Method and system for creating a three-dimensional model of a draft tube

Abstract

The present application mainly relates to the field of three-dimensional modeling of hydroelectric engineering structure. In order to improve the accuracy and automation degree of the tail water channel three-dimensional model creation, the present application provides a tail water channel three-dimensional model creation method and system, the core idea of which is: collecting tail water channel parameters, converting them into spatial position parameters and contour shape geometric parameters; converting the contour shape geometric parameters into the established contour center coordinate system, and judging the contour type according to the contour shape geometric parameters; generating multiple coupling points on different feature positions based on the contour type; generating the NURBS curve of each contour according to the contour shape geometric parameters in the contour center coordinate system; selecting the coupling strategy, connecting the coupling points on different contours by the NURBS curve to generate the ridge line, and establishing the ridge line set; generating the tail water channel surface NURBS surface based on the NURBS curve of the contour and the generated ridge line, and then splicing to generate the tail water channel three-dimensional model.

Description

TECHNICAL FIELD

[0001] The present application mainly relates to the field of three-dimensional modeling of hydroelectric engineering structures, and particularly relates to a tailrace three-dimensional model creation method and system. BACKGROUND

[0002] The design of hydraulic structures plays a crucial role in modern hydroelectric engineering, and the accurate construction of tailrace is key to ensuring the safety and functionality of the structure. Tailrace itself often has extremely complex curved surfaces to meet complex hydraulic conditions. In modern hydraulic design, three-dimensional modeling is usually used to accurately express the geometric shape, which involves three-dimensional modeling of tailrace. Traditional modeling methods usually require manual setting of multiple cross-sectional profiles according to manufacturer parameters, and then constructing complex geometric shapes through stretching and sampling. However, this method is not only complex and inefficient, but also prone to errors due to human factors, resulting in rework and failing to meet the needs of rapid iterative design.

[0003] Currently, some automatic tailrace modeling methods have been proposed, but these methods often face many challenges. For example, grid-based modeling is used for tailrace modeling, but this method is difficult to effectively handle complex curved flow channel shapes, has poor compatibility with mainstream design software, and lacks parameterization, making it impossible to modify the model after it is established. Some tailrace modeling methods achieve automation to some extent, but still require manual intervention and adjustment, and cannot achieve fully automated modeling. SUMMARY

[0004] Technical problems to be solved by the present application

[0005] The present application provides a tailrace three-dimensional model creation method and system, aiming to improve the accuracy and automation of tailrace three-dimensional model creation.

[0006] Technical solutions adopted by the present application to solve the above technical problems

[0007] In one aspect, the present application provides a tailrace three-dimensional model creation method, comprising:

[0008] The tailrace three-dimensional model creation method comprises:

[0009] Step S1: Collect tailrace parameters and convert the collected tailrace parameters into profile data sets, wherein the profile data includes spatial position parameters and profile geometry parameters.

[0010] Step S2: converting the profile contour geometry parameters to the established profile center coordinate system according to the spatial position parameters of the profile;

[0011] Step S3: judging the profile type of each profile according to the profile contour geometry parameters in the profile center coordinate system;

[0012] Step S4: generating a plurality of coupling points on different feature positions based on the profile type;

[0013] Step S5: generating the NURBS curve set of each profile according to the profile contour geometry parameters in the profile center coordinate system;

[0014] Step S6: selecting a coupling strategy, connecting the coupling points on different profiles by NURBS curves to generate a spine line;

[0015] Step S7: generating the NURBS surface of the draft flow passage based on the NURBS curves of the profile and the generated spine line, splicing the generated NURBS surface to generate a three-dimensional model of the draft flow passage.

[0016] Further, the spatial position parameters of the profile in step S1 include the coordinates (x, y, z) of the profile in the world coordinate system, and the profile contour geometry parameters include the rotation angles θ, β, γ of the plane where the profile is located around the x, y, z axes, the width W of the profile, the height H of the profile, the upper half corner radius R1 of the profile, and the lower half corner radius R2 of the profile.

[0017] Further, the profile type in step S3 includes a circle, a single-side semicircle rectangle, a double-side semicircle rectangle, a single-side semicircle corner rectangle, a double-side semicircle corner rectangle, a single-side round corner rectangle, and a double-side round corner rectangle.

[0018] Further, step S4 includes: selecting a coupling point from the feature points of the profile according to the type of the current profile and the subsequent profile; and the feature points include the start point and the end point of the arc line, and the corner point of the rectangle.

[0019] Further, step S6 includes:

[0020] (1) generating a profile type list CT according to the profile type judgment result in step S3, and recording the number CT1, CT2, …, CT of each profile in the profile type list; n ;

[0021] (2) merging adjacent same profiles in the profile type list, and recording the number range [i, j] of each profile in each merged profile;

[0022] (3) merging adjacent same profiles in the profile type list CT to form the final profile type group CTC((T k,…) ; T k is the fused contour type;

[0023] (4) connecting the coupling points of all contours in the corresponding contour number range [i, j] in the contour type group CTC((T k , …), respectively according to the selected coupling strategy to form a ridge line set L(L1, L2, …, L k ).

[0024] Further, step S7 comprises:

[0025] (1) obtaining a contour NURBS curve set CS(CS1, CS2, …, CS n ), a ridge line set L(L1, L2, …, L k ), and a merged contour type group CTC((T k , …);

[0026] (2) according to the corresponding contour number range [i, j] in the contour type group CTC((T k , …), forming a tailrace NURBS surface model NS(NS1, NS2, …, NS n ) by calling the NURBS curve in the contour NURBS curve set CS(CS1, CS2, …, CS k ) and the ridge line in the ridge line set L(L1, L2, …, L k ) through a NURBS surface lofting algorithm;

[0027] (3) performing surface splicing on the NURBS surface model to generate a tailrace three-dimensional model.

[0028] Further, the generated tailrace three-dimensional model is exported in STP format.

[0029] On the other hand, based on the above tailrace three-dimensional model creation method, the application further provides a tailrace three-dimensional model creation system, comprising a data conversion module, a data preprocessing module, a cross section contour identification module, a coupling point generation module, a cross section contour generation module, a model lofting generation module, and a model export module;

[0030] The data conversion module is used to collect tailrace parameters and convert the collected tailrace parameters into contour data set parameters; the contour data set comprises spatial position parameters and contour shape geometry parameters of the contour;

[0031] The data preprocessing module is used to convert the contour shape geometry parameters to the established contour center coordinate system according to the spatial position parameters of the contour in the contour data set;

[0032] The section profile identification module is configured to determine the type of each profile according to the profile contour geometric parameters in the profile center coordinate system.

[0033] The coupling point generation module is configured to generate a plurality of coupling points at different feature positions based on the profile type.

[0034] The section generation module is configured to generate a NURBS curve for each profile according to the profile contour geometric parameters in the profile center coordinate system, and establish a NURBS curve set.

[0035] The model lofting generation module is configured to connect the corresponding coupling points on different section profiles using NURBS curves to generate a ridge line set according to the selected coupling strategy, generate a tailrace flow channel surface NURBS surface based on the NURBS curves of the profiles and the generated ridge lines, splice the generated NURBS surface, and generate a tailrace flow channel three-dimensional model.

[0036] The model export module is configured to export the generated tailrace flow channel three-dimensional model in a set export format.

[0037] Advantages of the present application

[0038] The tailrace flow channel three-dimensional model creation method and system disclosed by the present application converts tailrace flow channel original data into spatial position parameters and profile contour geometric parameters, develops and writes programs to preprocess the data, identifies each section profile data to determine the profile type, develops and writes programs to realize the drawing of each section profile of the tailrace flow channel, adds coupling points for the combination of different types of section forms, realizes multi-section lofting, and obtains the final flow channel model. The present application can realize the automatic generation of complex curved surface tailrace flow channels, greatly improves the modeling efficiency under the premise of ensuring high precision, reduces manual intervention, and meets the efficient and accurate requirements of modern hydraulic structure design for tailrace flow channel modeling. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 A tailrace flow channel three-dimensional model creation flowchart is provided.

[0040] Figure 2 A NURBS curve generated in an embodiment is provided.

[0041] Figure 3 A tailrace flow channel three-dimensional model generated in an embodiment is provided. DETAILED DESCRIPTION

[0042] The tailrace flow channel three-dimensional model creation system disclosed by the present application includes a data conversion module, a data preprocessing module, a section profile identification module, a coupling point generation module, a section profile generation module, a model lofting generation module, and a model export module. The tailrace flow channel three-dimensional model creation method disclosed by the present application is as follows:Figure 1 As shown.

[0043] The data conversion module converts the original manufacturer's tailrace flow parameters into a universal profile dataset parameter CP. The universal profile dataset parameter CP consists of multiple profile data (CP1, CP2, CP3, ..., CP...). n Composed of ) each contour data CP i It consists of the spatial position parameters and the geometric parameters of the contour. The spatial position parameters include the position coordinates of the contour in the world coordinate system (x, y, z). The geometric parameters of the contour include the rotation angles θ, β, γ of the plane containing the contour about the x, y, z axes, the width W of the contour, the height H of the contour, the chamfer radius R1 of the upper half of the contour, and the chamfer radius R2 of the lower half of the contour.

[0044] The data preprocessing module will use the parametric coordinate system S defined by the dataset CP. w Transform to the established contour center coordinate system S c (Cartesian coordinate system), where rotational transformations in coordinate system transformations are calculated using quaternions. For any contour, its rotation around any axis... Rotational quaternion q w for: Where α is the rotation angle of the profile about the axis, and the rotation quaternions q about the axes x, y, and z are calculated based on the rotation angles of the profile about the axes x, y, and z, respectively. x ,q y ,q z According to the rotation formula: in The normal vector of the contour plane. The z-axis vector is (0,0,1), and the flow direction vector is determined by the contour plane normal vector and the input flow direction vector. The third axis of the Cartesian coordinate system is obtained through the cross product of vectors. This forms a coordinate system with the plane containing the contour as the reference plane.

[0045] The cross-sectional contour recognition module is used to determine the contour type based on the contour shape geometric parameters in the contour center coordinate system.

[0046] The coupling point generation module is used to generate coupling points (S1, S2, ..., S) at different feature locations based on the contour type. j The coupling point is a feature point on the contour, which specifically includes the start / end point of the arc segment and the corner point of the rectangle.

[0047] The cross-section generation module generates NURBS curves for each contour based on the contour shape geometric parameters in the contour center coordinate system, and establishes a NURBS curve set CS(CS1,CS2,…,CS). n ).

[0048] The model lofting generation module stores coupling point coupling strategies between different types of contours, which are used to select a coupling strategy according to the contour type, and the coupling strategy is determined according to the geometric mapping relationship between the coupling points of the current contour and the subsequent contour. The corresponding coupling points on different cross-sectional contours are connected by NURBS curves to generate a ridge line set, and a tail water flow channel surface NURBS surface is generated based on the NURBS curves of the contours and the generated ridge line. The generated NURBS surface is spliced to generate a tail water flow channel three-dimensional model.

[0049] The model export module is used to export the generated tail water flow channel three-dimensional model in a set export format.

[0050] Further, the implementation method of generating a ridge line from a coupling point is as follows:

[0051] (1) Generating a contour type list according to the contour type identification result of the cross-sectional contour identification module, and recording the number CT (CT1, CT2, …, CT n ) of each contour;

[0052] (2) Merging adjacent same contours in the contour type list, and recording the number range of the merged contours;

[0053] (3) Merging adjacent same contours in the merged contours to form a final contour type group CTC ((T k , [i, j]), …); T k is the fused contour type;

[0054] (4) Connecting the coupling points of all contours in the corresponding contour number range [i, j] in the contour type group CTC ((T k , [i, j]), …) according to the selected coupling strategy to form a ridge line set L (L1, L2, …, L k ).

[0055] Further, the implementation method of generating a tail water flow channel surface NURBS surface is as follows:

[0056] (1) Obtaining a contour NURBS curve set CS (CS1, CS2, …, CS n ), a ridge line set L (L1, L2, …, L k ), and a merged contour type group CTC ((T k , [i, j]), …);

[0057] (2) According to the contour type group CTC ((T k,…) corresponding to the profile number range [i, j] in the profile data set CP, the NURBS curve in the profile NURBS curve set CS (CS1, CS2, …, CS n ) and the ridge line segment in the ridge line set L (L1, L2, …, L k ) are formed into the NURBS surface model NS (NS1, NS2, …, NS k ) of the tail water flow channel by calling the NURBS surface lofting algorithm.

[0058] (3) The surface splicing is performed on the NURBS surface model to generate the three-dimensional model of the tail water flow channel.

[0059] Embodiment

[0060] This embodiment further explains the modeling method and system for automatically creating the three-dimensional model of the tail water flow channel according to the modeling process of the tail water flow channel of a certain power station.

[0061] Step one, the tail water flow channel single-line diagram parameter table provided by the manufacturer, the data conversion module converts the original data in the parameter table into the profile data set CP in the format of (θ, β, γ, x, y, z, W, H, R1, R2), which includes the spatial position parameters and the profile geometric parameters of the profile, including the coordinates (x, y, z) of the profile in the world coordinate system, the profile geometric parameters including the rotation angles θ, β, γ of the profile around the x, y, z axes, the width W of the profile, the height H of the profile, the upper half chamfer radius R1 of the profile, and the lower half chamfer radius R2 of the profile.

[0062] Taking the profile CP3 in the profile data set of the tail water flow channel of a certain power station as an example, the parameters in the profile data set are (0, 3.041, 0, 45.9, 0, -9750.4, 6580.4, 6420.4, 3210.2, 3210.2), wherein the angles are in radians, and the rest of the dimensions are in millimeters;

[0063] Step two, the data preprocessing module converts the profile geometric parameters defined by the profile data set CP from the parameter coordinate system S w to the Cartesian coordinate system S c , and the rotation transformation in the coordinate system transformation is calculated by using the quaternion, and for any profile, the rotation quaternion q around any axis w is: wherein α is the rotation angle around the axis, and the rotation quaternions q x , q y , q z , and q x around the axes x, y, and z are calculated according to the rotation angles of the profile around the axes x, y, and z, respectively, and according to the rotation formula: where is the normal vector of the profile plane, is the z-axis vector (0,0,1), according to the profile plane normal vector and the input flow direction vector The third axis of the Cartesian coordinate system is obtained by vector cross product The coordinate axis system is constituted with the plane where the profile is located as the reference plane. Taking the profile CP3 as an example, its normal vector is calculated as The user input vector is

[0064] Step three, the profile contour recognition module recognizes the geometric features of the profile according to the profile contour geometric parameters (W, H, R1, R2), and divides the profile into eight different types (T1, T2, T3, T4, T5, T6, T7, T8), including a circle, a single-side semicircle rectangle, a double-side semicircle rectangle, a single-side semicircle corner rectangle, a double-side semicircle corner rectangle, a single-side round corner rectangle and a double-side round corner rectangle, wherein the round corner rectangle is subdivided into five types according to different chamfer positions and radii. In this embodiment, the CP3 profile is a circular profile.

[0065] Step four, the coupling point generation module generates coupling points (S1, S2, …, S i ) for each profile CP j The coupling points are feature points on the profile, including the start / terminal points of the arc segments and the corner points of the rectangle. According to the types of the current and subsequent profiles, a specific point set is selected from the feature points as the coupling points of the current profile. In this embodiment, the CP3 profile is divided into four coupling points by 1 / 4 circle.

[0066] Step five, the profile generation module generates NURBS two-dimensional curves (NS1, NS2, NS3, …, NS i ) of the profile according to the profile data CP n (i∈[1,n]) of the profile. The plane where the NURBS two-dimensional curves are located is the reference plane of the coordinate system calculated in step two. In this embodiment, the generated NURBS two-dimensional curves of the profile are shown in Figure 2 .

[0067] Step six: according to the geometric mapping relationship of the profile coupling points in the selected coupling strategy, the coupling points on different profiles are connected by NURBS curves to generate a spine line, and a spine line set L (L1, L2, …, L k ) is established.

[0068] Step seven, according to the generated profile NURBS curves, a general lofting algorithm in three-dimensional design is used to construct a tailrace three-dimensional model ND as shown in Figure 3 .

[0069] Step eight, export the generated tailrace three-dimensional model ND in stp format.

Claims

1. A method for creating a three-dimensional model of a tailrace channel, characterized in that, include: Step S1: Collect tailrace channel parameters and convert the collected tailrace channel parameters into a contour dataset, wherein the contour data includes the spatial position parameters and geometric parameters of the contour shape; Step S2: Transform the geometric parameters of the contour shape into the established contour center coordinate system based on the spatial position parameters of the contour; Step S3: Determine the contour type of each contour based on the contour shape geometric parameters in the contour center coordinate system; Step S4: Generate multiple coupling points at different feature locations based on the contour type; specifically, this includes: selecting coupling points from the feature points of the contour according to the types of the current contour and the subsequent contour; the feature points include the starting point, ending point, and corner points of the arc; Step S5: Generate a set of NURBS curves for each contour based on the contour shape geometry parameters in the contour center coordinate system; Step S6: Select a coupling strategy and connect the coupling points on different contours using NURBS curves to generate ridge lines; specifically including: (1) Generate a contour type list CT based on the contour type judgment result in step S3, and record the number of each contour in the contour type list. ; (2) Merge adjacent identical contours in the contour type list CT, and record the number range of each contour in each merged contour. ; (3) Merge adjacent identical contours in the merged contours again to form the final contour type grouping. ; The resulting outline type; (4) Connect the contour type groups according to the selected coupling strategy. The corresponding contour number range The coupling points of all the contours within the ridge form the ridge set L. ; Step S7: Generate NURBS surfaces for the tailrace channel based on the contour NURBS curves and generated ridges; stitch the generated NURBS surfaces together to generate a 3D model of the tailrace channel; specifically including: (1) Obtain the NURBS curve set of the contour Ridge set L Grouping of contour types after merging and blending ; (2) Grouping according to contour type The corresponding contour number range The NURBS surface lofting algorithm is used to call the contour NURBS curve set. NURBS curves and ridge sets L The ridge line segments form the NURBS surface model of the tailrace channel. ; (3) Perform surface splicing on the NURBS surface model to generate a three-dimensional model of the tailrace channel.

2. The method for creating a three-dimensional model of the tailrace channel according to claim 1, characterized in that, The spatial position parameters of the contour mentioned in step S1 include the coordinates (x, y, z) of the contour in the world coordinate system, and the geometric parameters of the contour shape include the rotation angles θ, β, and γ of the plane containing the contour about the x, y, and z axes, the width W of the contour, the height H of the contour, the chamfer radius R1 of the upper half of the contour, and the chamfer radius R2 of the lower half of the contour.

3. The method for creating a three-dimensional model of the tailrace channel according to claim 1, characterized in that, The contour types mentioned in step S3 include circles, single-sided semi-circular rectangles, double-sided semi-circular rectangles, single-sided semi-circular rectangles, double-sided semi-circular rectangles, single-sided rounded rectangles, and double-sided rounded rectangles.

4. The method for creating a three-dimensional model of the tailrace channel according to claim 1, characterized in that, Export the generated tailrace channel 3D model in STP format.

5. A tailrace flow channel three-dimensional model creation system, used to implement the tailrace flow channel three-dimensional model creation method as described in any one of claims 1-4, characterized in that, It includes a data conversion module, a data preprocessing module, a cross-section contour recognition module, a coupling point generation module, a cross-section contour generation module, a model lofting generation module, and a model export module; The data conversion module is used to collect tailrace channel parameters and convert the collected tailrace channel parameters into contour dataset parameters; the contour data includes the spatial position parameters and geometric parameters of the contour. The data preprocessing module is used to transform the geometric parameters of the contour shape into the established contour center coordinate system based on the spatial position parameters of the contour in the contour dataset. The cross-sectional contour recognition module is used to determine the type of each contour based on the geometric parameters of the contour shape in the contour center coordinate system. The coupling point generation module generates multiple coupling points at different feature locations based on the contour type. The cross-sectional profile generation module generates NURBS curves for each profile based on the geometric parameters of the profile shape in the profile center coordinate system, and establishes a set of NURBS curves. The model lofting generation module is used to connect corresponding coupling points on different cross-sectional contours using NURBS curves to generate a set of ridge lines according to the selected coupling strategy; generate NURBS surfaces on the tailrace channel surface based on the NURBS curves of the contours and the generated ridge lines; and stitch the generated NURBS surfaces together to generate a three-dimensional model of the tailrace channel. The model export module is used to export the generated tailrace channel 3D model according to the set export format.

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