CN107358615B

CN107358615B - CAD edge area detection method and system

Info

Publication number: CN107358615B
Application number: CN201710425165.7A
Authority: CN
Inventors: 惠晴雨; 甘田; 杨波
Original assignee: Bullmer Electromechanical Technology Co Ltd
Current assignee: Bullmer Electromechanical Technology Co Ltd
Priority date: 2017-06-07
Filing date: 2017-06-07
Publication date: 2020-05-05
Anticipated expiration: 2037-06-07
Also published as: CN107358615A

Abstract

The invention discloses a CAD edge area detection method and a CAD edge area detection system, which are used for solving the problems of long time consumption and low efficiency of the existing CAD edge area detection technology. The method comprises the following steps: s1, establishing a tree model based on a square in the cutting area; s2, inserting the cutting points into the tree model; and S3, judging whether the distance value between the cutting point and the cut point within the preset distance in the tree model is smaller than a critical value, if so, judging as a critical area. The method has high calculation speed, can quickly identify the critical area graph, and provides good performance guarantee for other identified algorithm operations.

Description

CAD edge area detection method and system

Technical Field

The invention relates to a CAD detection technology, in particular to a CAD edge area detection method and a CAD edge area detection system.

Background

CAD is computer aided design, garment CAD is computer aided garment design, and generally includes creation design (style, color, garment accessories, etc.), appearance, stacking, layout, etc. The clothing CAD starts to develop in the 70 th of the 20 th century, and a clothing CAD system consists of two parts, namely hardware and software.

A large number of styles and designs can be stored in the computer for the designer to select and modify, and the design process can be greatly simplified. Because the reference data is more, the imagination and creativity of designers are enriched. The clothing CAD system closely combines the design thought, experience and creativity of clothing designers with the powerful functions of a computer system, and is bound to become a main mode of modern clothing design, and clothing technology strongly supports clothing art.

The information of the clothing design is stored in the computer and can be called at any time, so that the management is convenient. Information transfer may also be performed over a network. The clothing industry has the advantages that the computer support nature quality is good, the benefit is high, and in turn, the adoption of a new electronic technology is more practically supported, and the progress of clothing technology is promoted.

In automatic cutting bed in-service use, to tailor the part that closes on the cut-off line, because reasons such as gas leakage, surface fabric characteristic, tailor the quality and descend to some extent usually, in current production, can reserve 2-3mm clearance between cut-parts and the cut-parts and alleviate this problem, can cause the surface fabric extravagant to a certain extent, some special surface fabrics simultaneously, the problem of quality decline is also hardly avoided in the reservation clearance.

In the software, all CAD cut pieces are composed of points, the concepts of curves and straight lines do not exist, each point only contains coordinate values in the x direction and the y direction which take millimeters as a unit, the average number of the total points of a window layout in the conventional production is about 1 ten thousand to 3 ten thousand, the distance judgment is carried out between each point and all the other points when the point moves forward, the calculation is time-consuming, the calculation is displayed in the actual production, simultaneously, because the concept of the curves does not exist on the framework, all the curves are composed of continuous points, all the long straight lines are only provided with two points, and the distance between the points cannot be judged whether the distance is critical or not under the condition.

The patent with publication number CN102509258A provides a method for rapidly cutting an elliptic curve in a rectangular window, for any given elliptic arc, the method successively passes through an integral bounding box of the elliptic arc, the inside and outside tests of the vertex of each divided quadrant elliptic arc and the vertex of the rectangular window relative to a quadrant elliptic arc segment and the relevance tests of the divided elliptic arc subsegments according to the occurrence probability and the required operation of various elliptic arcs, so as to eliminate the elliptic arcs which do not intersect with the rectangular window as much as possible with less operation; and (4) rapidly acquiring the intersection point of the elliptic arc and the rectangular window edge by a table look-up method for the residual elliptic arc which can be cut only by solving the intersection operation. The invention has the advantages that for any elliptic arc to be cut, the cutting result can be quickly obtained only by a plurality of times of shift, integer addition and subtraction or a small number of multiplication and division operations, and the elliptic arc cutting efficiency is greatly improved. However, the patent publication CN102509258A provides a fast clipping method for elliptic curves in rectangular windows, which has the problem of quality degradation when clipping the edge region.

Disclosure of Invention

The invention aims to provide a method and a system for detecting a CAD edge area, which are used for solving the problems of long time consumption and low efficiency of the existing CAD edge area detection technology.

In order to achieve the purpose, the invention adopts the technical scheme that:

a CAD edge area detection method, comprising the steps of:

s1, establishing a tree model based on a square in the cutting area;

s2, inserting the cutting points into the tree model;

and S3, judging whether the distance value between the cutting point and the cut point within the preset distance in the tree model is smaller than a critical value, if so, judging as a critical area.

Further, step S1 specifically includes:

establishing a square model in the cutting area;

dividing the middle points of the square models to obtain the next layer of square models;

judging whether the preset layer square model is divided or not, if so, stopping dividing; otherwise, continuing to divide the square model.

Further, step S2 specifically includes:

acquiring coordinates of the cutting points;

sequentially judging the region of the coordinate of the cutting point in each layer of square model;

and inserting the clipping point into the region to which the preset layer square model belongs.

Further, the method also comprises the following steps:

and S4, judging whether the distance value between the cutting point and the cutting line within the preset distance is smaller than a critical value, if so, judging as a critical area.

Further, step S4 specifically includes:

adding an insertion point on the cutting line according to a preset width;

calculating the distance value between the cutting point and each insertion point;

and selecting the shortest distance value as the distance value between the cutting point and the cutting line within the preset distance.

A CAD edge region detection system, comprising:

the modeling module is used for establishing a tree model based on a square in the cutting area;

the inserting module is used for inserting the cutting points into the tree model;

and the first judgment module is used for judging whether the distance value between the cutting point and the cut point within the preset distance in the tree-shaped model is smaller than a critical value or not, and if so, judging the cutting point to be a critical area.

Further, the modeling module includes:

the building unit is used for building a square model in the cutting area;

the dividing unit is used for dividing the middle point of the square model to obtain the next layer of square model;

the judging unit is used for judging whether the preset layer square model is divided or not, and if so, stopping dividing; otherwise, continuing to divide the square model.

Further, the insertion module includes:

the obtaining unit is used for obtaining the coordinates of the cutting points;

the judging unit is used for sequentially judging the region of the coordinate of the cutting point in each layer of square model;

and the determining unit is used for inserting the clipping point into the region to which the preset layer square model belongs.

Further, still include:

and the second judgment module is used for judging whether the distance value between the cutting point and the cutting line within the preset distance is smaller than a critical value or not, and if so, judging the cutting point to be a critical area.

Further, the second determination module includes:

the adding point unit is used for adding an inserting point on the cutting line according to a preset width;

the calculating unit is used for calculating the distance value between the cutting point and each inserting point;

and the selection unit is used for selecting the shortest distance value as the distance value between the cutting point and the cutting line within the preset distance.

Compared with the traditional technology, the invention has the following advantages:

the method has high calculation speed, can quickly identify the critical area graph, and provides good performance guarantee for other identified algorithm operations.

Drawings

FIG. 1 is a flowchart of a CAD edge area detection method according to an embodiment;

FIG. 2 is a block diagram of a CAD edge area detection system according to an embodiment;

FIG. 3 is a flowchart of a CAD edge area detection method according to the second embodiment;

FIG. 4 is a block diagram of a CAD edge area detection system according to a second embodiment;

FIG. 5 is a schematic diagram illustrating a tree model according to an embodiment;

FIG. 6 is a schematic diagram of a tree model provided in the first embodiment;

FIG. 7 is a schematic diagram illustrating insertion of a clipping point into a tree model according to an embodiment;

fig. 8 is a schematic diagram illustrating a principle of determining a clipping point and a clipped point within a predetermined distance according to an embodiment of the present invention.

Detailed Description

The following are specific embodiments of the present invention and are further described with reference to the drawings, but the present invention is not limited to these embodiments.

Example one

The embodiment provides a method for detecting a CAD edge area, as shown in fig. 1, including the steps of:

s11: establishing a tree model based on a square in the cutting area;

s12: inserting the cutting points into the tree model;

s13: and judging whether the distance value between the cutting point and the cut point within the preset distance in the tree model is smaller than a critical value, if so, judging as a critical area.

CAD is computer aided design. The clothing CAD refers to computer aided clothing design, and generally includes creation design (style, color, clothing accessories and the like), appearance making, stacking, layout and the like.

In the application of the automatic cutting bed, the cutting quality is reduced for the part close to the cutting line. In order to improve the clipping quality, correct identification of clipped clipping points near the current clipping point is a prerequisite for solving the problem.

The traditional method for detecting the critical area needs to judge the distance of each point, the calculation is time-consuming, the distance from the cutting point to the cutting line cannot be calculated, and whether the critical area exists cannot be judged.

The invention does not need to judge the distance of each point, has high calculation speed and can quickly identify the graph of the critical area.

In this embodiment, step S11 is to create a square-based tree model in the clipping region.

Wherein, step S11 specifically includes:

establishing a square model in the cutting area;

dividing the middle point of the square model to obtain the next layer of square model;

and judging whether the square model of the preset layer is divided, if so, stopping dividing, and otherwise, continuously dividing the square model.

The principle of building the tree model in step S11 is specifically shown in fig. 5:

setting a cutting area to abstract into a square with the area of 40mm x 40 mm;

separating the middle points of two sides of the square to obtain four squares of 20mm by 20 mm;

the four squares obtained were again divided from the midpoint to give 16 squares of 10mm by 10 mm.

As shown in fig. 6, fig. 6 is a schematic diagram of a tree model.

The 40mm by 40mm square model is a first layer square model;

the square model of 20mm by 20mm is a second layer square model;

the 10mm by 10mm square model is the third layer square model.

The tree model in the above example is a three-level tree model.

In practical situations, the number of the dividing layers can be adjusted according to specific situations.

Specifically, for example, we abstract the clipping to a 2560mm square model;

we can divide the square model into ten layers of tree models.

The table below lists the side lengths of the individual squares and the number of all the small squares for 2 to 10 layers.

The effect of adopting a seven-layer structure in actual test is better, speed and efficiency can be considered, and the accuracy can be well ensured.

In this embodiment, step S12 is to insert the clipping point into the tree model.

The tree model established in step S11 has multiple layers, and when the tree model is inserted in step S12, the narrowing of the range can be determined layer by layer, and finally the range is accurately determined within the square of the preset layer. Therefore, time can be greatly saved, and efficiency and accuracy are improved.

FIG. 7 is a schematic diagram illustrating the insertion of clipping points into a tree model, as shown in FIG. 7.

And establishing a coordinate axis by taking the O point as an origin, OE as a horizontal axis and OC as a vertical axis. O (0,0), C (0,40), D (40,40), E (40, 0).

The clipping point B3 to be inserted has coordinates (18, 14).

Since the horizontal and vertical axis coordinates of B3 are both less than 20, B3 is located at the lower right corner of the 40mm by 40mm square model, i.e., square OFGH.

Since both the horizontal and vertical axis coordinates of B3 are greater than 10, B3 is located at the upper left corner of the 20mm by 20mm square model, i.e., square GIJK.

GIJK is a 10mm by 10mm square model. Through the steps, the specific position of B3 in the square model at the third layer of the tree model can be quickly determined.

In practical application, we can insert the clipping point into the tree model by the above method. And the position of the coordinate of the cutting point on the square model of the preset layer of the tree model can be quickly determined.

In this embodiment, step S13 is to determine whether the distance between the clipping point and the clipped point within the preset distance in the tree model is smaller than the threshold, and if so, determine it as the threshold region.

In the conventional determination method, distance determination needs to be performed on all points every time a clipping point moves forward. In this embodiment, the cutting point only needs to be distance-determined from the cut point within the preset distance.

Fig. 8 is a schematic diagram illustrating a principle of determining a clipping point and a clipped point within a predetermined distance.

As shown in fig. 8, the lower right 9 squares are labeled, assuming that the point at the beginning of a is the clipped point and the point at the beginning of B is clipped to point B3. Since the cut points are inserted into the square of the preset layer square model, the points a1, a2, A3, a4, a5, a6, B1 and B2 are stored in the square.

The cut points within the preset distance of the point B3 are cut points in a square with the number of 1-9, namely A3, A4, A5, A6, B1 and B2. B1 and B2 are points of the same cut piece, and the distance value between the cutting point B3 and the A3, A4, A5 and A6 can be judged.

If the distance between the cutting point and the cut point is less than the critical value, the critical area is determined.

The critical value refers to a condition that a certain physical quantity is required to satisfy when an object is changed from one physical state to another physical state, and in this embodiment, refers to a maximum value determined as an edge region, that is, if a distance between a clipping point and a clipped point is smaller than the critical value, the part can be determined as the edge region, that is, the critical region.

Specifically, if the critical value of the system is set to be 5mm, the critical area is determined when the distance between the cutting point and the cut point is less than 5 mm.

According to the method provided by the embodiment, the positions of the cutting points are determined layer by layer through the tree model, the critical area is rapidly identified, and the calculation speed is increased. And (3) adopting a recursive classification idea and an optimization algorithm, finding the specified square at the highest speed and obtaining the cutting point contained in the square.

The present embodiment further provides a CAD edge area detection system, as shown in fig. 2, including:

the modeling module 21 is used for establishing a tree model based on a square in the cutting area;

an inserting module 22, configured to insert the clipping point into the tree model;

the first determining module 23 is configured to determine whether a distance value between the clipping point and a clipped point within a preset distance in the tree model is smaller than a critical value, and if so, determine the clipping point as a critical area.

In this embodiment, the modeling module 21 includes:

the building unit is used for building a square model in the cutting area;

In this embodiment, the insertion module 22 includes:

the acquisition unit is used for acquiring the coordinates of the cutting points;

The tree model established by the modeling module 21 has a plurality of layers, and the insertion module 22 can determine the reduction range layer by layer when inserting the tree model, and finally accurately determine the reduction range in the square of the preset layer. Therefore, time can be greatly saved, and efficiency and accuracy can be improved.

The conventional judgment module further needs to judge the distance between the cutting point and all the points before the cutting point. In this embodiment, the cutting point only needs to be distance-determined from the cut point within the preset distance.

According to the system provided by the embodiment, the positions of the cutting points are determined layer by layer through the tree model, the critical area is rapidly identified, and the calculation speed is increased. And (3) adopting a recursive classification idea and an optimization algorithm, finding the specified square at the highest speed and obtaining the cutting point contained in the square.

Example two

The embodiment provides a method for detecting a CAD edge area, as shown in fig. 3, including the steps of:

s31: establishing a tree model based on a square in the cutting area;

s32: inserting the cutting points into the tree model;

s33: judging whether the distance value between the cutting point and a cut point within a preset distance in the tree model is smaller than a critical value, if so, judging as a critical area;

s34: and judging whether the distance value between the cutting point and the cutting line in the preset distance is smaller than a critical value, if so, judging as a critical area.

The present embodiment is different from the first embodiment in that step S34 is further included.

In practical application, a straight line needs to be subjected to point adding processing, and the distance between a point and a point is ensured to be smaller than a critical value of a system.

Wherein, step S34 specifically includes:

adding an insertion point on the cutting line according to a preset width;

The specific principle is as follows:

assuming that a cutting line is cut from A to B, the minimum distance between a point P and the cutting line needs to be calculated, and the conventional method needs to connect the point A and the point B to form a straight line and then solve a perpendicular bisector from the point P to the straight line AB, which is not needed in the model.

In this embodiment, the point C, D, E, F, G, H, I, J, K, L, M is inserted into the point a to the point B according to a certain width, and then the distance from the point P to each point is calculated in a loop, where the minimum distance is the distance from the point P to the cutting line AB.

Wherein the width is not greater than a threshold value of the system.

In practical application, a point is inserted on the cutting line according to a preset width. The predetermined width is less than a threshold value. And calculating the distance value between the cutting point and each insertion point. And selecting the shortest distance value as the distance value from the cutting point to the cutting line.

The distance from the cutting point to the cutting line can be obtained without complex calculation, and the method is more convenient and faster.

The embodiment also provides a method and a system for detecting a CAD edge area, as shown in fig. 4, including:

a modeling module 41, configured to establish a tree model based on a square in the clipping area;

an inserting module 42, configured to insert the clipping point into the tree model;

the first determining module 43 is configured to determine whether a distance between the clipping point and a clipped point within a preset distance in the tree model is smaller than a threshold, and if so, determine the clipping point as a critical area.

The second determining module 44 is configured to determine whether a distance between the cutting point and the cutting line within the preset distance is smaller than a threshold value, and if so, determine the cutting point as a critical area.

The difference from the first embodiment is that a second determining module 44 is further included.

The second determining module 44 includes:

In practical application, in order to calculate the distance from a point to a straight line, a point adding process is required. And comparing the distances of the insertion points, and selecting the point with the minimum distance value as the distance from the point to the straight line.

The system comprises a second judging module 44, and the distance from the cutting point to the cutting line can be obtained without complex calculation, so that the system is more convenient and faster.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.

Claims

1. A CAD edge area detection method is characterized by comprising the following steps:

s1, establishing a tree model based on a square in the cutting area;

the step S1 specifically includes:

establishing a square model in the cutting area;

judging whether the preset layer square model is divided or not, if so, stopping dividing; otherwise, continuing to divide the square model;

s2, inserting the cutting points into the tree model;

the step S2 specifically includes:

acquiring coordinates of the cutting points;

inserting the cutting points into the region where the preset layer square model belongs;

2. The CAD edge area detection method according to claim 1, further comprising the steps of:

3. The CAD edge area detection method according to claim 2, wherein the step S4 specifically includes:

adding an insertion point on the cutting line according to a preset width;

4. A CAD edge region detection system, comprising:

the insertion module includes:

the obtaining unit is used for obtaining the coordinates of the cutting points;

the determining unit is used for inserting the cutting point into the region to which the preset layer square model belongs;

the first judgment module is used for judging whether the distance value between the cutting point and a cut point within a preset distance in the tree-shaped model is smaller than a critical value or not, and if so, judging the cutting point to be a critical area;

wherein the modeling module further comprises:

the building unit is used for building a square model in the cutting area;

5. The CAD edge region detection system of claim 4, further comprising:

6. The CAD edge area detection system of claim 5, wherein the second determination module comprises: