A method and system for cutting slope intersections in a three-dimensional BIM model of a roadbed

Abstract

The present invention relates to the field of BIM and highway engineering, and in particular to a method and system for cutting slope intersections of a three-dimensional BIM model of a roadbed, the method comprising: S1 obtaining the slope sidelines of two intersecting routes, and connecting the coordinates of the outermost feature points of the slope sidelines of each route in a clockwise or counterclockwise order to form a closed curve; S2 generating the intersection area of ​​the two intersecting routes according to the closed curve; and using a line-line intersection algorithm to calculate the coordinates of the intersection points of the slope intersection within the intersection area; S3 cutting the route cross-section design line based on the coordinates of the intersection points of the slope intersection, and generating a three-dimensional model of the intersecting slopes. The intersection points obtained by the present invention are all accurate intersection points with negligible errors, and the slopes can be accurately cut, and the road surface effect presented in the field of BIM modeling is excellent.

Description

Technical Field

[0001] The invention relates to the field of BIM (Building Information System) and highway engineering, and in particular to a method and system for cutting slope intersections of a three-dimensional BIM model of a roadbed. Background Art

[0002] BIM is a digitized tool used in engineering design, construction and management based on three-dimensional digital technology. It is a computer-aided design based on three-dimensional graphics, object-oriented and architecture. The purpose of BIM modeling technology is to help achieve the integration of building information, from building design and construction to project completion.

[0003] One of the current applications of BIM technology in the field of highway engineering is rapid mold remodeling. During the mold remodeling process, the design data is obtained from the design drawings, the drawings are three-dimensionalized, and the horizontal, vertical and horizontal information of the roadbed and the structural information of bridges and tunnels are accurately expressed through the BIM model. The road major also enters the superelevation data provided by the design into a customized cross-section assembly with superelevation function to achieve accurate mold remodeling of the roadbed BIM model.

[0004] Conventional 3D BIM modeling methods for roadbeds usually involve the following steps: collecting relevant data for roadbed projects, including design drawings, terrain data, engineering specifications, and material information; using terrain data and survey data to create a terrain model for the roadbed; and based on the design drawings and specifications, creating a 3D model of the roadbed on the terrain model and establishing the roadbed’s basic structures, such as embankments, retaining walls, slopes, etc.

[0005] In the existing roadbed modeling methods, it is usually based on design drawings and specifications, with the help of three-dimensional high-precision aerial survey terrain, and the known road center line, roadbed width or roadbed shoulder line to determine the accurate distribution of each component of the roadbed model (such as median strip, earth shoulder, driving lane, shoulder wall, fill slope, embankment wall, ditch, cutting wall, excavation slope, etc.), and obtain the cross-sectional design results. By connecting the cross-sectional design results of adjacent key pile numbers, the three-dimensional model of the roadbed is obtained. After many years of engineering practice, this model basically meets the requirements of conventional highway design and rapid modeling, but it also has quite a few limitations. It is mainly reflected in the fact that the modeling details are not fine enough and the design results cannot be accurately and completely reflected in the three-dimensional scene. For example: slope intersection clipping problems, nose end modeling problems, etc.

[0006] In the field of highway design, the existing solution to the problem of slope intersection and cutting is to draw a two-dimensional cross-sectional design drawing through the Weidi design software, and then manually modify the slope of the cross-sectional design drawing through the cross-sectional design drawings of adjacent routes to make it generally reasonable.

[0007] The main problems with this method are:

[0008] (1) The calculated intersection is inaccurate. The two-dimensional cross-section line is directly extended to intersect with the center line of another route, and the cross-section line with the pile number corresponding to the intersection is placed on the same plane as the original cross-section line, and the intersection of the two cross-section lines is used as the approximate intersection. The schematic diagram of the approximate intersection is shown in Figure 1 As shown, line A and line B intersect. To perform slope intersection cutting, you need to find the intersection point first. Usually, the intersection point a in line A is extended perpendicular to the side line to produce a ray. The ray intersects the center line of line B at point b. The pile number of line B is found at point b. The cross-section design lines corresponding to the pile numbers are extracted respectively, and the intersection point is obtained directly from the two cross-section design lines. This method does not take into account the elevation difference or the curvature of line A and line B during calculation. The method of drawing an extension line from line A to find the intersection point and pile number of line B is only an approximate calculation (the actual pile number should be the pile number of point C). This method cannot accurately calculate the position where the cross-section line ends, and is an engineering approximation.

[0009] (2) Low efficiency. After placing two cross-section lines on the same plane, there is an approximate intersection. Designers need to manually add some design intentions before and after the approximate intersection to meet the needs, such as side ditches. This method requires manual modification of a large number of cross-section lines, requires the participation of a large number of designers, and is time-consuming and laborious.

[0010] In addition, in the field of roadbed 3D modeling, the existing rapid modeling methods mainly calculate a single route to obtain the cross-section design line. Since the cross-section design line is only calculated by its own latitude and terrain file and the terrain, and no intersection and clipping calculation is performed with other routes, there is no good way to solve the slope intersection and clipping problem when two or more routes are close and intersect.

[0011] like Figure 2 As shown, Figure 2 The situation that the intersection of two cross-section lines is used as the approximate intersection point, resulting in the deviation of the slope intersection cutting of the generated roadbed three-dimensional modeling, is given. Based on the existing technology, if accurate slope intersection cutting is to be achieved, a large amount of slope specific data needs to be obtained for calculation, and the efficiency of slope intersection cutting is low. Summary of the invention

[0012] The present invention proposes a method for cutting slope intersections in a three-dimensional BIM model of a roadbed, which aims to solve the problem of cutting slope intersections in the three-dimensional BIM modeling process of a highway engineering roadbed. The present invention can automatically, accurately and efficiently calculate the cutting points of the slope intersections, and automatically cut the cross-section lines. The invention can also be applied to accurate cutting of slope intersections during roadbed design.

[0013] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0014] A method for cutting slope intersections in a three-dimensional BIM model of a roadbed, comprising the following steps:

[0015] S1 obtains the slope edges of two intersecting routes, and connects the coordinates of the outermost feature points of the slope edges of each route in a clockwise or counterclockwise order to form a closed curve;

[0016] S2 generates the intersection area of ​​the two intersecting routes according to the closed curve; and calculates the coordinates of the intersection point of the slope intersection using the line-line intersection algorithm within the intersection area;

[0017] S3 cuts the route cross-section design line based on the coordinates of the intersection points of the slopes, and generates a three-dimensional model of the intersecting slopes.

[0018] As a preferred solution, the generated intersection area of ​​the two intersecting routes satisfies the following conditions:

[0019] For two intersecting closed curves, feature points adjacent to the intersection point on one of the closed curves are located outside and inside the closed region of the other closed curve, respectively.

[0020] As a preferred solution, the line-line intersection algorithm is used to calculate the intersection coordinates of the slope intersection, including: obtaining the characteristic points of the intersection area; arranging the characteristic points of the intersection area in ascending order of pile number, from the starting pile number to the ending pile number, and repeating the following steps: taking the cross-sectional line corresponding to the pile number of one of the routes as a reference, through the cross-sectional design line and the roadbed edge line of the other route, using the iterative calculation of geometric line-line intersection, to obtain the slope intersection coordinates of the two intersecting routes under the pile number.

[0021] As a preferred solution, obtaining the slope intersection coordinates of the two intersecting routes under the stake number specifically includes the following steps:

[0022] S21 obtains the current main line stake number of the main line, and takes the roadbed edge line feature point A corresponding to the current main line stake number as the starting point in the two-dimensional plane coordinate system from a vertical perspective, and extends the auxiliary line in a direction perpendicular to the main line edge line until the auxiliary line intersects the roadbed edge line of the secondary line at point B;

[0023] S22, on the line connecting point A and point B, with point A as the starting point, obtains point C with a horizontal offset x0, and obtains point C, draws a perpendicular line from point C to the roadbed edge line on the side of the secondary road, intersecting at point D, and obtains the secondary road pile number corresponding to point D;

[0024] S23 projects the cross-section design line at the stake number of point A of the main route and the cross-section design line at the stake number of point D of the secondary route onto the same two-dimensional plane, and obtains the intersection point E of the cross-section design lines of the main route and the secondary route;

[0025] S24 calculates the horizontal offset x1 of point E on the main route cross section based on point E, and calculates the horizontal offset difference Δ=x1-x0. If Δ is less than the specified threshold parameter x threshold , it is considered that point E is the final slope intersection point, otherwise, x1 is used to replace x0 and steps S22 to S24 are re-executed until Δ is less than the specified threshold parameter x threshold .

[0026] As a preferred solution, when point C is obtained for the first time, the horizontal offset x0 is half of the line connecting point A to point B.

[0027] As a preferred solution, the generating of the intersecting slope three-dimensional model comprises the following steps:

[0028] The points with the same feature number in the two cross sections are connected into a line. There are four feature points in the two lines connecting adjacent feature numbers, and there are four feature point coordinates for the four feature points. If two non-overlapping spatial triangular faces can be drawn and the four points are completely contained in the vertices, they are considered to be valid spatial triangular faces, and a three-dimensional face is constructed. The three-dimensional face is the three-dimensional model of the intersecting slope.

[0029] As a preferred solution, the types of roadbed include: median strip, earth shoulder, driving lane, earth shoulder, shoulder wall, fill slope, embankment wall, side ditch, cutting wall, and excavation slope.

[0030] As a preferred solution, in step S1, after obtaining the slope edges of two intersecting routes, a cross-sectional design line data array of each route is obtained, the array is composed of several cross-sectional design lines, a cross-sectional design line is composed of a pile number and a feature point data set, and the coordinates of the outermost feature points of the slope edges of each route are obtained from the feature point data set in the cross-sectional design line data array.

[0031] As a preferred solution, the steps also include, after generating the intersecting slope three-dimensional model, adding different colors and different materials to various parts of the roadbed model.

[0032] Based on the same concept, a roadbed three-dimensional BIM model slope intersection clipping system is also proposed, including at least one processor and a memory communicatively connected to the at least one processor; the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute any of the methods described above.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The intersection points obtained by the present invention are all accurate intersection points with negligible errors, and the slopes can be accurately cut. The road surface effect presented in the BIM modeling field is excellent. At the same time, in the field of highway design, the position where the cross-section line ends can be accurately calculated, which can effectively improve the original engineering approximation method. The entire process from the intersection area, slope intersection, setting shear points to drawing the model is an automated process, which can effectively solve the time-consuming and laborious problem of manual modification of slope intersection cutting problems in the field of highway design, and greatly improve efficiency. The present invention only takes 20% more time than the original modeling to accurately cut out the accurate slope effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of obtaining an approximate intersection point in the background technology of the present invention;

[0036] Figure 2 In the background technology of the present invention, the intersection point of two cross-section lines is used as an approximate intersection point, which causes the intersection and cutting of the generated roadbed three-dimensional modeling slope to deviate;

[0037] Figure 3 A flow chart of a method for cutting slope intersections in a three-dimensional BIM model of a roadbed in Embodiment 1 of the present invention;

[0038] Figure 4 This is a schematic diagram of the intersection of the closed area in Example 1 of the present invention;

[0039] Figure 5 This is an algorithm diagram of the line-to-line intersection method in the vertical viewing angle of the top view in Example 1 of the present invention;

[0040] Figure 6 This is an algorithm diagram of the line-to-line intersection method in a horizontal two-dimensional plane in Example 1 of the present invention;

[0041] Figure 7 It is a schematic diagram of drawing a spatial triangular surface in Embodiment 1 of the present invention. DETAILED DESCRIPTION

[0042] The present invention is further described in detail below in conjunction with test examples and specific implementation methods. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0043] Example 1

[0044] A method for cutting slope intersections in a three-dimensional BIM model of a roadbed, comprising the following steps:

[0045] S1 obtains the slope edges of two intersecting routes, and connects the coordinates of the outermost feature points of the slope edges of each route in a clockwise or counterclockwise order to form a closed curve;

[0046] S2 generates the intersection area of ​​the two intersecting routes according to the closed curve; and calculates the coordinates of the intersection point of the slope intersection using the line-line intersection algorithm within the intersection area;

[0047] S3 cuts the route cross-section design line based on the coordinates of the intersection points of the slopes, and generates a three-dimensional model of the intersecting slopes.

[0048] Figure 3 A flowchart of a specific implementation method for slope intersection clipping of a roadbed three-dimensional BIM model is given, including the following steps:

[0049] Step 1: Sample and obtain the route cross-section design line data array.

[0050] Step 2: Automatically obtain the intersection area of ​​two routes.

[0051] Step 3: Accurately calculate the slope intersection.

[0052] Step 4: Set the slope shear point and cut the cross section line.

[0053] Step 5: Draw the model.

[0054] Step 1 specifically includes:

[0055] (1) Sampling data according to rules. Generally, the route is sampled from small pile numbers to large pile numbers at a certain sampling interval, such as 10 meters. When encountering special places such as transition curves, circular transition curves, and the junction of bridges, tunnels and roadbeds, the sampling interval can be appropriately reduced to obtain a more refined model expression.

[0056] (2) At each pile number, the cross-section design line at that pile number is calculated using the latitude and longitude file parameters and high-precision terrain calculations.

[0057] A cross-section design line corresponds to a pile number, and a cross-section design line is composed of several feature points. The line segment between each two adjacent feature points represents a part of the roadbed, which belongs to one of the following roadbed types: median strip, earth shoulder, driving lane, shoulder wall, fill slope, embankment wall, ditch, cutting wall, cut slope, etc.

[0058] A feature point includes the three-dimensional coordinates of the point and the feature number. The feature number is unique in the same cross section and is used to indicate what type of roadbed the feature point can form with the adjacent feature points. The feature numbers are in order, which is consistent with the geometric arrangement of roadbed types. For example, from the center line of the road to both sides of the roadside (from the inside to the outside), they are: median strip, earth shoulder, driving lane, earth shoulder, shoulder wall, fill slope, embankment wall, ditch, cutting wall, excavation slope, etc. All route cross sections need to use the same order of feature numbering rules.

[0059] (3) Save the result of the previous step as a cross-section design line data array. The array consists of several cross-section design lines, and a cross-section design line consists of a pile number and a feature point data set. The array is sorted from small to large by pile number.

[0060] The goal of step 2 is to automatically calculate the intersection area of ​​the slopes of the two routes, and obtain the corresponding pile number intervals and left and right side information of the two routes.

[0061] The step 2 specifically includes:

[0062] (1) Calculate the slope edge of each route. Connect the coordinates of the outermost points on the left and right sides of each route in a clockwise or counterclockwise order to form a closed curve, which is the slope edge.

[0063] Taking clockwise as an example, the left point coordinates are connected from small pile numbers to large pile numbers to form the left curve point coordinate array, including [Point L1 ,Point L2 ,…,Point LN ], and then connect the right point coordinates from large stake to small stake to form the right curve point coordinate array, including [Point RN ,…,Point R2 ,Point R1 ].

[0064] The two arrays are connected into one array, which is the coordinate array of the closed slope edge line, representing the slope edge line of the route. L1 ,Point L2 ,…,Point LN ,Point RN ,…,Point R2 ,Point R1 ].

[0065] (2) Each route corresponds to a coordinate array of a closed slope sideline. When two routes intersect, the closed slope sidelines of the two routes also have an intersection. The intersection of the two closed slope sidelines is found using geometric algorithms and line intersection algorithms. The specific method for finding the intersection of the slope sidelines of two routes is as follows: if the three-dimensional coordinates of each point that constitutes the closed slope sideline in the two routes are known, the closed slope sideline can be outlined to obtain the intersection point and the pile number corresponding to the intersection point. It is necessary to pay attention to whether one of the routes crosses the other route to form a "closure". Crossing is defined as the coordinates of the two points in the array that are adjacent to the intersection point are located inside and outside the closure of the other curve, respectively. Intersection points that do not form a crossing need to be discarded, and the remaining intersection points are valid intersection points. Figure 4 As shown in the figure, the area between points AB is a valid intersection area, but BC is not. This is because point C does not cross the closure formed by the edge of the other slope and cannot form a valid intersection slope.

[0066] (3) Calculate the starting and ending pile numbers of the intersection area through the intersection point and obtain the coordinate array of the left and right slope edge lines of the intersection area, and record them. For the case of valid intersection points, sort the arrays of the two routes from small to large according to the pile number of the main route, and each group of two is an intersection area. Calculate the starting and ending pile numbers of the two routes through the starting and ending intersection points respectively, and judge whether the intersection position is on the left or right side of the center line according to the center line of the road. The closed area formed by the coordinate points corresponding to the left pile number of one route (such as the main route) and the coordinate points corresponding to the right pile number of the other route (such as the secondary route) with the starting and ending intersection points as the boundary is the intersection area. Each intersection area is composed of the starting and ending pile numbers of the main route, the roadside of the main route, the starting and ending pile numbers of the secondary route, and the roadside of the secondary route. Two routes can have multiple intersection areas.

[0067] The goal of step 3 is to accurately calculate the coordinates of the intersection point of the slopes in a certain intersection area of ​​the two routes through an algorithm. The algorithm is a line-line intersection method. Starting from the cross-section line of a certain pile number of one route, through the cross-section design line and the roadbed edge line of the other route, the accurate slope intersection point is calculated using a geometric line-line intersection algorithm. For example, the line-line intersection algorithm diagram under a vertical perspective is as follows: Figure 5 As shown, the algorithm diagram of the line-line intersection method in a horizontal two-dimensional plane is as follows: Figure 6 As shown, combined Figure 5 and Figure 6 , the specific steps of the line-line intersection algorithm are as follows:

[0068] The intersection area of ​​the two routes is extracted as input data. One is used as the main route and the other is used as the secondary route (for example Figure 5 The line where point A is located is the main line, and the line where point B is located is the secondary line). An intersection area is composed of the starting and ending pile numbers of the main line, the roadside of the main line, the starting and ending pile numbers of the secondary line, and the roadside of the secondary line.

[0069] The pile numbers in the intersection area of ​​the main route are arranged from small to large, starting from the starting pile number and ending at the end pile number, repeat the following steps:

[0070] (1) The current main route stake number is K main . From a vertical perspective (such as Figure 5 As shown in the figure, in the two-dimensional plane coordinate system, obtain the edge feature points on the side of the main route, take the edge feature as the starting point, and extend it in a direction perpendicular to the edge until the extension line intersects with the roadbed edge of the secondary route at point B. Based on point A, obtain the main route pile number corresponding to point A and the cross-section design line of a certain roadside corresponding to the line pile number (perpendicular to the center line of the main route). If the intersection point B of the roadbed edge of the secondary route does not exist, exit the current loop and enter (1) with the next pile number. Otherwise, enter step (2).

[0071] (2) The midpoint C of the intersection of the above two points A and B is taken as the starting point, and the horizontal offset of point C relative to point A on the cross section of the main route is recorded as x0.

[0072] (3) Draw a perpendicular line from the point with horizontal offset x0 (point C) to the roadbed edge line on the side of the secondary line and intersect it at point D. Corresponding to a stake number K on the secondary line sub . Get the cross-section design line of the secondary route at this stake number.

[0073] (4) The horizontal offset between point D and point C below the secondary route cross-section design line is denoted as y0.

[0074] (5) Change the main route to K main The roadside cross-section design line and the secondary route K under the pile number sub The roadside cross-section design lines under the pile number are placed on the same two-dimensional plane from a horizontal perspective (such as Figure 6 As shown in Figure 2 ), we can get ΔV and ΔH, where the elevation difference between point A and point D is ΔV and the horizontal difference ΔH = x0 + y0, and ΔV and ΔH are used for positioning.

[0075] (6) On this two-dimensional plane, the main route K main The roadside cross-section design line and the secondary route K under the pile number sub The roadside cross-section design line under the pile number intersects at point E. If point E does not exist, exit the current loop and enter (1) with the next pile number. If point E exists, the horizontal offset of point E relative to point A on the main route cross section is recorded as x1.

[0076] (7) Calculate the difference between the current horizontal offset and the previous horizontal offset Δ = x1-x0. If Δ is less than the specified threshold parameter x threshold (e.g. 0.001m), then point E is considered to be the exact intersection point, and the current loop is exited and the next pile number is entered into (1). Otherwise, the secondary route K is found again with the initial horizontal offset x1. sub The roadside cross-section design line under the pile number is repeated in steps (3) to (7) to calculate the new E, and then determine whether Δ is less than the specified threshold parameter x. threshold .

[0077] (8) If the number of cycles of steps (3) to (7) exceeds the specified threshold parameter t threshold (For example, 10 times), then exit the current loop and enter (1) with the next pile number.

[0078] The above iterative method is used to make the main route K main The roadside cross-section design line and the secondary route K under the pile number sub The intersection point E obtained by placing the roadside cross-section design line under the pile number on the same two-dimensional plane from a horizontal perspective is getting closer and closer to the accurate intersection point, making the final generated slope intersection cutting more accurate.

[0079] The step 5 specifically includes:

[0080] The trimmed cross-section design line is constructed into a three-dimensional surface using the same method as the model surface. Specifically, the points with the same feature number in the two cross-sections are connected into a line, and there are four feature points in the two lines of adjacent feature numbers. The four feature points have four three-dimensional point coordinates. If two spatial triangular faces that do not overlap and are completely contained in the vertices can be drawn, they are considered to be valid spatial triangular faces. The schematic diagram of drawing spatial triangular faces is as follows Figure 7 shown.

[0081] Since the line segment between every two adjacent feature points represents a part of the roadbed, this part belongs to a roadbed type, such as: median strip, earth shoulder, driving lane, shoulder wall, fill slope, embankment wall, ditch, cutting wall, excavation slope, etc. Different colors and materials can be assigned to different roadbed models to achieve a perfect model display effect. This process is the process of modeling and outputting the model.

[0082] The method proposed in this invention aims to solve the problem of slope intersection and cutting in the process of 3D BIM modeling of highway engineering roadbed. It has the following distinct advantages:

[0083] 1) Fully automatic

[0084] The entire process, from intersection areas, slope intersection, shear point setting to model drawing, is an automated process, which can effectively solve the time-consuming and labor-intensive problem of manual modification of slope intersection and cutting problems in the highway design field, greatly improving efficiency.

[0085] 2) High accuracy

[0086] The intersection points obtained by the present invention are all accurate intersection points with negligible errors, and the slopes can be accurately cut. The road surface effect presented in the BIM modeling field is excellent. At the same time, in the field of highway design, the original engineering approximation method can be effectively improved because the termination position of the cross-section line is accurately calculated.

[0087] 3) Fast speed

[0088] The present invention only needs to increase the time by 20% on the basis of the original modeling to accurately cut out the accurate slope effect. In addition, thanks to the reasonable loading and calculating strategy and the appropriate progress bar setting, the user's perception of the time change is not obvious.

[0089] The invention can automatically, accurately and efficiently calculate the slope intersection cutting point and automatically cut the cross section line. The invention can also be applied to accurate slope intersection cutting during roadbed design.

[0090] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for cutting slope intersections in a three-dimensional BIM model of a roadbed, characterized in that: The following steps are involved: S1 obtains the slope edges of two intersecting routes, and connects the coordinates of the outermost feature points of the slope edges of each route in a clockwise or counterclockwise order to form a closed curve; S2 generates the intersection area of ​​the two intersecting routes according to the closed curve; and calculates the coordinates of the intersection point of the slope intersection using the line-line intersection algorithm within the intersection area; S3: cutting the route cross-section design line based on the coordinates of the intersection points of the slopes, and generating a three-dimensional model of the intersecting slopes; The method of calculating the intersection coordinates of the slope intersections by using the line-line intersection algorithm includes: obtaining the characteristic points of the intersection area; arranging the characteristic points of the intersection area in ascending order of pile numbers, from the starting pile number to the end pile number, repeating the following steps: taking the cross-section line corresponding to the pile number of one of the routes as a reference, through the cross-section design line and the roadbed edge line of the other route, using the iterative calculation of the geometric line-line intersection, obtaining the intersection coordinates of the slopes of the two intersecting routes under the pile number; The step of obtaining the slope intersection coordinates of the two intersecting routes under the stake number specifically includes the following steps: S21 obtains the current main line stake number of the main line, and takes the roadbed edge line feature point A corresponding to the current main line stake number as the starting point in the two-dimensional plane coordinate system from a vertical perspective, and extends the auxiliary line in a direction perpendicular to the main line edge line until the auxiliary line intersects the roadbed edge line of the secondary line at point B; S22, on the line connecting point A and point B, with point A as the starting point, obtains point C with a horizontal offset x0, and obtains point C, draws a perpendicular line from point C to the roadbed edge line on the side of the secondary road, intersecting at point D, and obtains the secondary road pile number corresponding to point D; S23 projects the cross-section design line at the stake number of point A of the main route and the cross-section design line at the stake number of point D of the secondary route onto the same two-dimensional plane, and obtains the intersection point E of the cross-section design lines of the main route and the secondary route; S24 calculates the horizontal offset x1 of point E on the main route cross section based on point E, and calculates the difference in horizontal offset ,like Less than the specified threshold parameter , it is considered that point E is the final slope intersection point. Otherwise, replace x0 with x1 and re-execute steps S22 to S24 until Less than the specified threshold parameter .

2. A method for cutting slope intersections in a three-dimensional BIM model of a roadbed as claimed in claim 1, characterized in that: The generated intersection area of ​​the two intersecting routes satisfies the following conditions: For two intersecting closed curves, feature points adjacent to the intersection point on one of the closed curves are located outside and inside the closed region of the other closed curve, respectively.

3. A method for cutting slope intersections in a three-dimensional BIM model of a roadbed as claimed in claim 1, characterized in that: When point C is obtained for the first time, the horizontal offset x0 is half of the line from point A to point B.

4. A method for cutting slope intersections in a three-dimensional BIM model of a roadbed as claimed in claim 1, characterized in that: The generating of the intersecting slope 3D model comprises the following steps: The points with the same feature number in the two cross sections are connected into a line. There are four feature points in the two lines connecting adjacent feature numbers, and there are four feature point coordinates for the four feature points. If two non-overlapping spatial triangular faces can be drawn and the four points are completely contained in the vertices, they are considered to be valid spatial triangular faces, and a three-dimensional face is constructed. The three-dimensional face is the three-dimensional model of the intersecting slope.

5. A method for cutting slope intersections in a three-dimensional BIM model of a roadbed as claimed in claim 1, characterized in that: The types of roadbed include: median strip, earth shoulder, driving lane, earth shoulder, shoulder wall, fill slope, embankment wall, side ditch, cutting wall, and cut slope.

6. The method for cutting slope intersections in a three-dimensional BIM model of a roadbed according to claim 1, characterized in that: In step S1, after obtaining the slope edges of two intersecting routes, the cross-section design line data array of each route is obtained, and the array is composed of several cross-section design lines. A cross-section design line is composed of a pile number and a feature point data set. The coordinates of the outermost feature points of the slope edge of each route are obtained from the feature point data set in the cross-section design line data array.

7. The method for cutting slope intersections in a three-dimensional BIM model of a roadbed according to claim 1, characterized in that: The steps also include, after generating the intersecting slope three-dimensional model, adding different colors and different materials to various parts of the roadbed model.

8. A roadbed three-dimensional BIM model slope intersection cutting system, characterized in that: It includes at least one processor and a memory communicatively connected to the at least one processor; the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method described in any one of claims 1 to 7.

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