Linear engineering three-dimensional modeling method and system

Abstract

The invention relates to the field of building informatization models, and discloses a linear engineering three-dimensional modeling method and system, and the method comprises the steps: S1, reading plane data of a line center line, carrying out the differential processing of a curve segment into a plurality of straight line segments, and calculating the actual length of each line segment and a stake number corresponding to each point; s2, reading the longitudinal section data of the line center line, and when the mileage and the elevation of the longitudinal section adopt different proportions, carrying out conversion to obtain converted longitudinal section data; s3, calculating coordinates of elevation inflection points according to the converted longitudinal section data, inserting the elevation inflection points into the plane data, and then calculating the elevation of each vertex by using an interpolation method to obtain three-dimensional coordinates of each vertex; and S4, drawing a three-dimensional path corresponding to the line center line according to the three-dimensional coordinate of each vertex. According to the method, the three-dimensional center line can be quickly generated through the center line and the longitudinal section of the existing two-dimensional plane graph.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of building information modeling, and in particular to a linear engineering three-dimensional modeling method and system. BACKGROUND

[0002] Building information modeling (BIM) can provide intuitive three-dimensional models to help designers, owners and construction parties better understand the building form and spatial relationship, multi-specialty collaboration and improve design efficiency. The length of the line of railway, highway and other linear engineering often exceeds ten thousand meters. In the prior art, when the two-dimensional line is inversely projected into three dimensions, the spatial curve is difficult to express in a simple analytical form. A new method is needed to quickly convert from two dimensions to three dimensions. SUMMARY

[0003] The present application provides a linear engineering three-dimensional modeling method. The purpose of the present application is to identify the plane of the line center line, the data of the longitudinal section, and inversely project the two groups of two-dimensional lines into three-dimensional lines. A linear engineering three-dimensional modeling method comprises the following steps: Step S1: read the plane data of the line center line, differentiate the curve segment into multiple straight line segments, calculate the actual length of each line segment and the stake number corresponding to each point; Step S2: read the longitudinal section data of the line center line. When the mileage and elevation of the longitudinal section use different scales, conversion is needed to obtain the converted longitudinal section data; Step S3: calculate the elevation inflection point coordinates according to the converted longitudinal section data, and insert the elevation inflection point into the plane data, then calculate the elevation of each vertex using interpolation method to obtain the three-dimensional coordinates of each vertex; Step S4: draw the three-dimensional path corresponding to the line center line according to the three-dimensional coordinates of each vertex.

[0004] The second aspect of the present application provides a linear engineering three-dimensional modeling system, comprising: a plane data reading module: reading the plane data of the line center line, differentiating the curve segment into multiple straight line segments, calculating the actual length of each line segment and the stake number corresponding to each point; a longitudinal section data reading module: reading the longitudinal section data of the line center line. When the mileage and elevation of the longitudinal section use different scales, conversion is needed to obtain the converted longitudinal section data; a three-dimensional coordinate calculation module: calculating the elevation inflection point coordinates according to the converted longitudinal section data, and inserting the elevation inflection point into the plane data, then calculating the elevation of each vertex using interpolation method to obtain the three-dimensional coordinates of each vertex; a drawing module: drawing the three-dimensional path corresponding to the line center line according to the three-dimensional coordinates of each vertex.

[0005] The present application has the following beneficial effects: 1. The present application provides a linear engineering three-dimensional modeling method, which can quickly generate a three-dimensional center line through the existing two-dimensional planar center line and longitudinal section.

[0006] 2. Realize three-dimensional horizontal offset of multi-segment line. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1 is a flowchart of a linear engineering three-dimensional modeling method; Figure 2 is the expression form of a circular arc under the form of a multi-segment line; Figure 3 is a schematic diagram of bisection circle; Figure 4 is the influence of the offset algorithm considering superelevation on the transition curve and circular curve segment. DETAILED DESCRIPTION

[0008] The terms "first", "second", "third", "fourth" and the like in the description and claims of the present application and in the above drawings (if any) are used for distinguishing between similar objects, not necessarily for describing a particular sequential or chronological order. It is to be understood that the use of such terms, if any, are not to be construed as placing limitations on the scope of the embodiments described herein. It is to be understood that the data shown herein is presented by way of example only and that the embodiments described herein can operate within a range of values that is different from those expressly disclosed. Furthermore, the term "comprising" or "containing" and variations thereof as used herein is used generically and inclusively, in connection with explaining processes, methods, systems, products or equipment that contain, or include, a list of steps or elements but it is not used in connection with excluding any steps or elements apart from those explicitly identified, or inherent to such processes, methods, products or equipment.

[0009] The route of linear engineering is composed of route plane and route longitudinal section.

[0010] Among all the elements of route plane, the most important one is route center line. The route center line of linear engineering such as highway and railway is generally composed of straight line, circular curve and transition curve. In common design cases, transition curve is fitted by multiple short straight lines or circular arcs. Therefore, the route center line can be combined into a multi-segment line composed of straight line and circular arc.

[0011] Route longitudinal section adopts two kinds of line shapes, straight line and vertical curve, which are the basic elements of longitudinal section line shape. Vertical curve often adopts parabola because it is more convenient than circular curve in design and calculation. Therefore, the longitudinal section line can be combined into a multi-segment line composed of straight line segments.

[0012] In AutoCAD and other CAD software, there are two types of multi-segment line, namely traditional multi-segment line (POLYLINE) and lightweight multi-segment line (LWPOLYLINE).

[0013] The POLYLINE data structure is complex. It supports 3D vertices (each vertex can have an independent Z coordinate) and can contain complex elements (such as arc segments and nested polylines). It is typically used in older versions or scenarios that require 3D features.

[0014] LWPOLYLINE was introduced in AutoCAD R14 and is the default polyline type in subsequent versions. It features a more optimized storage structure and is characterized by: 1) lightweight; 2) 2D only (with a uniform Z coordinate); and 3) a single entity.

[0015] Therefore, in plan view, after a polyline is joined using the Join command, its form is generally LWPOLYLINE. The group codes with geometric meaning include: Group code 90: Number of vertices; Group code 70: Polyline flag (bit-coded), default value is 0, 1 = closed, 128 = polyline generated; Group code 10: X value of vertex coordinate (in OCS), multiple entries; one entry for each vertex; Group code 20: Y value of vertex coordinate (in OCS), multiple entries; one entry for each vertex; Group code 42: Bulge (multiple entries; one entry for each vertex) (optional; default value = 0).

[0016] The advantage of LWPOLYLINE is that it introduces the concept of bulge, which allows lines and arcs to be expressed in the same form. Bulge is a very important concept in AutoCAD. It controls the size and direction of the arc between two points. ) is defined as the angle contained by the arc ( )1 / 4, that is: .

[0017] When the chord length of the arc is known ( ) and convexity ( ), the arc length ( ) and radius ( ): When a two-dimensional line is reverse-projected into three dimensions, it is difficult to express the spatial curve using a concise analytical form. Therefore, the present invention simplifies the plane arc segment into a straight line segment, and then reverse-projects it into a three-dimensional polyline composed of straight lines.

[0018] For ease of understanding, the specific process of the embodiment of the present invention is described below. Figure 1-4 The first embodiment of the linear engineering 3D modeling method in the embodiment of the present invention includes: Step S1: Read the plane data of the line centerline, differentiate the curve segment into multiple straight line segments, and calculate the actual length of each line segment and the stake number corresponding to each point; Step S2: Reading the longitudinal section data of the line centerline. When the mileage and elevation of the longitudinal section adopt different ratios, conversion is required to obtain the converted longitudinal section data. Step S3: Calculate the coordinates of the elevation inflection point based on the converted longitudinal section data, insert the elevation inflection point into the plane data, and then calculate the elevation of each vertex using the interpolation method to obtain the three-dimensional coordinates of each vertex; Step S4: Draw a three-dimensional path corresponding to the line centerline based on the three-dimensional coordinates of each vertex.

[0019] In a preferred embodiment of the present invention, step S1 reads the plane data of the center line of the line, uses the straight line segment to differentiate the curve, and calculates the actual length of each line segment and the stake number corresponding to each point.

[0020] The route centerline plane data includes route centerline data (LWPOLYLINE format) and stake number data (starting point, hundred-meter mark, broken link insertion coordinates and their corresponding text).

[0021] Linear Engineering Planes Figure 1 Generally, the city plane coordinate system is used (i.e., X and Y coordinates are used instead of longitude and latitude). The graphic unit is meter, so it can be called directly. The two-dimensional polyline corresponding to the center line of the line can be expressed as an open polyline with N vertices, and its vertices are recorded as .

[0022] When the generated centerline is a closed polyline, it should be adjusted to an open polyline in CAD.

[0023] When the order of the polyline vertices is opposite to the direction of mileage increase, you can use the Pedit command to reverse the direction. You can also reverse the direction of the line using the following formula: when Sometimes, there are , , .

[0024] when hour, It is a straight line and can be used directly.

[0025] when hour, It is an arc. When the arc is straightened into a straight line, it will cause length error. and lateral error .

[0026] use and When the error is expressed, , .

[0027] use and When the error is expressed, , .

[0028] The length and lateral errors can be reduced by dividing the arc into smaller arcs.

[0029] After the length error and lateral error meet the setting requirements, the default 0, that is, only the chord length is calculated .

[0030] The mileage corresponding to each vertex of the center line can be calculated by the method of "starting pile number + cumulative length". The new data set is recorded as ,in, .

[0031] According to a preferred embodiment of the present invention, step S2 reads and converts the longitudinal section data of the line centerline.

[0032] In order to ensure that the scale of the longitudinal section is appropriate, the mileage and elevation of the longitudinal section are often in different scales. Therefore, the longitudinal section data needs to be converted before use. and elevation It can be calculated by the following formula: , Where, 、 、 and They are all constant coefficients and can be calculated using the slope-intercept form.

[0033] In a preferred embodiment of the present invention, step S3 is as follows: calculating the coordinates of the elevation inflection points and inserting them, and calculating the elevation of each vertex using an interpolation method.

[0034] According to the pile number corresponding to the elevation inflection point , insert the inflection point and elevation in the polyline, calculate its coordinates, and then use interpolation to calculate the elevation of each remaining vertex At this time, the data set is recorded as .

[0035] Through the offset algorithm, the horizontal offset and vertical displacement of the three-dimensional polyline can be achieved, and other paths can be quickly drawn.

[0036] In a preferred embodiment of the present invention, step S4: drawing a three-dimensional polyline: using the 3DPOLY command based on the three-dimensional coordinates of each vertex, a three-dimensional path corresponding to the line centerline is drawn.

[0037] Some specific steps of the present invention are described in detail below: Divide the arc equally Divide the arc into two equal parts, and there are two paths.

[0038] One is the dichotomy method. For a certain arc segment, in the form of a two-dimensional polyline, the starting and ending points and the convexity can be recorded as 、 and The coordinates of the midpoint of the arc are written as , the convexity of the two arcs after equal division is recorded as At this time, there is use and Represents the error, iterate until the length error limit is met and lateral error limits .

[0039] The second method is to divide the arc into n equal parts. In this case, the radius of the arc needs to be calculated. and arc length .use and Indicates the length error and lateral error, and determines how many equal segments the arc needs to be divided into.

[0040] Calculating the center coordinates and the central angle Then, the coordinates of each equally divided point can be obtained .

[0041] in: Calculate the stake number corresponding to each vertex Generally speaking, the mileage corresponding to each vertex of the center line can be calculated by the method of "starting point pile number + cumulative length".

[0042] However, in actual projects, due to local line changes or segmented measurements, pile numbers may become disconnected, i.e., a chain break. In this case, subsequent pile numbers should be recalculated based on the mileage after the chain break. For example, if AK1+195=AK1+200 (the chain is 5 meters short), AK1+200 should be used as the corresponding pile number.

[0043] At this time, it is necessary to insert a broken link point in the existing multi-segment line, and the calculation of the stake numbers of subsequent vertices starts from this point.

[0044] To prevent the accumulation of length errors, you can avoid it by inserting hundred-meter markers (coordinates and stake numbers) into the polyline.

[0045] The insertion point is denoted as , the insertion point must be located on the center line of the line, so it is only necessary to determine between which two vertices the insertion point is located. At this point, the two-dimensional polyline with arcs has been simplified to a polyline composed of pure straight lines. Therefore, when the following formula is satisfied, it can be determined that lie in between.

[0046] Inserting an elevation inflection point on a 2D polyline In addition to the pile number and elevation of the elevation inflection point, the pile number and elevation corresponding to the chain break point should also be exported synchronously. When the chain break is a long chain, the pile numbers of some sections will be repeated, making it impossible to accurately insert the elevation. In this case, the line can be processed in sections.

[0047] The derived elevation inflection point is recorded as , at this time, you need to calculate the corresponding coordinates according to the stake number. According to the stake number, you can quickly find which two points T is between ( ). At this time, the coordinates of the inflection point are: Elevations of remaining vertices It can be easily found by interpolation.

[0048] The positional relationship between the remaining lines in the line plan, such as tracks and road red lines, and the center line is horizontal offset and vertical translation, specifically including: Centerline offset When the three-dimensional coordinates of each vertex of the line centerline are known, the new coordinates after the horizontal offset distance d (when d is greater than 0, it is offset to the left; otherwise, it is offset to the right) can be recorded as : Among them, when hour, ; ;when hour, ; .

[0049] Offset algorithm for circular curves taking superelevation into account Curve superelevation is a professional term in the field of railway science and technology, which refers to the height increase set on the outer rails of a curved track. , used to balance the centrifugal force generated when the train passes through the curve. is a fixed value. At this time, the three-dimensional coordinates of the rails on both sides of the center line can be recorded as: in, To indicate the sign of the parameter x, it returns 1 when x>0, -1 when x<0, and 0 when x=0.

[0050] Offset algorithm for transition curves taking superelevation into account The offset of the spiral curve segment with superelevation is similar to that of the circular curve segment. It is only necessary to calculate the actual superelevation of each point on the spiral curve.

[0051] According to the definition of superelevation and transition curve, the superelevation of each point on the transition curve Corrected to or .in, is the length of the transition curve, is the cumulative length of the transition curve corresponding to this point.

[0052] The above describes the linear engineering 3D modeling method according to the embodiment of the present invention. The following describes the linear engineering 3D modeling device according to the embodiment of the present invention. Plane data reading module: reads the plane data of the line centerline, differentiates the curve segment into multiple straight line segments, and calculates the actual length of each line segment and the stake number corresponding to each point; Longitudinal section data reading module: reads the longitudinal section data of the line centerline. When the mileage and elevation of the longitudinal section use different ratios, conversion is required to obtain the converted longitudinal section data; 3D coordinate calculation module: Calculate the coordinates of the elevation inflection point based on the converted longitudinal section data, insert the elevation inflection point into the plane data, and then use the interpolation method to calculate the elevation of each vertex to obtain the 3D coordinates of each vertex; Drawing module: Draw the three-dimensional path corresponding to the center line of the line based on the three-dimensional coordinates of each vertex.

[0053] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A linear engineering three-dimensional modeling method, characterized in that: The method comprises the following steps: Step S1: Read the plane data of the line centerline, differentiate the curve segment into multiple straight line segments, and calculate the actual length of each line segment and the stake number corresponding to each point; Step S2: Reading the longitudinal section data of the line centerline. When the mileage and elevation of the longitudinal section adopt different ratios, conversion is required to obtain the converted longitudinal section data. Step S3: Calculate the coordinates of the elevation inflection point based on the converted longitudinal section data, insert the elevation inflection point into the plane data, and then calculate the elevation of each vertex using the interpolation method to obtain the three-dimensional coordinates of each vertex; Step S4: Draw a three-dimensional path corresponding to the line centerline based on the three-dimensional coordinates of each vertex.

2. A linear engineering three-dimensional modeling method according to claim 1, characterized in that: The specific steps of step S1 are: The line centerline plane data includes line centerline data and stake number data, and the stake number data includes a starting point, a hundred-meter mark, a broken link insertion coordinate and corresponding text; The two-dimensional polyline corresponding to the center line of the line can be represented as an open polyline with N vertices, whose vertices are recorded as ; in, ——the i-th vertex on the polyline, ——X-axis coordinate, ——Y-axis coordinate, — convexity; When the generated centerline is a closed polyline, it should be adjusted to an open polyline in CAD; When the order of the polyline vertices is opposite to the direction of increasing mileage, the direction of the line is reversed using the following formula: when Sometimes, there are , , ; in, 、 、 are the new coordinates and convexity after adjustment; when hour, It is a straight line and can be used directly; when hour, It is an arc. When the arc is straightened into a straight line, it will cause length error. and lateral error ; Use chord length and convexity When the error is expressed, , ; Use Arc Length and radius When the error is expressed, , ; By dividing the arc into smaller arcs, the length and lateral errors are reduced; After the length error and lateral error meet the setting requirements, the default 0, that is, only the chord length is calculated ; The mileage corresponding to each vertex of the center line can be calculated by the method of "starting point number + cumulative length". The new data set is recorded as ,in, The stake number corresponding to the i-th vertex on the polyline: .

3. A linear engineering three-dimensional modeling method according to claim 2, characterized in that: The specific method of dividing the arc into equal parts is: For a certain arc segment, in the form of a two-dimensional polyline, the starting and ending points and the convexity can be expressed as 、 and ; Mark the coordinates of the arc's midpoint , the convexity of the two equally divided arcs is recorded as At this time, there is Use chord length and convexity Represents the error, iterate until the length error limit is met and lateral error limits .

4. A linear engineering three-dimensional modeling method according to claim 2, characterized in that: The specific method of dividing the arc into equal parts is: Directly divide the arc into n equal parts and calculate the radius of the arc and arc length ;use and Indicates length error and lateral error, and determines how many equal segments the arc needs to be divided into; Calculating the center coordinates and the central angle Then, the coordinates of each equally divided point can be obtained ; in: 。 5. A linear engineering three-dimensional modeling method according to claim 1, characterized in that: The step S2 is specifically as follows: When the mileage and elevation of the longitudinal section are often in different proportions, the longitudinal section data is converted before use: the pile number corresponding to the elevation inflection point and elevation Calculated by the following formula: Where, 、 、 and are all constant coefficients and are calculated using the slope-intercept form.

6. A linear engineering three-dimensional modeling method according to claim 1, characterized in that: Inserting the elevation inflection point into the plane data in step S3 includes: When the pile numbers of some sections are repeated, making it impossible to accurately insert the elevation, the line is divided into sections: The elevation inflection point is recorded as , calculate the coordinates corresponding to the elevation inflection point according to the stake number, and find between which two points the elevation inflection point T is located according to the stake number: , the two-dimensional coordinates of the elevation inflection point for: Elevations of remaining vertices It can be calculated by interpolation.

7. A linear engineering three-dimensional modeling method according to claim 1, characterized in that: The method further comprises the step of calculating the line centerline offset: When the three-dimensional coordinates of each vertex of the line centerline are known, the new coordinates after the horizontal offset distance d can be recorded as , the calculation formula is: Among them, when hour, ; ; when hour, ; ; When d is greater than 0, it is shifted to the left; otherwise, it is shifted to the right.

8. A linear engineering three-dimensional modeling method according to claim 1, characterized in that: The method further comprises the step of calculating the offset of the circular curve taking superelevation into account: The three-dimensional coordinates of the rails on both sides of the center line can be expressed as: in, To indicate the sign of the parameter x, when x>0, it returns 1, when x<0, it returns -1, and when x=0, it returns 0; is the track gauge, The height increase value set for the outer rails on curved tracks.

9. A linear engineering three-dimensional modeling system, characterized in that: The system comprises: Plane data reading module: reads the plane data of the line centerline, differentiates the curve segment into multiple straight line segments, and calculates the actual length of each line segment and the stake number corresponding to each point; Longitudinal section data reading module: reads the longitudinal section data of the line centerline. When the mileage and elevation of the longitudinal section use different ratios, conversion is required to obtain the converted longitudinal section data; 3D coordinate calculation module: Calculate the coordinates of the elevation inflection point based on the converted longitudinal section data, insert the elevation inflection point into the plane data, and then use the interpolation method to calculate the elevation of each vertex to obtain the 3D coordinates of each vertex; Drawing module: Draw the three-dimensional path corresponding to the center line of the line based on the three-dimensional coordinates of each vertex.

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