initial surface geometric cell and the position relation characterizes that the grid point non-uniformity of the associated grid cell corresponding to each initial surface geometric cell is on the outer side of each initial surface geometric cell.

Optionally, the first position information includes upper limit coordinate information and lower limit coordinate information, and the determining, based on the first position information, third position information of each initial surface geometry unit in the cartesian grid includes:

Converting the upper limit coordinate information into a second grid arrangement sequence number of each initial surface geometric unit in the Cartesian grid based on a preset conversion relation, and converting the lower limit coordinate information into a third grid arrangement sequence number of each initial surface geometric unit in the Cartesian grid; the preset conversion relation characterizes the conversion relation between the vertex coordinate information of each initial surface geometric unit and the grid arrangement sequence number, the upper limit coordinate information is the vertex coordinate information which is larger than a first preset threshold value in each initial surface geometric unit, and the lower limit coordinate information is the vertex coordinate information which is smaller than a second preset threshold value in each initial surface geometric unit;

and taking the second grid arrangement sequence number and the third grid arrangement sequence number as third position information of each initial surface geometric unit in the Cartesian grid.

Optionally, the determining, based on the third location information and the first grid arrangement sequence number corresponding to each grid cell, the associated grid cell corresponding to each initial surface geometry cell from the cartesian grid includes:

determining a grid ordering range of each initial surface geometry unit in the Cartesian grid based on the second grid ordering number and the third grid ordering number;

And determining the associated grid unit corresponding to each initial surface geometric unit from the Cartesian grid based on the first grid arrangement sequence number and the grid arrangement range.

Optionally, the determining, based on the preset grid cell, a target external grid cell located outside the initial surface geometric model from non-intersecting grid cells in the cartesian grid includes:

taking the preset grid cell as a current grid cell;

taking non-intersecting grid cells in adjacent grid cells of the current grid cell as initial external grid cells;

and re-using the initial external grid unit as the current grid unit, repeating the step of using the non-intersecting grid unit in the adjacent grid units of the current grid unit as the initial external grid unit until the non-intersecting grid unit does not exist in the adjacent grid units of the current grid unit, and using the preset grid unit and the initial external grid unit determined each time as the target external grid unit.

According to another aspect of the disclosed embodiments of the present invention, there is provided an object surface geometric model generating apparatus including:

the acquisition module is used for acquiring an initial surface geometric model of the target object and a Cartesian grid corresponding to the initial surface geometric model;

An intersecting grid cell determining module, configured to determine, from the cartesian grid, intersecting grid cells corresponding to each initial surface geometry cell in the initial surface geometry model according to the first location information and the second location information; the first position information is vertex coordinate information of each initial surface geometric unit, and the second position information is coordinate information of grid points of each grid unit in the Cartesian grid;

a target external grid unit determining module, configured to determine, from non-intersecting grid units in the cartesian grid, a target external grid unit located outside the initial surface geometric model based on a preset grid unit, where the preset grid unit is a grid unit in which position information in the cartesian grid meets a preset condition;

the segmentation module is used for segmenting the interface between the intersecting grid cell and the target adjacent grid cell to obtain a segmentation geometric cell corresponding to the intersecting grid cell, wherein the target adjacent grid cell is a target external grid cell adjacent to the intersecting grid cell;

the target surface geometric model generation module is used for projecting the segmentation geometric unit to a target surface position to obtain a target surface geometric model of the target object, wherein the target surface position is the position of an initial surface geometric unit corresponding to the intersection grid unit on the surface of the target object.

According to another aspect of the disclosed embodiments of the present invention, there is provided an electronic apparatus including: a processor; a memory for storing the processor-executable instructions; wherein the processor is configured to execute the instructions to implement the object surface geometric model generation method of any one of the above.

According to another aspect of the disclosed embodiments of the invention, there is provided a computer readable storage medium, which when executed by a processor of an electronic device, causes the electronic device to perform the object surface geometric model generation method of any one of the above-described embodiments of the disclosure.

According to another aspect of the disclosed embodiments of the invention, there is provided a computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of generating a geometric model of an object surface according to any of the above-described embodiments of the invention.

The data processing method provided by the invention has the following technical effects:

according to the object surface geometric model generation method provided by the invention, the initial surface geometric model of the target object and the Cartesian grids corresponding to the initial surface geometric model are obtained, the intersection grid unit corresponding to each initial surface geometric unit is determined from the Cartesian grids according to the vertex coordinate information of the initial surface geometric unit in the initial surface geometric model of the target object and the coordinate information of grid points of grid units in the Cartesian grids, the outer boundary of the initial surface geometric model can be determined according to the grid units intersected with the surface geometric unit, the good fault tolerance is achieved, the same application to dirty geometric shapes with small gaps and interference is achieved, the external grid units located outside the initial surface geometric model are determined from non-intersecting grid units in the Cartesian grids based on the preset grid units, the interfaces between the intersection grid units and the adjacent external grid units are cut, and the cut obtained geometric units are projected to the positions of the corresponding initial surface geometric units on the surface of the target object, so that the object surface geometric model is generated, and the automatic generation efficiency and the accuracy of the subsequent object fluid simulation analysis are improved.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram illustrating an application environment for an object surface geometric model generation method, according to an example embodiment;

FIG. 2 is a flow diagram illustrating a method of generating a geometric model of an object surface according to an exemplary embodiment;

FIG. 3 is a flow diagram illustrating a method of determining intersecting grid cells corresponding to an initial surface geometry cell, according to an exemplary embodiment;

FIG. 4 is a flow diagram illustrating another method of determining intersecting grid cells corresponding to an initial surface geometry cell, according to an example embodiment;

FIG. 5 is a flow diagram illustrating a method of determining a target external grid cell that is external to an initial surface geometry model, according to an exemplary embodiment;

FIG. 6 is a block diagram of an object surface geometric model generation apparatus, according to an example embodiment;

FIG. 7 is a block diagram of a terminal electronic device for generating a geometric model of an object surface, according to an example embodiment;

FIG. 8 is a block diagram of a server electronic device for generating a geometric model of an object surface, according to an example embodiment.

Detailed Description

In order that those skilled in the art will better understand the disclosed embodiments of the present invention, a detailed description of the disclosed embodiments of the present invention will be provided with reference to the accompanying drawings. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present disclosure and in the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the disclosed embodiments of the invention described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or server that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed or inherent to such process, method, article, or apparatus, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

In the CAE simulation process, the geometry created by CAD software may have defects such as gaps, holes, interference, etc. more or less, and the engineer first needs to repair all the geometric defects, and then generates a surface mesh suitable for CAE based on the repaired geometry, which is called wrapping. Geometric wrapping is a very important and tedious work, accounts for more than 80% of the workload of the whole simulation process, is basically manual operation, and is time-consuming and labor-consuming, and extremely tests the professional level and the endurance of engineers. Therefore, the invention provides an automatic flour wrapping method, which can realize automatic flour wrapping for various geometries without manual intervention, shortens the flour wrapping working period from month to minute, greatly improves the working efficiency, saves manpower and material resources, has good fault tolerance, is applicable to dirty geometries with small gaps and interference, and has the characteristics of high processing speed, high automation degree, strong universality and the like.

Referring to fig. 1, fig. 1 is a schematic view illustrating an application environment of an object surface geometric model generating method according to an exemplary embodiment, where the application environment may include a server 01 and a terminal 02.

In an alternative embodiment, the server 01 may be used for performing the calculation process based on an object surface geometry model generation method. Specifically, the server 01 may be an independent physical server, or may be a server cluster or a distributed system formed by a plurality of physical servers, or may be a cloud server that provides cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, a content delivery network (Content Delivery Network, CDN), and basic cloud computing services such as big data and an artificial intelligence platform.

In an alternative embodiment, the terminal 02 may perform the calculation process in combination with the object surface geometric model generation method of the server 01. Specifically, the terminal 02 may include, but is not limited to, a smart phone, a desktop computer, a tablet computer, a notebook computer, a smart speaker, a digital assistant, an augmented reality (augmented reality, AR)/Virtual Reality (VR) device, a smart wearable device, and other types of electronic devices. Alternatively, the operating system running on the electronic device may include, but is not limited to, an android system, an IOS system, a Linux system, a Windows system, a Unix system, and the like.

For example, the terminal 02 acquires an initial surface geometric model of the target object and a cartesian grid corresponding to the initial surface geometric model, and transmits the initial surface geometric model and the cartesian grid to the server 01; determining, by the server 01, intersecting grid cells corresponding to each of the initial surface geometry cells in the initial surface geometry model from the cartesian grid according to the first location information and the second location information; determining a target external grid cell located outside the initial surface geometric model from among non-intersecting grid cells in the cartesian grid based on the preset grid cell; cutting the interface between the intersecting grid cell and the target adjacent grid cell to obtain a cutting geometric cell corresponding to the intersecting grid cell; and projecting the segmentation geometric unit to the target surface position to obtain a target surface geometric model of the target object, and transmitting the target surface geometric model to the terminal 02.

In addition, it should be noted that, fig. 1 shows only an application environment of the object surface geometric model generating method, and the embodiment of the present disclosure is not limited to the above.

In the embodiment of the present disclosure, the server 01 and the terminal 02 may be directly or indirectly connected through a wired or wireless communication method, which is not limited herein.

FIG. 2 is a flow chart illustrating a method of generating a geometric model of an object surface, according to an exemplary embodiment, the present disclosure provides the method operational steps as described in the examples or flow charts, but may include more or fewer operational steps based on conventional or non-inventive labor. The order of steps recited in the embodiments is merely one way of performing the order of steps and does not represent a unique order of execution. When implemented in a real system or server product, the methods illustrated in the embodiments or figures may be performed sequentially or in parallel (e.g., in a parallel processor or multithreaded environment). Specifically, as shown in fig. 2, the method may include:

s201: and acquiring an initial surface geometric model of the target object and a Cartesian grid corresponding to the initial surface geometric model.

In a specific embodiment, the target object may be an object that needs to generate a precise surface geometry model, such as an automobile, an aircraft, etc., the initial surface geometry model of the target object may be a stereolithography geometry model that roughly describes the surface profile of the target object, the initial surface geometry model may include a plurality of initial surface geometry units, specifically, each initial surface geometry unit may be triangular in shape, each initial surface geometry unit may correspond to one unit identification information, specifically, the unit identification information may be a unit number, and the corresponding initial surface geometry unit may be determined according to the unit identification information.

In a specific embodiment, the initial surface geometry model of the target object may be obtained by reading an initial stereolithography geometry file (STL file), and in particular, the initial stereolithography geometry file may include vertex coordinate information of each initial surface geometry unit in the initial surface geometry model, unit identification information of each initial surface geometry unit, and a unit normal vector of each initial surface geometry unit.

In a specific embodiment, the cartesian grid may be a hexahedron, the cartesian grid may include a plurality of grid cells, each grid cell may be a hexahedron, each grid cell may be written as a unit, and in particular, the cartesian grid and each grid cell therein may be a cuboid or a cube; each grid cell corresponds to a first grid arrangement sequence number, the first grid arrangement sequence number can represent the position sequence of the corresponding grid cell in the Cartesian grid, specifically, the calculation domain origin corresponding to the initial surface geometric model, namely, the origin of the Cartesian grid is taken as the initial position and is marked as (0, 0), the first grid arrangement sequence number of the grid cell taking the point as the vertex is marked as (1, 1), the 1 st grid cell along the x-axis direction, the 1 st grid cell along the y-axis direction and the 1 st grid cell along the z-axis direction are represented, and if the first grid arrangement sequence number of a certain grid cell is (8,3,5), the grid cell is the 8 th grid cell along the x-axis direction, the 3 rd grid cell along the y-axis direction and the 5 th grid cell along the z-axis direction are represented; the first grid arrangement sequence number is independent of the step length of the grid unit and is only related to the origin position of the Cartesian grid.

In practical application, the cartesian grid can be divided based on the preset grid resolution to obtain a plurality of grid units, and specifically, the cartesian grid can be equally divided based on the preset grid resolution to be dispersed into a plurality of uniform grid units; the preset grid resolution can be set according to actual application requirements, specifically, the preset grid resolution can be set to be 1% of the maximum coordinate value of the initial surface geometric model in the coordinate axis direction, and the smaller the preset grid resolution is, the more grid units are, so that the higher the accuracy of the finally generated surface geometric model can be.

In a specific embodiment, a cartesian grid capable of completely surrounding the initial surface geometric model may be generated according to the region information corresponding to the initial surface geometric model, where the area occupied by the cartesian grid is slightly larger than the area occupied by the initial surface geometric model, and specifically, the region information corresponding to the initial surface geometric model may be determined according to the length, width and height information corresponding to the initial surface geometric model, or may be determined according to the minimum vertex coordinate information and the maximum vertex coordinate information of a plurality of initial surface geometric units. For example, in the process of generating a cartesian grid according to the length, width and height information corresponding to the initial surface geometric model, the longest position of a certain initial surface geometric model in the length direction is 19.5 units, the widest position in the width direction is 11.8 units, and the widest position in the height direction is 7.6 units, so that the generated cartesian grid has at least 20 grid cells in the length direction, at least 12 grid cells in the width direction, and at least 8 grid cells in the height direction.

S203: and determining an intersecting grid cell corresponding to each initial surface geometric cell in the initial surface geometric model from the Cartesian grid according to the first position information and the second position information.

In a specific embodiment, the first position information may be vertex coordinate information of each initial surface geometry cell, and the second position information may be coordinate information of grid points of each grid cell in a cartesian grid.

In an alternative embodiment, fig. 3 is a schematic flow chart of a method for determining intersecting grid cells corresponding to initial surface geometric cells according to an exemplary embodiment, and as shown in fig. 3, determining, from a cartesian grid, intersecting grid cells corresponding to each initial surface geometric cell in the initial surface geometric model according to the first location information and the second location information may include:

s301: third location information of each initial surface geometry unit in the Cartesian grid is determined based on the first location information.

In a specific embodiment, the first position information may include upper limit coordinate information and lower limit coordinate information, where the upper limit coordinate information may be vertex coordinate information greater than a first preset threshold in each initial surface geometry unit, the lower limit coordinate information may be vertex coordinate information smaller than a second preset threshold in each initial surface geometry unit, specifically, the upper limit coordinate information may be maximum vertex coordinate information in each initial surface geometry unit, the lower limit coordinate information may be minimum vertex coordinate information in each initial surface geometry unit, and the first preset threshold and the second preset threshold may be set according to actual application requirements; the third location information may characterize a range of grid cells covered by each initial surface geometry cell in a cartesian grid.

In an alternative embodiment, determining the third location information of each initial surface geometry unit in the cartesian grid based on the first location information may include:

based on a preset conversion relation, converting the upper limit coordinate information into a second grid arrangement sequence number of each initial surface geometric unit in the Cartesian grid, and converting the lower limit coordinate information into a third grid arrangement sequence number of each initial surface geometric unit in the Cartesian grid;

In a specific embodiment, the preset conversion relationship may represent a conversion relationship between vertex coordinate information and mesh arrangement sequence number of each initial surface geometric unit, and specifically, the preset conversion relationship may be expressed by the following formula:

taking the example of converting the upper limit coordinate information into a second grid arrangement sequence number of each initial surface geometric unit in a Cartesian grid, i represents a grid arrangement sequence number in a horizontal axis direction in the second grid arrangement sequence number, j represents a grid arrangement sequence number in a vertical axis direction in the second grid arrangement sequence number, k represents a grid arrangement sequence number in a vertical axis direction in the second grid arrangement sequence number, x represents an abscissa in the upper limit coordinate information, y represents an ordinate in the upper limit coordinate information, z represents an ordinate in the upper limit coordinate information, x _{minbackground} Representing the minimum abscissa, y, of a Cartesian grid _{minbackground} Representing the minimum ordinate, z, of a Cartesian grid _{minbackground} Representing the minimum vertical coordinates of the Cartesian grid, int represents the downward rounding, and Δ represents the unit grid spacing of the Cartesian grid.

S303: and determining the associated grid cell corresponding to each initial surface geometric cell from the Cartesian grid based on the third position information and the first grid arrangement sequence number corresponding to each grid cell.

In an optional embodiment, determining, from the cartesian grid, the associated grid cell corresponding to each initial surface geometry cell based on the third location information and the first grid arrangement sequence number corresponding to each grid cell may include:

determining a grid ordering range of each initial surface geometric unit in the Cartesian grid based on the second grid arrangement sequence number and the third grid arrangement sequence number;

In a specific embodiment, the associated grid cell corresponding to each initial surface geometry cell may be determined according to whether the grid arrangement sequence number of the grid cell falls within the grid arrangement range, specifically, may be determined by comparing the size relationships between the first grid arrangement sequence number and the second grid arrangement sequence number, and the third grid arrangement sequence number, and if the first grid arrangement sequence number is between the second grid arrangement sequence number and the third grid arrangement sequence number, it indicates that the grid arrangement sequence number of the grid cell falls within the grid arrangement range of the initial surface geometry cell, that is, the grid cell is the associated grid cell of the initial surface geometry cell.

In a specific embodiment, the associated mesh unit of the vertex corresponding to the minimum coordinate information of each initial surface geometry unit may be determined according to the fact that the second mesh arrangement sequence number falls into the range between the first mesh arrangement sequence numbers corresponding to two adjacent mesh units, and the determination of the third mesh arrangement sequence number is the same, so that the associated mesh unit of the vertex corresponding to the maximum coordinate information of each initial surface geometry unit may be determined, and the associated mesh unit corresponding to the two vertices and the mesh unit between the two vertices are determined as the associated mesh unit corresponding to each initial surface geometry unit, that is, the mesh unit covered by each initial surface geometry unit.

In the embodiment, the grid arrangement sequence number is introduced, and the associated grid units corresponding to the surface geometric units are determined from the Cartesian grid according to the grid arrangement sequence number, so that the positions of the surface geometric units and the grid units can be rapidly positioned in the space retrieval process, and the efficiency is improved.

S305: and determining an intersecting grid cell corresponding to each initial surface geometric cell from the associated grid cells according to the first position information and the second position information.

In an alternative embodiment, fig. 4 is a flowchart of another method for determining intersecting grid cells corresponding to initial surface geometry cells according to an exemplary embodiment, and as shown in fig. 4, determining, from the associated grid cells, the intersecting grid cells corresponding to each initial surface geometry cell according to the first location information and the second location information may include:

S401: midpoint position information of each of the initial surface geometry units is determined based on the first position information.

In a specific embodiment, the midpoint position information may be generated according to an average value of the vertex coordinate information of each initial surface geometric unit, and specifically, the average value of the vertex coordinate information of each initial surface geometric unit may be directly used as the midpoint position information.

S403: and determining the position relation between the grid points of the associated grid cells corresponding to each initial surface geometric cell and each initial surface geometric cell based on the midpoint position information and the second position information.

In a specific embodiment, the above positional relationship may include grid points inside the initial surface geometry unit and grid points outside the initial surface geometry unit.

In a specific embodiment, determining, based on the midpoint location information and the second location information, a positional relationship between the grid points of the associated grid cells corresponding to each initial surface geometric cell and each initial surface geometric cell may include: constructing a target vector corresponding to each initial surface geometric unit based on the midpoint position information and the second position information; calculating the dot product of the target vector corresponding to each initial surface geometric unit and the unit normal vector; and determining that the grid points are inside the initial surface geometric unit when the calculation result of the dot product is negative, and determining that the grid points are outside the initial surface geometric unit when the calculation result of the dot product is positive.

Specifically, the target vector may be constructed with the point corresponding to the midpoint position information as a start point and any grid point of the associated grid unit as an end point. The above-described process of determining the positional relationship is performed for each grid point of each associated grid cell corresponding to each initial surface geometric cell.

S405: based on the positional relationship, an intersecting grid cell corresponding to each initial surface geometry cell is determined from the associated grid cells.

In an alternative embodiment, determining, based on the location relationship, the intersecting grid cell corresponding to each initial surface geometry cell from the associated grid cells may include:

and determining the associated grid cell corresponding to each initial surface geometry cell as an intersecting grid cell in the case that the position relationship characterizes that the grid point non-uniformity of the associated grid cell corresponding to each initial surface geometry cell is inside each initial surface geometry cell and the position relationship characterizes that the grid point non-uniformity of the associated grid cell corresponding to each initial surface geometry cell is outside each initial surface geometry cell.

Specifically, after determining the associated grid cell corresponding to each initial surface geometry cell as an intersecting grid cell, cell identification information of the initial surface geometry cell corresponding to the intersecting grid cell may be recorded, so that the corresponding initial surface geometry cell can be determined according to the intersecting grid cell.

In a specific embodiment, when the position relationship indicates that the grid points of the associated grid cells corresponding to each initial surface geometry cell are all on the inner side of each initial surface geometry cell, or the position relationship indicates that the grid points of the associated grid cells corresponding to each initial surface geometry cell are all on the outer side of each initial surface geometry cell, it may be determined that the associated grid cells corresponding to each initial surface geometry cell do not intersect with the initial surface geometry cell, that is, are non-intersecting grid cells.

In the above embodiment, the positional relationship between the grid points of the associated grid cells and the corresponding surface geometry cells is determined according to the vertex coordinate information of the surface geometry cells and the coordinate information of the grid points of the associated grid cells, so that the grid cells intersecting the surface geometry cells can be quickly determined from the associated grid cells, and the outer boundary of the surface geometry model can be determined according to the grid cells intersecting the surface geometry cells, so that the method has good fault tolerance and is also applicable to dirty geometry with small gaps and interference.

S205: based on the preset grid cells, a target external grid cell located outside the initial surface geometry model is determined from the non-intersecting grid cells in the Cartesian grid.

In a specific embodiment, the preset grid cell may be a grid cell in which the position information in the cartesian grid satisfies a preset condition, and in particular, the preset grid cell may be a grid cell that is necessarily located outside the initial surface geometric model, for example, a grid cell with the smallest coordinates; since the area occupied by the cartesian grid is slightly larger than the area occupied by the initial surface geometry model, there must be at least one grid cell located outside the initial surface geometry model.

In an alternative embodiment, fig. 5 is a flowchart illustrating a method for determining a target external grid cell located outside the initial surface geometric model according to an exemplary embodiment, and determining, based on the preset grid cell, the target external grid cell located outside the initial surface geometric model from non-intersecting grid cells in the cartesian grid, as shown in fig. 5, may include:

s501: and taking the preset grid cell as the current grid cell.

S503: non-intersecting ones of the neighboring cells of the current cell are taken as initial outer cells.

S505: and re-using the initial external grid unit as the current grid unit, repeating the step of using the non-intersecting grid unit in the adjacent grid units of the current grid unit as the initial external grid unit until the non-intersecting grid unit does not exist in the adjacent grid units of the current grid unit, and using the preset grid unit and the initial external grid unit determined each time as the target external grid unit.

In a specific embodiment, taking the grid cell with the smallest coordinate as a starting grid cell, firstly searching for a non-intersecting grid cell in adjacent grid cells of the grid cell with the smallest coordinate, and taking the non-intersecting grid cell as a grid cell positioned outside the initial surface geometric model; next, searching non-intersecting grid cells in adjacent grid cells of the external grid cells determined in the previous step, and taking the non-intersecting grid cells as grid cells positioned outside the initial surface geometric model; and (3) circulating the process until no non-intersecting grid cells exist in the searched adjacent grid cells, ending the circulation, and taking the initial grid cell and the external grid cells searched each time as target external grid cells.

S207: and cutting the interface between the intersected grid unit and the adjacent grid unit of the target to obtain a cutting geometric unit corresponding to the intersected grid unit.

In a specific embodiment, the target adjacent grid cell may be a target external grid cell adjacent to the intersecting grid cell, and the segmentation geometry cell may be a triangle cell; the interface between the intersection grid cell and the adjacent target external grid cell may be split into at least two triangle cells, and in particular, in the case where the grid cell is rectangular or square, the interface between the intersection grid cell and the adjacent target external grid cell may be split into two triangle cells along the diagonal.

S209: and projecting the segmentation geometric unit to the target surface position to obtain a target surface geometric model of the target object.

In a specific embodiment, the target surface position may be a position of an initial surface geometric unit corresponding to the intersecting grid unit in the initial surface geometric model, that is, a position on the surface of the target object, and specifically, the initial surface geometric unit corresponding to the intersecting grid unit may be determined according to the unit identification information recorded in the process of determining the intersecting grid unit, so as to project the segmentation geometric unit corresponding to the intersecting grid unit to the position of the corresponding initial surface geometric unit; the target surface geometry model may be a stereolithography geometry model that accurately describes the surface topography of the target object.

In a specific embodiment, after the target surface geometric model is obtained, a target stereolithography geometric file (STL file) may be generated according to the target surface geometric model, where the target stereolithography geometric file may include vertex coordinate information of each target surface geometric unit (i.e., a sliced geometric unit after projection) in the target surface geometric model, unit identification information of each target surface geometric unit, and a unit normal vector of each target surface geometric unit, specifically, the unit normal vector of each target surface geometric unit may be calculated based on the vertex coordinate information of the sliced geometric unit after projection, and the unit identification information of each target surface geometric unit may be determined according to an order of each target surface geometric unit in the target stereolithography geometric file, and a direction of the unit normal vector of each target surface geometric unit may be determined according to an order of the vertex coordinate information of each target surface geometric unit in the target stereolithography geometric file, so that in writing the above information into the preset file to generate the target stereolithography file, a write order of the vertex coordinate information of each target surface geometric unit needs to be defined so that the unit normal vector of each target surface geometric unit points to the outside of the target object.

In a specific implementation manner, the specific implementation process of the technical solution in the embodiment of the present application is as follows:

(1) The initial STL file is read to acquire an initial surface geometric model of the target object, and the initial STL file comprises vertex coordinate information of each initial surface geometric unit in the initial surface geometric model, a unit number of each initial surface geometric unit and a unit normal vector of each initial surface geometric unit.

(2) Generating a Cartesian grid capable of completely surrounding the initial surface geometric model according to the region information corresponding to the initial surface geometric model, and equally dividing the Cartesian grid based on a preset grid resolution, so as to disperse the Cartesian grid into a plurality of uniform grid units, wherein each grid unit is a cube, each grid unit corresponds to a grid arrangement sequence number, and the preset grid resolution can be set to be 1% of the maximum coordinate value of the initial surface geometric model in the coordinate axis direction.

(3) An associated grid cell for each initial surface geometry cell is determined.

(1) Converting the minimum vertex coordinate information and the maximum vertex coordinate information of each initial surface geometric unit into corresponding grid arrangement sequence numbers according to the following formulas, thereby obtaining a grid ordering range of each initial surface geometric unit in a Cartesian grid;

The specific meaning of each symbol may be referred to in the foregoing, and will not be described herein.

(2) Comparing the grid arrangement sequence number of the grid unit with the grid arrangement sequence number corresponding to the minimum vertex coordinate information and the maximum vertex coordinate information of each initial surface geometric unit, and if the grid arrangement sequence number of the grid unit is between the grid arrangement sequence numbers corresponding to the minimum vertex coordinate information and the maximum vertex coordinate information of each initial surface geometric unit, determining that the grid unit is the associated grid unit of the initial surface geometric unit, wherein the grid arrangement sequence number of the grid unit falls in the grid arrangement range of the initial surface geometric unit in the Cartesian grid.

(4) A grid cell is determined from the associated grid cells that intersects each of the initial surface geometry cells.

(1) And taking a point corresponding to the average value of the vertex coordinate information of each initial surface geometric unit as a midpoint of each initial surface geometric unit, taking the midpoint of each initial surface geometric unit as a starting point, and taking each grid point of the associated grid unit corresponding to each initial surface geometric unit as an ending point to construct a vector corresponding to each initial surface geometric unit.

(2) And calculating the dot product of the unit normal vector of each initial surface geometric unit and the vector, if the dot product calculation result is negative, the corresponding grid point of the associated grid unit is positioned at the inner side of the corresponding initial surface geometric unit, and if the dot product calculation result is positive, the corresponding grid point of the associated grid unit is positioned at the outer side of the corresponding initial surface geometric unit.

(3) In the case where grid point non-uniformities of associated grid cells corresponding to each initial surface geometry cell are inside each initial surface geometry cell and grid point non-uniformities of associated grid cells corresponding to each initial surface geometry cell are outside each initial surface geometry cell, determining the associated grid cell as a grid cell intersecting the corresponding initial surface geometry cell, and recording a cell number of the corresponding initial surface geometry cell.

(5) From the grid cells that do not intersect the initial surface geometry cells, grid cells that lie outside the initial surface geometry model are determined.

(1) Since the area occupied by the cartesian grid is slightly larger than the area occupied by the initial surface geometric model, there must be at least one grid cell located outside the initial surface geometric model, and the grid cell with the smallest coordinates can be selected;

Searching non-intersecting grid cells (i.e., grid cells which do not intersect with the initial surface geometric model) in adjacent grid cells of the grid cells with the minimum coordinates serving as initial grid cells, and determining the non-intersecting grid cells as grid cells positioned outside the initial surface geometric model;

(2) searching for a non-intersecting grid cell in adjacent grid cells of the external grid cells determined in the previous step (i.e., the grid cells located outside the initial surface geometric model), and determining the non-intersecting grid cell as the grid cell located outside the initial surface geometric model;

(3) and (3) circulating the process until no non-intersecting grid cells exist in the searched adjacent grid cells, ending the circulation, and taking the grid cell with the minimum coordinates and the grid cell which is searched each time and is positioned outside the initial surface geometric model as the grid cell which is finally needed and is positioned outside the initial surface geometric model.

(6) A target surface geometry model of the target object is generated.

(1) Any one grid cell is selected from the grid cells intersected with each initial surface geometric cell, and whether any grid cell located outside the initial surface geometric model exists in the adjacent grid cells of the grid cell is searched.

(2) If so, extracting the interface of the two grid cells, dividing the interface into two triangle cells along the diagonal angle, and projecting each triangle cell to the position of the initial surface geometric cell corresponding to the intersected grid cell where the triangle cell is positioned on the surface of the target object, wherein the position of the initial surface geometric cell in the initial surface geometric model, namely the position on the surface of the target object, of the initial surface geometric cell can be determined by searching the initial surface geometric cell corresponding to the intersected grid cell according to the cell number recorded in the process of determining the intersected grid cell, so that the triangle cell divided by the interface is projected to the position of the initial surface geometric cell.

(3) If not, selecting the next grid unit.

(4) Repeating the steps until no next grid cell exists in the grid cells intersected with each initial surface geometric cell, and taking the model obtained by projection as a target surface geometric model.

(7) Taking the vertex coordinate information of the projected triangle units as the vertex coordinate information of each target surface geometric unit in the target surface geometric model, calculating to obtain a unit normal vector of each target surface geometric unit according to the vertex coordinate information of each target surface geometric unit, and writing the information into a preset file to generate a target STL file; defining a writing sequence of each target surface geometric unit in the writing process to determine a unit number of each target surface geometric unit, and defining a writing sequence of vertex coordinate information of each target surface geometric unit to enable a unit normal vector of each target surface geometric unit to point to the outside of a target object; the generated target STL file may include at least vertex coordinate information of each target surface geometric unit, a unit number of each target surface geometric unit, and a unit normal vector of each target surface geometric unit.

According to the technical scheme provided by the embodiment of the specification, the initial surface geometric model of the target object and the Cartesian grids corresponding to the initial surface geometric model are obtained, the intersecting grid units corresponding to each initial surface geometric unit are determined from the Cartesian grids according to the vertex coordinate information of the initial surface geometric unit in the initial surface geometric model of the target object and the coordinate information of grid points of grid units in the Cartesian grids, the outer boundary of the initial surface geometric model can be determined according to the grid units intersecting with the surface geometric units, the fault tolerance is good, the method is applicable to dirty geometric shapes with small gaps and interference, further, external grid units located outside the initial surface geometric model are determined from non-intersecting grid units in the Cartesian grids based on preset grid units, the intersecting grid units and interfaces between adjacent external grid units are cut, the cut-obtained geometric units are projected to positions of the corresponding initial surface geometric units on the surface of the target object, and the target surface geometric model is generated. In addition, the process does not relate to the three-dimensional curved surface grid generation process, so that the generation speed of the object surface geometric model can be improved, the generation period of the object surface geometric model is shortened from month to minute, the working efficiency is greatly improved, and meanwhile, the expenditure of manpower and material resources is saved.

The embodiment of the invention also provides a device for generating the geometric model of the object surface, as shown in fig. 6, which comprises:

an obtaining module 610, configured to obtain an initial surface geometric model of a target object and a cartesian grid corresponding to the initial surface geometric model;

an intersecting grid cell determination module 620, configured to determine, from the cartesian grid, intersecting grid cells corresponding to each of the initial surface geometry cells in the initial surface geometry model according to the first location information and the second location information; the first position information is vertex coordinate information of each initial surface geometric unit, and the second position information is coordinate information of grid points of each grid unit in the Cartesian grid;

a target external grid cell determining module 630, configured to determine, from among non-intersecting grid cells in the cartesian grid, a target external grid cell located outside the initial surface geometric model based on a preset grid cell, where the preset grid cell is a grid cell in which position information in the cartesian grid satisfies a preset condition;

the segmentation module 640 is configured to segment an interface between the intersecting grid cell and a target adjacent grid cell, so as to obtain a segmentation geometric cell corresponding to the intersecting grid cell, where the target adjacent grid cell is a target external grid cell adjacent to the intersecting grid cell;

And the target surface geometric model generating module 650 is configured to project the segmentation geometric unit to a target surface position, so as to obtain a target surface geometric model of the target object, where the target surface position is a position of an initial surface geometric unit corresponding to the intersecting grid unit on the surface of the target object.

Optionally, the intersecting grid cell determining module 620 includes:

a third position information determining unit configured to determine third position information of each of the initial surface geometry units in the cartesian grid based on the first position information;

a first associated grid cell determining unit, configured to determine an associated grid cell corresponding to each initial surface geometry cell from the cartesian grid based on the third location information and the first grid arrangement sequence number corresponding to each grid cell;

and the first intersecting grid cell determining unit is used for determining the intersecting grid cell corresponding to each initial surface geometric cell from the associated grid cells according to the first position information and the second position information.

Optionally, the first intersecting grid cell determining unit includes:

A midpoint position information determining unit configured to determine midpoint position information of each of the initial surface geometry units according to the first position information;

a position relation determining unit, configured to determine a position relation between grid points of the associated grid unit corresponding to each initial surface geometric unit and each initial surface geometric unit based on the midpoint position information and the second position information;

and the second intersecting grid cell determining unit is used for determining the intersecting grid cell corresponding to each initial surface geometric cell from the associated grid cells based on the position relation.

Optionally, the second intersecting grid cell determining unit includes:

and a third intersecting grid unit determining unit, configured to determine, as the intersecting grid unit, an associated grid unit corresponding to each initial surface geometry unit when the positional relationship indicates that grid point non-uniformity of the associated grid unit corresponding to each initial surface geometry unit is inside each initial surface geometry unit and the positional relationship indicates that grid point non-uniformity of the associated grid unit corresponding to each initial surface geometry unit is outside each initial surface geometry unit.

Optionally, the first location information includes upper limit coordinate information and lower limit coordinate information, and the third location information determining unit includes:

a fourth position information determining unit, configured to convert, based on a preset conversion relationship, the upper limit coordinate information into a second grid arrangement sequence number of each initial surface geometry unit in the cartesian grid, and convert the lower limit coordinate information into a third grid arrangement sequence number of each initial surface geometry unit in the cartesian grid; the preset conversion relation characterizes the conversion relation between the vertex coordinate information of each initial surface geometric unit and the grid arrangement sequence number, the upper limit coordinate information is the vertex coordinate information which is larger than a first preset threshold value in each initial surface geometric unit, and the lower limit coordinate information is the vertex coordinate information which is smaller than a second preset threshold value in each initial surface geometric unit;

and a fifth position information determining unit, configured to use the second grid arrangement sequence number and the third grid arrangement sequence number as third position information of each initial surface geometry unit in the cartesian grid.

Optionally, the first association grid cell determining unit includes:

A position range determining unit, configured to determine a grid ordering range of each initial surface geometry unit in the cartesian grid based on the second grid arrangement sequence number and the third grid arrangement sequence number;

and the second associated grid cell determining unit is used for determining the associated grid cell corresponding to each initial surface geometric cell from the Cartesian grid based on the first grid arrangement sequence number and the grid arrangement range.

Optionally, the target external grid cell determining module 630 includes:

a current unit determining unit, configured to take the preset grid unit as a current grid unit;

an initial external grid cell determination unit configured to take a non-intersecting grid cell of adjacent grid cells of the current grid cell as an initial external grid cell;

and the target external grid unit determining unit is used for re-using the initial external grid unit as the current grid unit, repeating the step of using the non-intersecting grid unit in the adjacent grid units of the current grid unit as the initial external grid unit until the non-intersecting grid unit does not exist in the adjacent grid units of the current grid unit, and using the preset grid unit and the initial external grid unit determined each time as the target external grid unit.

The specific manner in which the various modules perform the operations in the apparatus of the above embodiments have been described in detail in connection with the embodiments of the method, and will not be described in detail herein.

Fig. 7 is a block diagram of an electronic device, which may be a terminal, for generating a geometric model of an object surface, the internal structure of which may be as shown in fig. 7, according to an exemplary embodiment. The electronic device includes a processor, a memory, a network interface, a display screen, and an input device connected by a system bus. Wherein the processor of the electronic device is configured to provide computing and control capabilities. The memory of the electronic device includes a nonvolatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface of the electronic device is used for communicating with an external terminal through a network connection. The computer program is executed by a processor to implement a method of generating a geometric model of an object surface. The display screen of the electronic equipment can be a liquid crystal display screen or an electronic ink display screen, and the input device of the electronic equipment can be a touch layer covered on the display screen, can also be keys, a track ball or a touch pad arranged on the shell of the electronic equipment, and can also be an external keyboard, a touch pad or a mouse and the like.

Fig. 8 is a block diagram of an electronic device, which may be a server, for generating a geometric model of an object surface, the internal structure of which may be as shown in fig. 8, according to an example embodiment. The electronic device includes a processor, a memory, and a network interface connected by a system bus. Wherein the processor of the electronic device is configured to provide computing and control capabilities. The memory of the electronic device includes a nonvolatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface of the electronic device is used for communicating with an external terminal through a network connection. The computer program is executed by a processor to implement a method of generating a geometric model of an object surface.

It will be appreciated by those skilled in the art that the structures shown in fig. 7 or 8 are merely block diagrams of portions of structures related to the present disclosure and do not constitute a limitation of the electronic device to which the present disclosure is applied, and that a particular electronic device may include more or less components than those shown in the drawings, or may combine some components, or have a different arrangement of components.

In an exemplary embodiment, there is also provided an electronic device including: a processor; a memory for storing the processor-executable instructions; wherein the processor is configured to execute the instructions to implement an object surface geometric model generation method as in the disclosed embodiments of the invention.

In an exemplary embodiment, a computer readable storage medium is also provided, which when executed by a processor of an electronic device, causes the electronic device to perform the object surface geometric model generation method in the disclosed embodiments of the invention.

In an exemplary embodiment, a computer program product containing instructions is also provided, which when run on a computer, cause the computer to perform the object surface geometric model generation method in the disclosed embodiments of the invention.

Those skilled in the art will appreciate that implementing all or part of the above described methods may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed, may comprise the steps of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in embodiments provided herein may include non-volatile and/or volatile memory. The nonvolatile memory can include Read Only Memory (ROM), programmable ROM (PROM), electrically Programmable ROM (EPROM), electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms, such as Static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate

SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous Link (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), among others.

Other embodiments of the disclosed invention will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed invention. This application is intended to cover any variations, uses, or adaptations of the disclosure following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

It is to be understood that the present disclosure is not limited to the precise arrangements and instrumentalities shown in the drawings, and that various modifications and changes may be effected without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A method for generating a geometric model of an object surface, comprising:

2. The method of claim 1, wherein determining, from the cartesian grid, intersecting grid cells corresponding to each of the initial surface geometry cells in the initial surface geometry model based on the first location information and the second location information comprises:

3. The method of claim 2, wherein determining the intersecting grid cell corresponding to each initial surface geometry cell from the associated grid cells based on the first location information and the second location information comprises:

4. A method according to claim 3, wherein said determining, based on said positional relationship, said intersecting grid cells corresponding to each initial surface geometry cell from said associated grid cells comprises:

5. The method of claim 2, wherein the first location information includes upper and lower limit coordinate information, and wherein determining third location information for each of the initial surface geometry cells in the cartesian grid based on the first location information comprises:

6. The method of claim 5, wherein determining the associated grid cell corresponding to each initial surface geometry cell from the cartesian grid based on the third location information and the first grid arrangement sequence number corresponding to each grid cell comprises:

7. The method of claim 1, wherein the determining, based on a preset grid cell, a target external grid cell located outside the initial surface geometry model from among non-intersecting grid cells in the cartesian grid comprises:

taking the preset grid cell as a current grid cell;

8. An object surface geometric model generation apparatus, characterized in that the apparatus comprises:

9. An electronic device, comprising:

a processor;

a memory for storing the processor-executable instructions;

wherein the processor is configured to execute the instructions to implement the object surface geometric model generation method of any of claims 1 to 7.

10. A computer readable storage medium, characterized in that instructions in the storage medium, when executed by a processor of an electronic device, enable the electronic device to perform the object surface geometric model generation method of any one of claims 1 to 7.