A digital modeling method and system for reverse reconstruction of industrial drawings

Abstract

The present invention discloses a digital modeling method and system for reverse reconstruction of industrial drawings, which relates to the field of digital reverse modeling technology, including: using laser scanning equipment to longitudinally scan a workpiece; calculating the surface complexity of the workpiece in the longitudinal direction; determining the slice density data during reverse reconstruction of the workpiece; performing transverse scanning on the workpiece; establishing a one-to-one correspondence between a closed transverse projection curve and the longitudinal height of the workpiece; sorting the closed transverse projection curves of the workpiece; performing smooth transition lofting on the closed transverse projection curves of all the workpieces; and materializing the closed outer surface of the workpiece. The present invention has the advantages that the scanning accuracy during reverse reconstruction scanning can be reasonably allocated under the limitation of hardware equipment, thereby effectively ensuring that the accuracy during reverse modeling is maximized under the accuracy limitation of the hardware equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of digital reverse modeling, and in particular to a digital modeling method and system for reverse reconstruction of industrial drawings. Background Art

[0002] Reverse modeling is a way of reverse modeling based on existing artifacts in reality. The technology of reverse modeling is developing rapidly, and it is gradually maturing. Reverse modeling technology includes: point cloud reverse modeling, photo reverse modeling, 3D scanning reverse modeling and other technologies. Reverse modeling is a different modeling idea. No matter which reverse modeling technology is used, it will eventually be converted into a digital model of polygons or triangles. The generated model can be used for digital visualization, film and television, games and other scientific research.

[0003] In three-dimensional scanning reverse modeling, the accuracy of reverse modeling depends on the number of scanning layers. However, due to the scanning hardware limitations of the scanning equipment and the computing power limitations of the modeling computer, there is often an upper limit to the number of scanning layers of the workpiece. However, in the prior art, there is a lack of intelligent analysis and calculation methods for the number of scanning layers based on the complexity of the workpiece surface shape, making it difficult to maximize the modeling accuracy under the limitations of hardware equipment. Summary of the invention

[0004] In order to solve the above technical problems, a digital modeling method and system for reverse reconstruction of industrial drawings are provided. This technical solution solves the problem that the above-mentioned prior art lacks an intelligent analysis and calculation method for the number of scanning layers based on the complexity of the workpiece surface shape, and it is difficult to maximize the modeling accuracy under the limitations of hardware equipment.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0006] A digital modeling method for reverse reconstruction of industrial drawings, comprising:

[0007] Use laser scanning equipment to longitudinally scan the workpiece to obtain several longitudinal projection lines of the workpiece;

[0008] Calculate the surface complexity of the workpiece in the longitudinal direction based on several longitudinal projection lines of the workpiece;

[0009] Based on the surface complexity of the workpiece in the longitudinal direction, the slice scanning thickness in the longitudinal direction during reverse reconstruction of the workpiece is determined and recorded as slice density data;

[0010] Based on the slice density data, the workpiece is scanned transversely to obtain several closed transverse projection curves of the workpiece;

[0011] Establish a one-to-one correspondence between the closed transverse projection curve and the longitudinal height of the workpiece;

[0012] Based on the one-to-one correspondence between the closed transverse projection curves of the workpiece and the longitudinal height of the workpiece, the closed transverse projection curves of the workpiece are sorted in order from low to high;

[0013] Perform smooth transition lofting on the closed transverse projection curves of all workpieces to obtain the closed outer surface of the workpiece;

[0014] The closed outer surface of the workpiece is solidified to obtain a solidified model of the workpiece.

[0015] Preferably, the step of longitudinally scanning the workpiece using a laser scanning device to obtain a plurality of longitudinal projection lines of the workpiece specifically includes:

[0016] At intervals of 1°, 360° all-round longitudinal distance measurement is performed on the workpiece surface to obtain distance measurement data of several longitudinal projection lines of the workpiece surface;

[0017] Based on the distance measurement data of several longitudinal projection lines of the workpiece surface, the distance from each point on the longitudinal projection line to the workpiece rotation axis is calculated and recorded as the workpiece surface distance data;

[0018] The workpiece longitudinal height is taken as the X-axis coordinate, the workpiece surface distance data is taken as the Y-axis coordinate, and the workpiece surface data-workpiece longitudinal height change curve is fitted based on the workpiece surface distance data;

[0019] Based on the workpiece surface data - workpiece longitudinal height change curve, determine the workpiece surface data - workpiece longitudinal height change curve expression;

[0020] The calculation formula of the workpiece surface distance data is:

[0021]

[0022] In the formula, is the workpiece surface distance data at a height of h on the longitudinal projection line, is the distance from the workpiece surface to the detection head at a height of h measured by the laser scanning device, It is the distance between the workpiece rotation axis and the detection head.

[0023] Preferably, the calculating the surface complexity of the workpiece in the longitudinal direction based on a plurality of longitudinal projection lines of the workpiece specifically comprises:

[0024] Derivative the workpiece surface data-workpiece longitudinal height change curve expression to obtain the workpiece surface data-workpiece longitudinal height change degree;

[0025] Based on all workpiece surface data - the longitudinal height variation of the workpiece, the surface complexity of the workpiece in the longitudinal direction is calculated through the complex index calculation formula;

[0026] The calculation formula of the complex index is:

[0027]

[0028] In the formula, is the surface complexity of the workpiece at the longitudinal height h, It is the derivative of the expression of the i-th workpiece surface data - workpiece longitudinal height change curve at the longitudinal height h.

[0029] Preferably, the determining of the slice scanning thickness in the longitudinal direction of the workpiece during reverse reconstruction based on the surface complexity of the workpiece in the longitudinal direction, recorded as slice density data, specifically includes:

[0030] Determine the accuracy of reverse reconstruction of the workpiece, and determine the total number of layers of lateral scanning of the workpiece based on the accuracy of reverse reconstruction of the workpiece;

[0031] Set the base thickness;

[0032] According to the reference thickness, the workpiece is longitudinally divided into a number of scanning reference slices;

[0033] Based on the surface complexity of the workpiece in the longitudinal direction and the total number of layers of the workpiece in the transverse scanning, the number of transverse scanning layers in each scanning reference slice is determined;

[0034] Calculating the slice scanning thickness in each scanning reference slice based on the number of transverse scanning layers in each scanning reference slice;

[0035] The calculation formula for the slice scanning thickness within the scanning reference slice is:

[0036]

[0037] In the formula, is the slice scanning thickness within the j-th scanning reference slice, is the base thickness, is the number of transverse scanning layers in the jth scanning reference slice.

[0038] Preferably, the calculation formula for determining the number of transverse scanning layers in each scanning reference slice based on the surface complexity of the workpiece in the longitudinal direction and the total number of transverse scanning layers of the workpiece is:

[0039]

[0040] In the formula, is the total height of the workpiece, is the longitudinal height of the lower edge of the j-th scan reference slice, is the total number of layers scanned laterally on the workpiece, For all Perform the summation.

[0041] Preferably, the step of performing transverse scanning on the workpiece based on the slice density data to obtain a plurality of closed transverse projection curves of the workpiece specifically includes:

[0042] Based on the slice density data, determine the longitudinal height of each transverse scanning line on the workpiece;

[0043] The height of the transverse scanning detection head is adjusted sequentially to the longitudinal height of each transverse scanning line, and the transverse distance measurement is performed from the front and back sides of the workpiece surface respectively to obtain the forward projection half curve and the reverse projection half curve;

[0044] The forward projection half curve and the reverse projection half curve are combined to generate a closed transverse projection curve of the workpiece at the corresponding longitudinal height.

[0045] Furthermore, a digital modeling system for reverse reconstruction of industrial drawings is proposed, which is used to implement the digital modeling method for reverse reconstruction of industrial drawings as described above, including:

[0046] A laser scanning device, wherein the laser scanning device is used to perform longitudinal and transverse scanning on a workpiece;

[0047] A surface complexity module, the surface complexity module is electrically connected to the laser scanning device, and is used to calculate the surface complexity of the workpiece in the longitudinal direction based on a number of longitudinal projection lines of the workpiece and determine the slice scanning thickness in the longitudinal direction during reverse reconstruction of the workpiece based on the surface complexity of the workpiece in the longitudinal direction, which is recorded as slice density data;

[0048] A modeling module, the modeling module is electrically connected to the laser scanning device, the modeling module is used to establish a one-to-one correspondence between a closed transverse projection curve and a longitudinal height of a workpiece, based on the one-to-one correspondence between the closed transverse projection curve of the workpiece and the longitudinal height of the workpiece, sort the closed transverse projection curves of the workpiece in order from low to high, perform smooth transition lofting on the closed transverse projection curves of all the workpieces, obtain the closed outer surface of the workpiece, and solidify the closed outer surface of the workpiece to obtain a solidified model of the workpiece.

[0049] Optionally, the laser scanning device includes:

[0050] A longitudinal distance measuring unit, wherein the longitudinal distance measuring unit is used to perform longitudinal distance measurement on the surface of a workpiece;

[0051] A lateral distance measuring unit is used to perform lateral distance measurement on the surface of a workpiece.

[0052] Optionally, the surface complexity module internally integrates:

[0053] A first calculation unit, the first calculation unit is used to calculate the surface complexity of the workpiece in the longitudinal direction based on a plurality of longitudinal projection lines of the workpiece;

[0054] The second calculation unit is used to determine the slice scanning thickness in the longitudinal direction of the workpiece during reverse reconstruction based on the surface complexity of the workpiece in the longitudinal direction, which is recorded as slice density data.

[0055] Optionally, the modeling module internally integrates:

[0056] A curve combining unit, the curve combining unit is used to combine the forward projection half curve and the reverse projection half curve to generate a closed transverse projection curve of the workpiece at a corresponding longitudinal height;

[0057] A curve sorting unit, the curve sorting unit is used to sort the closed transverse projection curves of the workpiece from low to high in order based on a one-to-one correspondence between the closed transverse projection curves of the workpiece and the longitudinal heights of the workpiece;

[0058] A curved surface stitching unit, which is used to smoothly transition and lay out the closed transverse projection curves of all workpieces to obtain the closed outer surface curved surface of the workpiece;

[0059] The solid modeling unit is used to solidify the closed outer surface of the workpiece to obtain a solidified model of the workpiece.

[0060] Compared with the prior art, the present invention has the following beneficial effects:

[0061] The present invention proposes a digital modeling solution for reverse reconstruction of industrial drawings. The solution collects longitudinal projection lines of the workpiece surface and reflects the complexity of the workpiece surface based on the rapidity of change of several longitudinal projection lines of the workpiece surface. The number of scanning layers is increased for areas with high complexity, and the number of scanning layers is reduced for areas with low complexity. In this way, the scanning accuracy of the reverse reconstruction scan can be reasonably allocated under the limitation of the hardware equipment, thereby effectively ensuring that the accuracy of the reverse modeling is maximized under the accuracy limitation of the hardware equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 A flow chart of the digital modeling method for reverse reconstruction of industrial drawings proposed by the present invention;

[0063] Figure 2A flow chart of a method for obtaining a plurality of longitudinal projection lines of a workpiece in the present invention;

[0064] Figure 3 A flow chart of a method for calculating the surface complexity of a workpiece in the longitudinal direction in the present invention;

[0065] Figure 4 A flow chart of a method for determining the slice scanning thickness in the longitudinal direction during reverse reconstruction of a workpiece in the present invention;

[0066] Figure 5 It is a flow chart of the method for obtaining a closed transverse projection curve of a workpiece in the present invention;

[0067] Figure 6 This is a structural block diagram of the digital modeling system for reverse reconstruction of industrial drawings proposed by the present invention. DETAILED DESCRIPTION

[0068] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0069] Reference Figure 1 As shown, a digital modeling method for reverse reconstruction of industrial drawings comprises:

[0070] Use laser scanning equipment to longitudinally scan the workpiece to obtain several longitudinal projection lines of the workpiece;

[0071] Calculate the surface complexity of the workpiece in the longitudinal direction based on several longitudinal projection lines of the workpiece;

[0072] Based on the surface complexity of the workpiece in the longitudinal direction, the slice scanning thickness in the longitudinal direction during reverse reconstruction of the workpiece is determined and recorded as slice density data;

[0073] Based on the slice density data, the workpiece is scanned transversely to obtain several closed transverse projection curves of the workpiece;

[0074] Establish a one-to-one correspondence between the closed transverse projection curve and the longitudinal height of the workpiece;

[0075] Based on the one-to-one correspondence between the closed transverse projection curves of the workpiece and the longitudinal height of the workpiece, the closed transverse projection curves of the workpiece are sorted in order from low to high;

[0076] Perform smooth transition lofting on the closed transverse projection curves of all workpieces to obtain the closed outer surface of the workpiece;

[0077] The closed outer surface of the workpiece is solidified to obtain a solidified model of the workpiece.

[0078] This solution collects longitudinal projection lines of the workpiece surface and reflects the complexity of the workpiece surface based on the rapidity of change of several longitudinal projection lines on the workpiece surface. The number of scanning layers is increased for areas with high complexity and reduced for areas with low complexity.

[0079] Reference Figure 2 As shown, the use of a laser scanning device to longitudinally scan a workpiece to obtain a plurality of longitudinal projection lines of the workpiece specifically includes:

[0080] At intervals of 1°, 360° all-round longitudinal distance measurement is performed on the workpiece surface to obtain distance measurement data of several longitudinal projection lines of the workpiece surface;

[0081] Based on the distance measurement data of several longitudinal projection lines of the workpiece surface, the distance from each point on the longitudinal projection line to the workpiece rotation axis is calculated and recorded as the workpiece surface distance data;

[0082] The workpiece longitudinal height is taken as the X-axis coordinate, the workpiece surface distance data is taken as the Y-axis coordinate, and the workpiece surface data-workpiece longitudinal height change curve is fitted based on the workpiece surface distance data;

[0083] Based on the workpiece surface data - workpiece longitudinal height change curve, determine the workpiece surface data - workpiece longitudinal height change curve expression;

[0084] The calculation formula of the workpiece surface distance data is:

[0085]

[0086] In the formula, is the workpiece surface distance data at a height of h on the longitudinal projection line, is the distance from the workpiece surface to the detection head at a height of h measured by the laser scanning device, It is the distance between the workpiece rotation axis and the detection head.

[0087] Reference Figure 3 As shown, the calculation of the surface complexity of the workpiece in the longitudinal direction based on a plurality of longitudinal projection lines of the workpiece specifically includes:

[0088] Derivative the workpiece surface data-workpiece longitudinal height change curve expression to obtain the workpiece surface data-workpiece longitudinal height change degree;

[0089] Based on all workpiece surface data - the longitudinal height variation of the workpiece, the surface complexity of the workpiece in the longitudinal direction is calculated through the complex index calculation formula;

[0090] The calculation formula of the complex index is:

[0091]

[0092] In the formula, is the surface complexity of the workpiece at the longitudinal height h, It is the derivative of the expression of the i-th workpiece surface data - workpiece longitudinal height change curve at the longitudinal height h.

[0093] It can be understood that the greater the rate of change of the distance from the workpiece surface to the workpiece rotation axis, the steeper the change of the workpiece surface. By summing up the rate of change of all workpiece surface data at the same height - the workpiece longitudinal height change curve, the complexity index of the workpiece surface at this height is used. The larger the complexity index at this height, the more complex the surface of the workpiece at this height.

[0094] Reference Figure 4 As shown, the slice scanning thickness in the longitudinal direction of the workpiece during reverse reconstruction is determined based on the surface complexity of the workpiece in the longitudinal direction, which is recorded as slice density data and specifically includes:

[0095] Determine the accuracy of reverse reconstruction of the workpiece, and determine the total number of layers of lateral scanning of the workpiece based on the accuracy of reverse reconstruction of the workpiece;

[0096] Set the base thickness;

[0097] According to the reference thickness, the workpiece is longitudinally divided into a number of scanning reference slices;

[0098] Based on the surface complexity of the workpiece in the longitudinal direction and the total number of layers of the workpiece in the transverse scanning, the number of transverse scanning layers in each scanning reference slice is determined;

[0099] Calculating the slice scanning thickness in each scanning reference slice based on the number of transverse scanning layers in each scanning reference slice;

[0100] The calculation formula for the slice scanning thickness within the scanning reference slice is:

[0101]

[0102] In the formula, is the slice scanning thickness within the j-th scanning reference slice, is the base thickness, is the number of transverse scanning layers in the jth scanning reference slice.

[0103] The calculation formula for determining the number of transverse scanning layers in each scanning reference slice based on the surface complexity of the workpiece in the longitudinal direction and the total number of transverse scanning layers of the workpiece is:

[0104]

[0105] In the formula, is the total height of the workpiece, is the longitudinal height of the lower edge of the j-th scan reference slice, is the total number of layers scanned laterally on the workpiece, For all Perform the summation.

[0106] By calculating the ratio of the sum of the surface complexity in each scanned reference slice to the sum of all surface complexities within the full workpiece height and allocating the available scanning layers, the scanning accuracy can be effectively and intelligently adjusted based on the surface complexity of the workpiece, thereby maximizing the accuracy of reverse modeling within the accuracy limit of the hardware equipment.

[0107] Reference Figure 5 As shown, the process of performing a transverse scan on the workpiece based on the slice density data to obtain a plurality of closed transverse projection curves of the workpiece specifically includes:

[0108] Based on the slice density data, determine the longitudinal height of each transverse scanning line on the workpiece;

[0109] The height of the transverse scanning detection head is adjusted sequentially to the longitudinal height of each transverse scanning line, and the transverse distance measurement is performed from the front and back sides of the workpiece surface respectively to obtain the forward projection half curve and the reverse projection half curve;

[0110] The forward projection half curve and the reverse projection half curve are combined to generate a closed transverse projection curve of the workpiece at the corresponding longitudinal height.

[0111] Furthermore, based on the same inventive concept as the digital modeling method for reverse reconstruction of industrial drawings, the present solution also proposes a digital modeling system for reverse reconstruction of industrial drawings, comprising:

[0112] A laser scanning device, wherein the laser scanning device is used to perform longitudinal and transverse scanning on a workpiece;

[0113] A surface complexity module, the surface complexity module is electrically connected to the laser scanning device, and is used to calculate the surface complexity of the workpiece in the longitudinal direction based on a number of longitudinal projection lines of the workpiece and determine the slice scanning thickness in the longitudinal direction during reverse reconstruction of the workpiece based on the surface complexity of the workpiece in the longitudinal direction, which is recorded as slice density data;

[0114] A modeling module, the modeling module is electrically connected to the laser scanning device, the modeling module is used to establish a one-to-one correspondence between a closed transverse projection curve and a longitudinal height of a workpiece, based on the one-to-one correspondence between the closed transverse projection curve of the workpiece and the longitudinal height of the workpiece, sort the closed transverse projection curves of the workpiece in order from low to high, perform smooth transition lofting on the closed transverse projection curves of all the workpieces, obtain the closed outer surface of the workpiece, and solidify the closed outer surface of the workpiece to obtain a solidified model of the workpiece.

[0115] The laser scanning device comprises:

[0116] A longitudinal distance measuring unit, wherein the longitudinal distance measuring unit is used to perform longitudinal distance measurement on the surface of a workpiece;

[0117] A lateral distance measuring unit is used to perform lateral distance measurement on the surface of a workpiece.

[0118] Optionally, the surface complexity module internally integrates:

[0119] A first calculation unit, the first calculation unit is used to calculate the surface complexity of the workpiece in the longitudinal direction based on a plurality of longitudinal projection lines of the workpiece;

[0120] The second calculation unit is used to determine the slice scanning thickness in the longitudinal direction of the workpiece during reverse reconstruction based on the surface complexity of the workpiece in the longitudinal direction, which is recorded as slice density data.

[0121] The modeling module internally integrates:

[0122] A curve combining unit, the curve combining unit is used to combine the forward projection half curve and the reverse projection half curve to generate a closed transverse projection curve of the workpiece at a corresponding longitudinal height;

[0123] A curve sorting unit, the curve sorting unit is used to sort the closed transverse projection curves of the workpiece from low to high in order based on a one-to-one correspondence between the closed transverse projection curves of the workpiece and the longitudinal heights of the workpiece;

[0124] A curved surface stitching unit, which is used to smoothly transition and lay out the closed transverse projection curves of all workpieces to obtain the closed outer surface curved surface of the workpiece;

[0125] The solid modeling unit is used to solidify the closed outer surface of the workpiece to obtain a solidified model of the workpiece.

[0126] The use process of the digital modeling system for reverse reconstruction of industrial drawings is as follows:

[0127] Step 1: The longitudinal distance measuring unit performs 360° full-scale longitudinal distance measurement on the workpiece surface at intervals of 1° to obtain distance measurement data of several longitudinal projection lines of the workpiece surface;

[0128] Step 2: The first calculation unit calculates the distance from each point on the longitudinal projection line to the axis of rotation of the workpiece based on the distance measurement data of a plurality of longitudinal projection lines of the workpiece surface, and records it as the workpiece surface distance data. The longitudinal height of the workpiece is taken as the X-axis coordinate, and the workpiece surface distance data is taken as the Y-axis coordinate. Based on the workpiece surface distance data, a workpiece surface data-workpiece longitudinal height change curve is fitted. Based on the workpiece surface data-workpiece longitudinal height change curve, an expression of the workpiece surface data-workpiece longitudinal height change curve is determined. The expression of the workpiece surface data-workpiece longitudinal height change curve is derived to obtain the workpiece surface data-workpiece longitudinal height change degree. Based on all the workpiece surface data-workpiece longitudinal height change degrees, the surface complexity of the workpiece in the longitudinal direction is calculated by a complex index calculation formula.

[0129] Step 3: The second calculation unit determines the accuracy of the reverse reconstruction of the workpiece, determines the total number of layers of the workpiece transverse scanning based on the accuracy of the reverse reconstruction of the workpiece, sets a reference thickness, divides the workpiece longitudinally into a plurality of scanning reference slices according to the reference thickness, determines the number of transverse scanning layers in each scanning reference slice based on the surface complexity of the workpiece in the longitudinal direction and the total number of layers of the workpiece transverse scanning, and calculates the slice scanning thickness in each scanning reference slice based on the number of transverse scanning layers in each scanning reference slice;

[0130] Step 4: The lateral distance measuring unit determines the longitudinal height of each lateral scanning line on the workpiece based on the slice density data, adjusts the height of the lateral scanning probe to the longitudinal height of each lateral scanning line in turn, and performs lateral distance measurement on the workpiece surface from the front and back sides respectively to obtain the forward projection half curve and the reverse projection half curve.

[0131] Step 5: The curve combining unit combines the forward projection half curve and the reverse projection half curve to generate a closed transverse projection curve of the workpiece at the corresponding longitudinal height;

[0132] Step 6: The curve sorting unit sorts the closed transverse projection curves of the workpiece from low to high based on the one-to-one correspondence between the closed transverse projection curves of the workpiece and the longitudinal heights of the workpiece;

[0133] Step 7: The surface stitching unit performs smooth transition lofting on the closed transverse projection curves of all workpieces to obtain the closed outer surface of the workpiece;

[0134] Step 8: The solid modeling unit solidifies the closed outer surface of the workpiece to obtain a solidified model of the workpiece.

[0135] In summary, the advantages of the present invention are that the scanning accuracy during reverse reconstruction scanning can be reasonably allocated under the limitation of hardware equipment, thereby effectively ensuring that the accuracy of reverse modeling is maximized under the accuracy limitation of hardware equipment.

[0136] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A digital modeling method for reverse reconstruction of industrial drawings, characterized in that: include: Use laser scanning equipment to longitudinally scan the workpiece to obtain several longitudinal projection lines of the workpiece; Calculate the surface complexity of the workpiece in the longitudinal direction based on several longitudinal projection lines of the workpiece; Based on the surface complexity of the workpiece in the longitudinal direction, the slice scanning thickness in the longitudinal direction during reverse reconstruction of the workpiece is determined and recorded as slice density data; Based on the slice density data, the workpiece is scanned transversely to obtain several closed transverse projection curves of the workpiece; Establish a one-to-one correspondence between the closed transverse projection curve and the longitudinal height of the workpiece; Based on the one-to-one correspondence between the closed transverse projection curves of the workpiece and the longitudinal height of the workpiece, the closed transverse projection curves of the workpiece are sorted in order from low to high; Perform smooth transition lofting on the closed transverse projection curves of all workpieces to obtain the closed outer surface of the workpiece; Solidify the closed outer surface of the workpiece to obtain a solid model of the workpiece; The step of calculating the surface complexity of the workpiece in the longitudinal direction based on a plurality of longitudinal projection lines of the workpiece specifically includes: Derivative the workpiece surface data-workpiece longitudinal height change curve expression to obtain the workpiece surface data-workpiece longitudinal height change degree; Based on all workpiece surface data - the longitudinal height variation of the workpiece, the surface complexity of the workpiece in the longitudinal direction is calculated through the complex index calculation formula; The calculation formula of the complex index is: In the formula, is the surface complexity of the workpiece at the longitudinal height h, is the derivative of the expression of the i-th workpiece surface data-workpiece longitudinal height change curve at the longitudinal height h; The determination of the slice scanning thickness in the longitudinal direction of the workpiece during reverse reconstruction based on the surface complexity of the workpiece in the longitudinal direction, recorded as slice density data, specifically includes: Determine the accuracy of reverse reconstruction of the workpiece, and determine the total number of layers of lateral scanning of the workpiece based on the accuracy of reverse reconstruction of the workpiece; Set the base thickness; According to the reference thickness, the workpiece is longitudinally divided into a number of scanning reference slices; Based on the surface complexity of the workpiece in the longitudinal direction and the total number of layers of the workpiece in the transverse scanning, the number of transverse scanning layers in each scanning reference slice is determined; Calculating the slice scanning thickness in each scanning reference slice based on the number of transverse scanning layers in each scanning reference slice; The calculation formula for the slice scanning thickness within the scanning reference slice is: In the formula, is the slice scanning thickness within the j-th scanning reference slice, is the base thickness, is the number of transverse scan layers within the jth scan reference slice; The calculation formula for determining the number of transverse scanning layers in each scanning reference slice based on the surface complexity of the workpiece in the longitudinal direction and the total number of transverse scanning layers of the workpiece is: In the formula, is the total height of the workpiece, is the longitudinal height of the lower edge of the j-th scan reference slice, is the total number of layers scanned laterally on the workpiece, For all Perform the summation.

2. A digital modeling method for reverse reconstruction of industrial drawings according to claim 1, characterized in that: The method of using a laser scanning device to longitudinally scan the workpiece to obtain a plurality of longitudinal projection lines of the workpiece specifically includes: At intervals of 1°, 360° all-round longitudinal distance measurement is performed on the workpiece surface to obtain distance measurement data of several longitudinal projection lines of the workpiece surface; Based on the distance measurement data of several longitudinal projection lines of the workpiece surface, the distance from each point on the longitudinal projection line to the workpiece rotation axis is calculated and recorded as the workpiece surface distance data; The workpiece longitudinal height is taken as the X-axis coordinate, the workpiece surface distance data is taken as the Y-axis coordinate, and the workpiece surface data-workpiece longitudinal height change curve is fitted based on the workpiece surface distance data; Based on the workpiece surface data - workpiece longitudinal height change curve, determine the workpiece surface data - workpiece longitudinal height change curve expression; The calculation formula of the workpiece surface distance data is: In the formula, is the workpiece surface distance data at a height of h on the longitudinal projection line, is the distance from the workpiece surface to the detection head at a height of h measured by the laser scanning device, It is the distance between the workpiece rotation axis and the detection head.

3. A digital modeling method for reverse reconstruction of industrial drawings according to claim 1, characterized in that: The step of performing transverse scanning on the workpiece based on the slice density data to obtain a plurality of closed transverse projection curves of the workpiece specifically includes: Based on the slice density data, determine the longitudinal height of each transverse scanning line on the workpiece; The height of the transverse scanning detection head is adjusted sequentially to the longitudinal height of each transverse scanning line, and the transverse distance measurement is performed from the front and back sides of the workpiece surface respectively to obtain the forward projection half curve and the reverse projection half curve; The forward projection half curve and the reverse projection half curve are combined to generate a closed transverse projection curve of the workpiece at the corresponding longitudinal height.

4. A digital modeling system for reverse reconstruction of industrial drawings, characterized in that: A digital modeling method for reverse reconstruction of industrial drawings according to any one of claims 1 to 3, comprising: A laser scanning device, wherein the laser scanning device is used to perform longitudinal and transverse scanning on a workpiece; A surface complexity module, the surface complexity module is electrically connected to the laser scanning device, and is used to calculate the surface complexity of the workpiece in the longitudinal direction based on a number of longitudinal projection lines of the workpiece and determine the slice scanning thickness in the longitudinal direction during reverse reconstruction of the workpiece based on the surface complexity of the workpiece in the longitudinal direction, which is recorded as slice density data; A modeling module, the modeling module is electrically connected to the laser scanning device, and the modeling module is used to establish a one-to-one correspondence between a closed transverse projection curve and a longitudinal height of a workpiece, sort the closed transverse projection curves of the workpiece from low to high based on the one-to-one correspondence between the closed transverse projection curves of the workpiece and the longitudinal height of the workpiece, perform smooth transition lofting on the closed transverse projection curves of all the workpieces, obtain a closed outer surface of the workpiece, and solidify the closed outer surface of the workpiece to obtain a solidified model of the workpiece; The surface complexity module internally integrates: A first calculation unit, the first calculation unit is used to calculate the surface complexity of the workpiece in the longitudinal direction based on a plurality of longitudinal projection lines of the workpiece; A second calculation unit, the second calculation unit is used to determine the slice scanning thickness in the longitudinal direction of the workpiece during reverse reconstruction based on the surface complexity of the workpiece in the longitudinal direction, recorded as slice density data; The modeling module internally integrates: A curve combining unit, the curve combining unit is used to combine the forward projection half curve and the reverse projection half curve to generate a closed transverse projection curve of the workpiece at a corresponding longitudinal height; A curve sorting unit, the curve sorting unit is used to sort the closed transverse projection curves of the workpiece from low to high in order based on a one-to-one correspondence between the closed transverse projection curves of the workpiece and the longitudinal heights of the workpiece; A curved surface stitching unit, which is used to smoothly transition and lay out the closed transverse projection curves of all workpieces to obtain the closed outer surface curved surface of the workpiece; The solid modeling unit is used to solidify the closed outer surface of the workpiece to obtain a solidified model of the workpiece.

5. A digital modeling system for reverse reconstruction of industrial drawings according to claim 4, characterized in that: The laser scanning device comprises: A longitudinal distance measuring unit, wherein the longitudinal distance measuring unit is used to perform longitudinal distance measurement on the surface of a workpiece; A lateral distance measuring unit is used to perform lateral distance measurement on the surface of a workpiece.

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