A method for parametric modeling of an interactive continuous pavement road three-dimensional model

Abstract

The application discloses a kind of interactive continuous pavement road three-dimensional model parameterization modeling method, the method includes: input road design three key points A, B, C, pavement width w, normal vector, interpolation resolution r, pavement thickness d and texture width t, through algorithm calculation generation curve road two sides pavement coordinates, calculate interpolation coordinate, calculate road triangular net model, calculate texture coordinate and carry out texture mapping, obtain anchor point position and generate guardrail model, so that it keeps the continuity of the pavement generated when road parameterization modeling, especially in horizontal ground turning, uphill and downhill turning, high-low difference folding ramp and the coherence of the pavement in other parts.

Description

Technical Field

[0001] This invention relates to the establishment of three-dimensional models of continuous road surfaces, and in particular to parametric modeling of continuous road surfaces in road design when encountering situations such as elevation differences and large turning radii. Background Technology

[0002] With the rapid development of computer graphics, 3D simulation technology, virtual reality technology, and network communication technology, traditional two-dimensional electronic maps have been injected with new vitality, and 3D electronic maps carried on the Internet are becoming an important direction for the development of electronic maps. 3D maps enable richer interactions and more sophisticated rendering techniques, providing greater possibilities for related products. However, in practice, when parametrically modeling roads during the planning stage, the road model is constructed by stitching together multiple micro-element model bodies. This leads to a series of discontinuous problems in road surface design when there are significant differences in elevation or large turning radii, such as cliff edges, elevation misalignment, and missing corner edges at turns. Furthermore, when adjusting the planned road alignment, the aforementioned problems may occur even with already modeled continuous road surfaces. Overall, the accuracy of the 3D road model is poor, making it difficult to accurately reproduce the road design results. Summary of the Invention

[0003] To overcome the shortcomings of parametric modeling of roads during the planning stage, this invention aims to maintain the continuity of the generated road surface during parametric modeling, especially the continuity of the road surface in areas such as turns on level ground, turns on inclines and declines, and folded ramps with elevation differences.

[0004] The technical solution adopted by this invention to solve its technical problem is: A method for parametric modeling of an interactive continuous road surface 3D model, the method comprising the following steps; S1, input the three key points of road design A, B, and C, road width w, and normal vector. Interpolation resolution r, road surface thickness d, and texture width t; S2, calculate and generate the coordinates of the left side of the road surface on the curve; S3, the same algorithm is used to calculate the right-side coordinates of the curve; S4. Calculate the interpolated coordinates of the continuous road surface of the straight segments on the left and right sides of segment ABC based on the interpolation resolution r parameter. S5. Calculate the road triangulation model based on the road thickness d parameter and the road interpolation coordinates; S6, Calculate the road surface texture coordinates; S7, perform road surface texture mapping coordinate by coordinate; S8. Based on the length of the road edge line, obtain the position of the guardrail anchor point at a fixed distance. S9, Generate the guardrail model coordinate by coordinate; The calculation of the left-side coordinates of the road surface on the curve includes the following steps: a) Connect the key points A, B, and C of the road to obtain the vector. , ; b) Calculate separately , With normal vector The perpendicular vector, with a length equal to the road width w, is used to obtain the road's outward parallel line; c) Calculation , The corresponding extension points Ax, ABx, Cx, BCx on the parallel line of the road's outward expansion; d) Calculate the vectors corresponding to points ABx and Ax. The vectors corresponding to points Cx and BCx ; e) Calculation , The perpendicular bisector of the road, with the road width w as its length, determines the center OL of the spherical interpolation. f) Construct ray R1 from Ax and ABx and ray R2 from BCx and Cx; g) Calculate the two points PS and PE that are closest to the center point OL of spheres R1 and R2; h) Based on the interpolation resolution r parameter, perform Slerp spherical linear interpolation with OL as the center, PS as the starting point, and PE as the ending point to calculate the interpolation points on the curve. Starting from the starting point Ax, push them onto the stack sequentially until Cx is pushed onto the stack to obtain the coordinates of the entire left curve; The calculation of road surface texture coordinates includes the following steps: a) Calculate the length M of the road edge line based on the road edge lines obtained from S2 and S3; b) Calculate t1=M / t to obtain texture coordinates (s, t1). The left side of the road is denoted as 0, and the right side is denoted as 1.

[0005] Furthermore, the road surface texture map has different materials, patterns, or colors.

[0006] Furthermore, the interpolation resolution r is adjusted according to different sections of the road.

[0007] Furthermore, the road edge line can be a straight segment, an arc segment, or a compound curve.

[0008] Furthermore, the guardrail models described herein have different shapes, sizes, and materials.

[0009] Furthermore, the road triangulation model employs different triangulation methods and partitioning strategies.

[0010] Furthermore, generating the guardrail model coordinate by coordinate includes the following steps: a) Calculate the position and orientation of each guardrail component based on the location of the guardrail anchor points; b) Draw the basic shape of the guardrail based on the position and orientation of the guardrail components; c) Based on the basic shape of the drawn fence, generate the actual form of the fence according to the fence material and its characteristics, including the size and texture of the fence; d) Generate a 3D model of the guardrail based on its actual shape for rendering and demonstration.

[0011] The beneficial effects of this invention are: 1. This invention constructs a continuous road surface, especially in the case of curves, the three-dimensional road model has high accuracy and good visualization effect, and truly restores the design results; 2. The input parameters are simple and clear, and the parameters can be adjusted in real time according to the project during road planning and selection, which can quickly respond to design changes. Attached Figure Description

[0012] 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 only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of key points for road generation in a parametric modeling method for interactive continuous road surface three-dimensional models according to this application. Figure 2 This is a schematic diagram illustrating the generation of outward parallel lines in a method for parametric modeling of an interactive continuous road surface 3D model according to this application. Figure 3 This is a schematic diagram of the interpolation center for calculating the perpendicular bisector of a parametric modeling method for an interactive continuous road surface 3D model according to this application. Figure 4 This is a schematic diagram illustrating the interpolation start and stop point calculation of a method for parametric modeling of an interactive continuous road surface three-dimensional model according to this application. Figure 5 This is a schematic diagram of spherical interpolation for a method of parametric modeling of an interactive continuous road surface three-dimensional model according to this application; Figure 6 This is a schematic diagram illustrating the generation of curved road surfaces in a parametric modeling method for interactive continuous road surface three-dimensional models according to this application. Figure 7 This is a schematic diagram of a road 3D model illustrating an interactive continuous road surface 3D model parametric modeling method according to this application; Figure 8 This is a flowchart illustrating the calculation process of a method for parametric modeling of an interactive continuous road surface 3D model according to this application. Detailed Implementation

[0014] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. The components of the embodiments of this disclosure described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0015] Therefore, the following detailed description of the embodiments of the present disclosure provided in the accompanying drawings is not intended to limit the scope of the claimed disclosure, but merely to illustrate selected embodiments of the disclosure and is used only for explanation and interpretation. All other embodiments obtained by those skilled in the art based on the embodiments of the present disclosure without inventive effort are within the scope of protection of this disclosure.

[0016] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0017] This invention is based on a three-dimensional geographic information system. Within this system, coordinate systems can be categorized into geocentric coordinate systems, geographic coordinate systems, and local coordinate systems based on different observation spaces. The geocentric coordinate system is a Cartesian coordinate system with the Earth's center as the origin and meters as the unit. Geographic coordinates are polar coordinates represented by longitude, latitude, and altitude, using WGS84 sphere parameters and representing rotation using the northeast-northeast sky. Vector operations in this invention follow the right-hand rule. The local coordinate system uses a specific geographic coordinate point as a reference, projecting other geographic coordinate points onto that point's coordinate space. Local coordinates also follow the right-hand rule, following a T-Pose coordinate system for character modeling, where the character's right hand is the x-axis, the front facing the y-axis, and the direction above the head is the z-axis. In most cases, the surface of the road surface is in the same direction as or coplanar with the Earth's normal at that point. This surface is perpendicular to the tangent plane at that point, and its normal is the x-axis. The road surface slope cannot exceed 90 degrees; however, this does not apply to curves.

[0018] Parameter description: Interactive continuous road input parameters: road nodes, road width, road texture material, interpolation resolution, guardrail type, etc.

[0019] This method, based on 3D vector computation and spherical interpolation, aims to ensure road surface continuity in 3D scenes, particularly in road design during the planning phase when encountering elevation differences and large turning radii. It proposes an interactive curve interpolation algorithm to obtain the coordinates of road curves. This algorithm is symmetric, using the same algorithm to obtain coordinates on both sides of the road. Based on the curve coordinates, texture coordinates and guardrail coordinates are calculated to complete the construction of a continuous 3D road surface model. The specific steps of this method are as follows: Step 1: Input parameters. Input three key points for road design, labeled A, B, and C in order, along with the road width w and the normal vector. Interpolation resolution r (curve point density), road surface thickness d, and texture width t.

[0020] Step 2: Generating the road surface coordinates for the curve. When calculating the curve, the point is projected onto point B as a reference point in the local coordinate space. This algorithm is symmetrical; the same algorithm is used to generate coordinates on both sides of the road. Taking the algorithm on the left side of the road as an example: a) Connect the key points A, B, and C of the road to obtain the vector. , ,like Figure 1 ; b) Calculate separately , With normal vector The perpendicular vector, with a length equal to the road width w, is used to obtain the road's outward extension parallel lines, such as... Figure 2 As shown; c) Calculation , The corresponding extension points Ax, ABx, Cx, BCx on the parallel line of the road's outward expansion; d) Calculate the vectors corresponding to points ABx and Ax. The vectors corresponding to points Cx and BCx ; e) Calculation , The perpendicular bisector of the line, with the road width w as its length, determines the center OL of the spherical interpolation, as shown below. Figure 3 As shown; f) Construct ray R1 from Ax and ABx and ray R2 from BCx and Cx; g) Calculate the two points PS and PE that are closest to the center of the sphere OL for rays R1 and R2, such as... Figure 4 As shown; h) Based on the interpolation resolution r parameter, perform Slerp spherical linear interpolation with OL point as the center, PS as the starting point, and PE as the ending point, such as... Figure 5As shown, the interpolation points on the curve can be calculated. Starting from the starting point Ax, they are pushed onto the stack sequentially until Cx is pushed onto the stack, thus obtaining the coordinates of the entire left curve. Those skilled in the art will understand that the interpolation resolution r can be adjusted according to different sections of the road. Those skilled in the art will understand that, in summary, the calculation of the left side of both sides of the road can actually be summarized as follows: b) Calculate the outward parallel lines of the road based on the key points A, B, and C, and then calculate the points Ax, ABx, Cx, and BCx on these parallel lines; c) Calculate the vectors corresponding to points ABx, Ax and points Cx, BCx, and then calculate the perpendicular bisectors of these vectors. Determine the center OL of the spherical interpolation circle with the road width w as the length. d) Based on the interpolation resolution r parameter, slerp spherical linear interpolation is performed with OL point as the center, PS as the starting point, and PE as the ending point to calculate the interpolation points on the curve; Step 3: Calculate the coordinates of the right side of the curve using the above algorithm. Those skilled in the art will understand that there is no specific order for generating the coordinates of the left and right sides, as long as the generation is achieved. Step 4: Based on the interpolation resolution r parameter, calculate the interpolation coordinates of the continuous road surface of the straight segments on both sides of segment ABC. Those skilled in the art will understand that the interpolation resolution r can be adjusted according to different segments of the road. Step 5: Calculate the road triangulation model based on the road thickness d parameter and the road interpolation coordinates. Those skilled in the art will understand that the road triangulation model can be constructed using different triangulation methods and partitioning strategies. Step 6: Calculate the texture coordinates based on the calculated road edge line. Those skilled in the art will understand that the road edge line can be a straight line segment, an arc segment, or a composite curve.

[0021] a) Texture coordinates are calculated based on the road edge lines obtained by the curve generation algorithm described above, and are denoted as M; b) Calculate t1=M / t to obtain the texture coordinates (s, t1). The left side of the road is denoted as 0, and the right side is denoted as 1. Step 7: Based on the texture coordinates, perform road surface texture mapping coordinate by coordinate, such as... Figure 6 As shown; those skilled in the art will understand that the road surface texture map can be of different materials, patterns or colors.

[0022] Step 8: Based on the length of the road edge line, obtain the positions of the guardrail anchor points at fixed intervals; Step 9: Generate the guardrail model coordinate by coordinate, such as... Figure 7 As shown, those skilled in the art will understand that guardrail models can be of different shapes, sizes, and materials.

[0023] The method for generating a guardrail model based on guardrail coordinates includes the following steps: a) Calculate the position and orientation of each guardrail component based on the misalignment of the guardrail; b) Draw the basic shape of the guardrail based on the position and orientation of the guardrail components; c) Based on the basic shape of the drawn fence, generate the actual form of the fence according to the fence material and its characteristics, including the size and texture of the fence; d) Generate a 3D model of the guardrail based on its actual shape, which can be used for rendering and demonstration.

[0024] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for parametric modeling of interactive continuous road surface 3D models, characterized in that: The method includes the following steps; S1, input the three key points of road design A, B, and C, road width w, and normal vector. Interpolation resolution r, road surface thickness d, and texture width t; S2, calculate and generate the coordinates of the left side of the road surface on the curve; S3, the same algorithm is used to calculate the right-side coordinates of the curve; S4. Calculate the interpolated coordinates of the continuous road surface of the straight segments on the left and right sides of segment ABC based on the interpolation resolution r parameter. S5. Calculate the road triangulation model based on the road thickness d parameter and the road interpolation coordinates; S6, Calculate the road surface texture coordinates; S7, perform road surface texture mapping coordinate by coordinate; S8. Based on the length of the road edge line, obtain the position of the guardrail anchor point at a fixed distance. S9, Generate the guardrail model coordinate by coordinate; The calculation of the left-side coordinates of the road surface on the curve includes the following steps: a) Connect the key points A, B, and C of the road to obtain the vector. , ; b) Calculate separately , With normal vector The perpendicular vector, with a length equal to the road width w, is used to obtain the road's outward parallel line; c) Calculation , The corresponding extension points Ax, ABx, Cx, BCx on the parallel line of the road's outward expansion; d) Calculate the vectors corresponding to points ABx and Ax. The vectors corresponding to points Cx and BCx ; e) Calculation , The perpendicular bisector of the road, with the road width w as its length, determines the center OL of the spherical interpolation. f) Construct ray R1 from Ax and ABx and ray R2 from BCx and Cx; g) Calculate the two points PS and PE that are closest to the center point OL of spheres R1 and R2; h) Based on the interpolation resolution r parameter, perform Slerp spherical linear interpolation with OL as the center, PS as the starting point, and PE as the ending point to calculate the interpolation points on the curve. Starting from the starting point Ax, push them onto the stack sequentially until Cx is pushed onto the stack to obtain the coordinates of the entire left curve; The calculation of road surface texture coordinates includes the following steps: a) Calculate the length M of the road edge line based on the road edge lines obtained from S2 and S3; b) Calculate t1=M / t to obtain texture coordinates (s, t1). The left side of the road is denoted as 0, and the right side is denoted as 1.

2. The method for parametric modeling of an interactive continuous road surface three-dimensional model according to claim 1, characterized in that: The road surface texture map has different materials, patterns, or colors.

3. The method for parametric modeling of an interactive continuous road surface three-dimensional model according to claim 1, characterized in that: The interpolation resolution r is adjusted according to different sections of the road.

4. The method for parametric modeling of an interactive continuous road surface three-dimensional model according to claim 1, characterized in that: The road edge line can be a straight line segment, an arc segment, or a compound curve.

5. The method for parametric modeling of an interactive continuous road surface three-dimensional model according to claim 1, characterized in that: The guardrail models described have different shapes, sizes, and materials.

6. The method for parametric modeling of an interactive continuous road surface three-dimensional model according to claim 1, characterized in that: The road triangulation model described above employs different triangulation methods and partitioning strategies.

7. The method for parametric modeling of an interactive continuous road surface three-dimensional model according to claim 1, characterized in that: Generating a guardrail model coordinate by coordinate involves the following steps: a) Calculate the position and orientation of each guardrail component based on the location of the guardrail anchor points; b) Draw the basic shape of the guardrail based on the position and orientation of the guardrail components; c) Based on the basic shape of the drawn fence, generate the actual form of the fence according to the fence material and its characteristics, including the size and texture of the fence; d) Generate a 3D model of the guardrail based on its actual shape for rendering and demonstration.

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