A method for generating a target and water surface integrated grid model
By constructing an integrated mesh model of the target and the water surface, the problem of unrealistic simulation of target thermal characteristics in marine scene simulation was solved, and more accurate thermal characteristic simulation and heat conduction calculation were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING INST OF ENVIRONMENTAL FEATURES
- Filing Date
- 2022-12-21
- Publication Date
- 2026-07-31
AI Technical Summary
Existing technologies fail to effectively consider the thermal conduction effect of seawater on the target's sides in marine scene simulations, resulting in unrealistic simulations of the target's thermal characteristics against a water surface background.
An integrated mesh model of the target and the water surface is constructed. By generating an integrated mesh model of the target and the water surface, the heat transfer model of the water surface and the target is comprehensively considered, thereby improving the realism of the thermal characteristic simulation.
This improves the realism of target thermal characteristic simulation against a water surface background, and provides a more accurate finite element mesh model for calculating the heat conduction between the side of the target and the water body.
Smart Images
Figure CN115935749B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of target thermal characteristic simulation and analysis technology under water surface background, and particularly to a method for generating an integrated mesh model of target and water surface. Background Technology
[0002] Studying the infrared characteristics of targets against a water surface background allows for a direct and qualitative analysis of the contrast between the target and the background, which is of great demand and application value for the development of detection equipment. Currently, in the simulation of marine scenarios, by establishing a water surface infrared radiation model and combining it with the infrared radiation distribution model of the target surface, it is only possible to achieve a simple synthesis of the infrared results of the water surface background and the target. However, the influence of seawater on the heat conduction of the target's side is not taken into account, and the realism of the simulation of the target's thermal characteristics against a water surface background cannot be guaranteed.
[0003] Therefore, there is an urgent need to construct a mesh model that integrates the target and background, comprehensively considers the heat transfer model of the water surface and the target, and improves the realism of the simulation of the target's thermal characteristics against the background of the water surface. Summary of the Invention
[0004] This invention provides a method for generating an integrated target-water surface mesh model, which ultimately generates an integrated target-water surface mesh model that can be applied to consider the heat conduction phenomenon caused by the contact between the water body and the target, providing a physical model for simulating the thermal characteristics of the target under a water surface background, and improving the realism of the simulation of the thermal characteristics of the target under a water surface background.
[0005] To achieve the above objectives, the present invention provides a method for generating an integrated mesh model of the target and the water surface, comprising:
[0006] Construct a target mesh model, a water surface mesh model, and a spatial coordinate system to obtain the vertex coordinates of the target mesh and the water surface mesh; the XOY plane of the spatial coordinate system is the plane where the water surface mesh model is located;
[0007] Determine the boundary vertices of the bottom grid of the target based on the vertex coordinates of the target grid;
[0008] Obtain the positional relationship between the water surface mesh vertices within the rectangular area and the boundary vertices of the target bottom mesh to determine the water surface mesh vertices near the target bottom; the target bottom mesh is located inside the rectangular area.
[0009] Connect the vertices of the water surface mesh near the bottom of the target with the boundary vertices of the bottom mesh of the target to generate an integrated target-water surface mesh model.
[0010] In one possible design, determining the boundary vertices of the target bottom mesh includes:
[0011] Determine the vertices of the bottom grid of the target based on the vertex coordinates of the target grid;
[0012] Determine the boundary vertices of the bottom grid of the target based on the vertex coordinates of the bottom grid of the target.
[0013] In one possible design, determining the vertices of the target bottom mesh includes:
[0014] Based on the coordinates of the target grid vertices, find the vertex with the smallest Z-coordinate among the target grid vertices, which is the vertex of the bottom grid of the target.
[0015] In one possible design, the boundary vertices of the target bottom mesh are determined based on the vertex coordinates of the target bottom mesh, including:
[0016] Define the vertex of the bottom mesh of the target with the smallest X and Y coordinates as the first boundary vertex A1;
[0017] Starting from the first boundary vertex, draw rays to all remaining vertices of the target bottom grid in sequence. The vertex of the target bottom grid corresponding to the ray with the smallest angle with the X-axis is the second boundary vertex A2.
[0018] Starting from the second boundary vertex A2, draw ray L1 to the first boundary vertex A1. Starting from the second boundary vertex A2, draw rays to all remaining vertices of the target bottom grid in sequence. The vertex of the target bottom grid corresponding to the ray with the largest angle to ray L1 is the third boundary vertex A3. By doing so, all boundary vertices of the target bottom grid can be determined.
[0019] In one possible design, after determining all boundary vertices of the target bottom mesh, the following steps are also included:
[0020] Remove all vertices from the bottom mesh of the target except for the boundary vertices.
[0021] In one possible design, determining the water surface mesh vertices near the bottom of the target includes:
[0022] Obtain the positional relationship between all water surface mesh vertices within the rectangular area and the boundary vertices of the target bottom mesh, in order to determine the water surface mesh vertices that do not overlap with the target bottom mesh;
[0023] Calculate the Euclidean distance between the water surface grid vertex that does not overlap with the bottom grid of the target and any boundary vertex of the bottom grid of the target. The water surface grid vertex with the smallest Euclidean distance is the water surface grid vertex that is closest to the bottom of the target.
[0024] In one possible design, determining the water surface mesh vertices that do not overlap with the target bottom mesh includes:
[0025] Select all water surface grid vertices within the rectangular area, draw a ray along the X-axis or Y-axis of the spatial coordinate system, and calculate the number of intersections of each ray with the polygon formed by the boundary vertices of the target bottom grid. If the number of intersections is odd, remove the water surface grid vertices; if the number of intersections is even, retain the water surface grid vertices, thus obtaining water surface grid vertices that do not overlap with the target bottom grid.
[0026] In one possible design, when drawing rays from the vertices of the water surface grid within a rectangular area towards the X-axis, the coordinates of the intersection points are calculated using the following formula:
[0027]
[0028] Among them, (x u ,y u Let (x) be the coordinates of the intersection point u, and (x) be the coordinates of the intersection point u. c ,y c Let (x) be the coordinates of vertex c, and (x) be the coordinates of vertex c. d ,y d Let (x) be the coordinates of vertex d, and (x) be the coordinates of vertex d. t ,y t Let ) be the coordinates of vertex t; where vertex t is any water surface grid vertex within the rectangular region, and vertices c and d are the two boundary vertices of the edge of the polygon that intersects with the ray, respectively.
[0029] When drawing rays from the vertices of the water surface grid within a rectangular area towards the Y-axis, the coordinates of the intersection points are calculated using the following formula:
[0030]
[0031]
[0032] Among them, (x v ,y v Let (x) be the coordinates of the intersection point v, and (x) be the coordinates of the intersection point v. a ,y a Let (x) be the coordinates of vertex a, and (x) be the coordinates of vertex a. b ,y b Let (x) be the coordinates of vertex b, and (x) be the coordinates of vertex b. t ,y t Let t be the coordinates of vertex t; vertex t is any water surface grid vertex within the rectangular region, and vertices a and b are the two boundary vertices of the edges of the polygon that intersect with the ray.
[0033] In one possible design, generating the target-surface integrated mesh model includes:
[0034] Connect the vertices of the water surface grid near the bottom of the target and the boundary vertices of the bottom grid of the target.
[0035] A water surface grid vertex near the bottom of the target is connected to the boundary vertices of the two target bottom grids with the smallest Euclidean distance; and / or
[0036] Two water surface grid vertices near the bottom of the target are connected to the boundary vertex of the bottom grid of the target with the smallest Euclidean distance.
[0037] In one possible design, the length of the water surface mesh model is 5 times the length of the target mesh model; the width of the water surface mesh model is 5 times the width of the target mesh model; and the mesh sizes of the water surface mesh model and the target mesh model are the same.
[0038] Compared with the prior art, the present invention has at least the following beneficial effects:
[0039] This invention uses the geometric mesh of the target and water surface three-dimensional model as a basis, and regenerates the triangular mesh at the intersection of the target and the water surface based on the position of the mesh vertex. This achieves the integrated connection between the water surface mesh and the target mesh, and provides a finite element mesh model for the heat conduction calculation of the side of the target and the water body. It comprehensively considers the heat transfer model of the water surface and the target, and improves the realism of the target thermal characteristics simulation under the background of the water surface. Attached Figure Description
[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0041] Figure 1 This is a flowchart of the process for generating an integrated mesh model of the target and the water surface according to the present invention;
[0042] Figure 2 This is the target mesh model of the present invention;
[0043] Figure 3 This is the water surface grid model of the present invention;
[0044] Figure 4 This is a schematic diagram of the polygon formed by the boundary vertices of the bottom mesh of the target in the target mesh model of the present invention;
[0045] Figure 5 This is a schematic diagram of the rectangular region B of the water surface grid of the present invention;
[0046] Figure 6 This is a schematic diagram of the rectangular region C of the water surface grid of the present invention;
[0047] Figure 7This is a schematic diagram showing the positional relationship between the intersection points of the rays drawn from the vertices of the water surface grid and the polygons in this invention;
[0048] Figure 8 The objective of this invention is an integrated grid model of the water surface. Detailed Implementation
[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0050] like Figure 1 As shown, this invention provides a method for generating an integrated mesh model of a target and a water surface, comprising:
[0051] Construct a target mesh model, a water surface mesh model, and a spatial coordinate system to obtain the vertex coordinates of the target mesh and the water surface mesh; the XOY plane of the spatial coordinate system is the plane where the water surface mesh model is located;
[0052] Determine the boundary vertices of the bottom grid of the target based on the vertex coordinates of the target grid;
[0053] Obtain the positional relationship between the water surface mesh vertices within the rectangular area and the boundary vertices of the target bottom mesh to determine the water surface mesh vertices near the target bottom; the target bottom mesh is located inside the rectangular area.
[0054] Connect the vertices of the water surface mesh near the bottom of the target with the boundary vertices of the bottom mesh of the target to generate an integrated target-water surface mesh model.
[0055] This invention uses the geometric mesh of the target and water surface three-dimensional model as a basis, and regenerates the triangular mesh at the intersection of the target and the water surface based on the position of the mesh vertex. This achieves the integrated connection between the water surface mesh and the target mesh, and provides a finite element mesh model for the heat conduction calculation of the side of the target and the water body. It comprehensively considers the heat transfer model of the water surface and the target, and improves the realism of the target thermal characteristics simulation under the background of the water surface.
[0056] This invention imports the acquired target geometric model (*.iges format) into the Hypermesh mesh generation software, and performs mesh generation of the target according to the detection resolution to form a target mesh model; this invention selects triangle as the mesh type, and the resulting target mesh model is a triangular mesh model (e.g., Figure 2(As shown); To facilitate subsequent processing, the vertices and triangle elements of the target triangular mesh model are numbered. For vertices, node1 is numbered in the order of 1, 2, 3... to ensure that each vertex has a unique number; for triangle elements, elem1 is numbered in the order of 1, 2, 3... to ensure that each element has a unique number.
[0057] Considering the effects of occlusion and heat conduction on the target and water surface, a geometric planar model of the water surface (*.iges format) with dimensions five times that of the target is constructed. Similarly, the water surface mesh is generated using HyperMesh software with triangular meshes, maintaining the same mesh scale as the hull mesh. To facilitate subsequent meshing at the intersection of the water surface mesh and the bottom vertex of the target, right-angled triangles are used for the water surface mesh, resulting in a triangular water surface mesh model (e.g., Figure 2 (As shown); further, the vertices and triangular facets of the triangular mesh on the water surface are numbered. For vertices, node2 is numbered in the order of 1, 2, 3... to ensure that each vertex has a unique number; for triangular facets, elem2 is numbered in the order of 1, 2, 3... to ensure that each facet has a unique number.
[0058] In some embodiments, determining the boundary vertices of the target bottom mesh includes:
[0059] Determine the vertices of the bottom grid of the target based on the vertex coordinates of the target grid;
[0060] Determine the boundary vertices of the bottom grid of the target based on the vertex coordinates of the bottom grid of the target.
[0061] In some embodiments, determining the vertices of the target bottom mesh includes:
[0062] Based on the coordinates of the target grid vertices, find the vertex with the smallest Z-coordinate among the target grid vertices, which is the vertex of the bottom grid of the target.
[0063] This invention constructs a spatial coordinate system. In order to better obtain the coordinates of all grid vertices in the target grid and the water surface grid, the plane where the water surface grid is located is used as the XOY plane of the spatial coordinate system. The vertex corresponding to the minimum Z coordinate Zmin in the target model is found, which is the vertex of the bottom grid of the target. The number of vertices corresponding to the minimum Z coordinate Zmin in the target model is counted, and the number of the vertex corresponding to the bottom grid of the target is recorded.
[0064] In some embodiments, determining the boundary vertices of the target bottom grid based on the vertex coordinates of the target bottom grid includes:
[0065] Define the vertex of the bottom mesh of the target with the smallest X and Y coordinates as the first boundary vertex A1;
[0066] Starting from the first boundary vertex, draw rays to all remaining vertices of the target bottom grid in sequence. The vertex of the target bottom grid corresponding to the ray with the smallest angle with the X-axis is the second boundary vertex A2.
[0067] Starting from the second boundary vertex A2, draw ray L1 to the first boundary vertex A1. Starting from the second boundary vertex A2, draw rays to all remaining vertices of the target bottom grid in sequence. The vertex of the target bottom grid corresponding to the ray with the largest angle to ray L1 is the third boundary vertex A3. By doing so, all boundary vertices of the target bottom grid can be determined.
[0068] In some embodiments, after determining all boundary vertices of the target bottom mesh, the method further includes:
[0069] Remove all vertices from the bottom mesh of the target except for the boundary vertices.
[0070] To create an integrated target-water surface mesh model, after confirming the vertices of the bottom mesh of the target, it is necessary to further confirm the boundary vertices of the bottom mesh of the target and delete all vertices in the bottom mesh of the target except for the boundary vertices; the specific process is as follows:
[0071] Find the first boundary vertex: First, define the vertex with the minimum X and Y coordinates among the vertices of the bottom grid of the target as the first boundary vertex, denoted as A1;
[0072] Find the second boundary vertex: Starting from the boundary vertex A1, traverse all vertices of the bottom grid of the target and draw rays. Find the ray with the smallest angle with the X-axis. The vertex corresponding to this ray (except A1) is the second boundary vertex, denoted as A2.
[0073] Find the third boundary vertex: Based on the boundary vertices A1 and A2, find the next boundary vertex A3. Starting from the second boundary vertex A2, draw a ray L1 to the first boundary vertex A1. Starting from the second boundary vertex A2, draw rays (L2, L3, L4...) to all the remaining vertices of the target bottom grid in sequence. The vertex of the target bottom grid that has the largest angle with ray L1 among the resulting rays (L2, L3, L4...) is the third boundary vertex A3.
[0074] Search for the remaining boundary vertices in the above order until the original boundary vertex A1 is found again. Then, export the boundary vertices in order and label them as vertices A1, A2, A3, etc. Delete the remaining vertices of the bottom mesh of the target.
[0075] In some embodiments, determining the water surface grid vertices near the bottom of the target includes:
[0076] Obtain the positional relationship between all water surface mesh vertices within the rectangular area and the boundary vertices of the target bottom mesh, in order to determine the water surface mesh vertices that do not overlap with the target bottom mesh;
[0077] Calculate the Euclidean distance between the water surface grid vertex that does not overlap with the bottom grid of the target and any boundary vertex of the bottom grid of the target. The water surface grid vertex with the smallest Euclidean distance is the water surface grid vertex that is closest to the bottom of the target.
[0078] In some embodiments, determining the water surface grid vertices that do not overlap with the target bottom grid includes:
[0079] Select all water surface grid vertices within the rectangular area, draw a ray along the X-axis or Y-axis of the spatial coordinate system, and calculate the number of intersections of each ray with the polygon formed by the boundary vertices of the target bottom grid. If the number of intersections is odd, remove the water surface grid vertices; if the number of intersections is even, retain the water surface grid vertices, thus obtaining water surface grid vertices that do not overlap with the target bottom grid.
[0080] It should be noted that after removing the water surface vertices that overlap with the target bottom grid, the process also includes comparing the coordinates of the water surface grid vertices remaining within the rectangular area with the boundary vertices of the target bottom grid. If the coordinates are the same, then the water surface grid vertex is also a vertex that overlaps with the target bottom grid, and this water surface grid vertex is removed.
[0081] It should be noted that the present invention can also draw rays in any direction in space to obtain the result of the number of intersection points; in order to facilitate the calculation of the coordinates of the intersection points, the present invention selects to draw a ray along the X-axis direction (positive or negative X-axis direction) or Y-axis direction (positive or negative Y-axis direction) of the spatial coordinate system, and determines the number of intersection points of each ray with the polygon formed by the boundary vertices of the bottom grid of the target by calculating the coordinates of the intersection points.
[0082] In some embodiments, when a ray is drawn from the vertex of the water surface grid within a rectangular area towards the X-axis, the coordinates of the intersection point are calculated using the following formula:
[0083]
[0084] Among them, (x u ,y u Let (x) be the coordinates of the intersection point u, and (x) be the coordinates of the intersection point u. c ,y c Let (x) be the coordinates of vertex c, and (x) be the coordinates of vertex c. d ,y d Let (x) be the coordinates of vertex d, and (x) be the coordinates of vertex d. t ,y tLet ) be the coordinates of vertex t; where vertex t is any water surface grid vertex within the rectangular region, and vertices c and d are the two boundary vertices of the edge of the polygon that intersects with the ray, respectively.
[0085] When drawing rays from the vertices of the water surface grid within a rectangular area towards the Y-axis, the coordinates of the intersection points are calculated using the following formula:
[0086]
[0087]
[0088] Among them, (x v ,y v Let (x) be the coordinates of the intersection point v, and (x) be the coordinates of the intersection point v. a ,y a Let (x) be the coordinates of vertex a, and (x) be the coordinates of vertex a. b ,y b Let (x) be the coordinates of vertex b, and (x) be the coordinates of vertex b. t ,y t Let t be the coordinates of vertex t; vertex t is any water surface grid vertex within the rectangular region, and vertices a and b are the two boundary vertices of the edges of the polygon that intersect with the ray.
[0089] To determine the water surface grid vertices near the bottom of the target, this invention defines the minimum and maximum values of the X-coordinate and the Y-coordinate in the bottom grid of the target, denoted as Xsmin, Xsmax, Ysmin, and Ysmax, respectively. A rectangular region B is constructed using the vertex with coordinates (Xsmin, Ysmin) and the two vertices with coordinates (Xsmax, Ysmax). Figure 5 ), where the vertex with coordinates (Xsmin, Ysmin) is the lower left vertex of rectangular region B, and the vertex with coordinates (Xsmax, Ysmax) is the upper right vertex of rectangular region B; further, for the vertices surrounding rectangular region B, find the water surface vertex grid closest to rectangular region B to form rectangular region C (e.g. Figure 6 Define the coordinates of the lower left vertex of rectangular region C as (Xwmin, Ywmin) and the coordinates of the lower right vertex as (Xwmax, Ywmax); the coordinates of the lower left and lower right vertices of rectangular region B and rectangular region C satisfy the following relationship:
[0090] Xwmin≤Xsmin;
[0091] Ywmin≤Ysmin;
[0092] Xwmax ≥ Xsmax;
[0093] Ywmax ≥ Ysmax.
[0094] Select a water surface vertex located within a rectangular region C. Draw rays along the X-axis (positive or negative) or Y-axis (positive or negative) of the spatial coordinate system. Calculate the number of intersection points between each ray and all boundary vertices of the target bottom grid. If the number of intersection points is odd, it means the water surface vertex is inside the polygon, and thus overlaps with the target bottom grid; remove the water surface vertex. If the number of intersection points is even, it means the water surface vertex is outside the polygon; retain the water surface grid vertex. Further, compare the coordinates of the retained water surface grid vertices within the rectangular region with the boundary vertices of the target bottom grid. If the coordinates are the same, the water surface grid vertex also overlaps with the target bottom grid; remove this water surface grid vertex. The remaining water surface grid vertices are those that do not overlap with the target bottom grid.
[0095] This refers to the water surface grid vertices that do not overlap with the bottom grid of the target.
[0096] The following explains the logical correctness of this method:
[0097] (1) If the vertex of the water surface grid is inside the polygon, a ray is drawn from the vertex in the positive X-axis direction or the negative Y-axis direction. The ray will exit the polygon and intersect the edge of the polygon only once, that is, form one intersection point.
[0098] (2) For water grid vertices located outside the polygon, if a ray is drawn from that vertex in the positive X-axis direction or the negative Y-axis direction, the following two cases will exist:
[0099] ① The ray does not enter the polygon and intersects the polygon 0 times, that is, it forms 0 intersection points;
[0100] ②When a ray passes through a polygon, it will enter the polygon once and exit the polygon once, intersecting the polygon twice, thus forming two intersection points.
[0101] By determining the number of intersection points, it can be concluded whether a vertex is inside the polygon.
[0102] by Figure 7 For example, when a ray is drawn from the vertex of the water surface within a rectangular region C towards the positive X-axis, the coordinates of the intersection point u (x...) are... u ,y u The calculation method is as follows:
[0103]
[0104]
[0105] Among them, (x u ,y u Let (x) be the coordinates of the intersection point u, and (x) be the coordinates of the intersection point u.c ,y c Let (x) be the coordinates of vertex c, and (x) be the coordinates of vertex c. d ,y d Let (x) be the coordinates of vertex d, and (x) be the coordinates of vertex d. t ,y t Let be the coordinates of vertex t; where vertex t is the water surface grid vertex within the rectangular region, and vertices c and d are the two boundary vertices of the edges of the polygon that intersect with the ray.
[0106] When a ray is drawn from the vertex of the water surface within the rectangular region C towards the negative Y-axis, the coordinates (x, y) of the intersection point v are... v ,y v The calculation method is as follows:
[0107] When drawing rays from the vertices of the water surface grid within a rectangular area towards the Y-axis, the coordinates of the intersection points are calculated using the following formula:
[0108]
[0109]
[0110] Among them, (x v ,y v Let (x) be the coordinates of the intersection point v, and (x) be the coordinates of the intersection point v. a ,y a Let (x) be the coordinates of vertex a, and (x) be the coordinates of vertex a. b ,y b Let (x) be the coordinates of vertex b, and (x) be the coordinates of vertex b. t ,y t ) represents the coordinates of vertex t; vertex t is the water surface grid vertex within the rectangular region, and vertices a and b are the two boundary vertices of the edges of the polygon that intersect with the ray.
[0111] Furthermore, taking the first boundary vertex A1 of the target bottom mesh as an example, calculate the Euclidean distance between all water surface mesh vertices that do not overlap with the target bottom mesh and the first boundary vertex A1. The water surface mesh vertex corresponding to the smallest Euclidean distance is the water surface mesh vertex adjacent to the target bottom, denoted as C1. Perform the above calculation on all boundary vertices of the target bottom mesh to obtain all water surface mesh vertices adjacent to the target bottom, denoted as C1, C2, C3, etc. in sequence.
[0112] In some embodiments, generating a target-water surface integrated mesh model includes:
[0113] Connect the vertices of the water surface grid near the bottom of the target and the boundary vertices of the bottom grid of the target.
[0114] A water surface grid vertex near the bottom of the target is connected to the boundary vertices of the two target bottom grids with the smallest Euclidean distance; and / or
[0115] Two water surface grid vertices near the bottom of the target are connected to the boundary vertex of the bottom grid of the target with the smallest Euclidean distance.
[0116] For the mesh generation of the interface between the target and the water surface, it is necessary to include at least one bottom target mesh vertex and one water surface mesh vertex. To avoid duplicate connections between vertices and ensure mesh generation quality, connections are made based on the Euclidean distance between the target boundary vertex and the adjacent bottom water surface mesh vertex. The generation of triangular meshes includes the following two cases:
[0117] (1) Connect one bottom vertex of the ship with the two nearest (smallest Euclidean distance) water surface vertices to form a triangular mesh;
[0118] (2) Connect the two bottom vertices of the ship with the nearest (smallest Euclidean distance) water surface vertex to form a triangular mesh;
[0119] The newly generated triangular facets and vertices are numbered to form an integrated mesh model of the target and the water surface, as shown below. Figure 8 As shown.
[0120] In some embodiments, the length of the water surface mesh model is 5 times the length of the target mesh model; the width of the water surface mesh model is 5 times the width of the target mesh model; and the mesh sizes of the water surface mesh model and the target mesh model are the same.
[0121] This invention ultimately generates an integrated target-water surface mesh model, which can be applied to consider the heat conduction phenomenon caused by the contact between the water body and the target, providing a physical model for simulating the thermal characteristics of the target under a water surface background, and improving the realism of the simulation of the thermal characteristics of the target under a water surface background.
[0122] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.
[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for generating an integrated mesh model of a target and a water surface, characterized in that, include: Construct a target mesh model, a water surface mesh model, and a spatial coordinate system to obtain the vertex coordinates of the target mesh and the water surface mesh; the XOY plane of the spatial coordinate system is the plane where the water surface mesh model is located; The target mesh model is a triangular mesh model; the water surface mesh model is divided using right-angled triangular meshes. Determine the vertices of the bottom grid of the target based on the vertex coordinates of the target grid; Determine the boundary vertices of the target's bottom grid based on the vertex coordinates of the bottom grid. Define the vertex of the bottom mesh of the target with the smallest X and Y coordinates as the first boundary vertex A1; Starting from the first boundary vertex, draw rays to all remaining vertices of the target bottom grid in sequence. The vertex of the target bottom grid corresponding to the ray with the smallest angle with the X-axis is the second boundary vertex A2. Starting from the second boundary vertex A2, draw ray L1 to the first boundary vertex A1. Starting from the second boundary vertex A2, draw rays to all remaining vertices of the target bottom grid in sequence. The vertex of the target bottom grid corresponding to the ray with the largest angle to ray L1 is the third boundary vertex A3. And so on, all boundary vertices of the target bottom grid can be determined. Obtain the positional relationship between all water surface mesh vertices within the rectangular area and the boundary vertices of the target bottom mesh, in order to determine the water surface mesh vertices that do not overlap with the target bottom mesh; Calculate the Euclidean distance between the water surface grid vertex that does not overlap with the target bottom grid and any boundary vertex of the target bottom grid. The water surface grid vertex with the smallest Euclidean distance is the water surface grid vertex that is closest to the target bottom. The target bottom grid is located inside the rectangular region. Select all water surface grid vertices within the rectangular area, draw a ray along the X-axis or Y-axis of the spatial coordinate system, and calculate the number of intersections of each ray with the polygon formed by the boundary vertices of the bottom grid of the target. If the number of intersections is odd, remove the vertices of the water surface grid. If the number of intersection points is even, the water surface grid vertices are retained, resulting in water surface grid vertices that do not overlap with the bottom grid of the target. A target-water integrated mesh model is generated by connecting the vertices of the water surface mesh near the bottom of the target and the boundary vertices of the bottom mesh of the target. A water surface grid vertex near the bottom of the target is connected to the boundary vertices of the two target bottom grids with the smallest Euclidean distance; and / or Two water surface grid vertices near the bottom of the target are connected to the boundary vertex of the bottom grid of the target with the smallest Euclidean distance.
2. The generation method according to claim 1, characterized in that, The vertices of the bottom mesh of the target are determined as follows: Based on the coordinates of the target mesh vertices, find the vertex with the smallest Z-coordinate among the target mesh vertices, which is the vertex of the bottom mesh of the target.
3. The generation method according to claim 1, characterized in that, After determining all boundary vertices of the target bottom mesh, the process also includes: Remove all vertices of the target bottom mesh except for the boundary vertices.
4. The generation method according to claim 1, characterized in that, When a ray is drawn from the vertex of the water surface grid within the rectangular area towards the X-axis, the coordinates of the intersection point are calculated using the following formula: ， ;in, Let u be the coordinates of the intersection point. Let c be the coordinates. Let d be the coordinates of vertex d. Let be the coordinates of vertex t; where vertex t is any water surface grid vertex within the rectangular region, and vertices c and d are the two boundary vertices of the edge intersecting the ray in the polygon, respectively. When a ray is drawn from the vertex of the water surface grid within the rectangular area towards the Y-axis, the coordinates of the intersection point are calculated using the following formula: ， ； in, Let v be the coordinates of the intersection point. Let a be the coordinates of vertex a. Let b be the coordinates of vertex b. Let be the coordinates of vertex t; vertex t is any water surface grid vertex within the rectangular region, and vertices a and b are the two boundary vertices of the edges of the polygon that intersect with the ray.
5. The generation method according to claim 1, characterized in that, The length of the water surface mesh model is 5 times the length of the target mesh model; the width of the water surface mesh model is 5 times the width of the target mesh model; the mesh size of the water surface mesh model and the target mesh model are the same.