A crystal plasticity finite element model was developed for the drawing deformation of pure copper micro wire,based on rate-dependent crystal plasticity theory.The impact of wire diameter compression ratio on the micr...A crystal plasticity finite element model was developed for the drawing deformation of pure copper micro wire,based on rate-dependent crystal plasticity theory.The impact of wire diameter compression ratio on the micro-mechanical deformation behavior during the wire drawing process was investigated.Results indicate that the internal deformation and slip of the drawn wire are unevenly distributed,forming distinct slip and non-slip zones.Additionally,horizontal strain concentration bands develop within the drawn wire.As the wire diameter compression ratio increases,the strength of the slip systems and the extent of slip zones inside the deformation zone also increase.However,the fluctuating stress state,induced by contact pressure and frictional stress,results in a rough and uneven wire surface and diminishes the stability of the drawing process.展开更多
In this study,a numerical analysis was conducted on the ductile fracture of a 2-mm diameter Mg-1Zn-0.5Mn-0.5Sr-0.1Ca alloy wire during drawing.The hexagonally close-packed crystal structure of Mg alloys causes asymmet...In this study,a numerical analysis was conducted on the ductile fracture of a 2-mm diameter Mg-1Zn-0.5Mn-0.5Sr-0.1Ca alloy wire during drawing.The hexagonally close-packed crystal structure of Mg alloys causes asymmetric fracture behavior,especially in the compression region.The aim of this study is to develop a comprehensive damage model for Mg alloy wire that accurately predicts ductile fracture,with a focus on the compression region.A novel experimental method was introduced to measure the ductile fracture of Mg alloy wires under different stress states.The wire drawing process was simulated using the Generalized Incremental Stress-State dependent damage(GISSMO)Model and the Semi-Analytical Model for Polymers(SAMP)model.The damage model's prediction and the experimental results were found to be in excellent agreement,especially in determining crack initiation.Computational analysis established a safe zone diagram for die angle and reduction ratio,and experimental validation confirmed the feasibility of this approach.The proposed damage model can provide a practical and reliable analysis for optimizing the drawing process of Mg alloy wire.展开更多
The inherent teaching approach can no longer meet the demands of society.In this paper,current issues within the teaching landscape of architectural engineering technology in higher vocational colleges as well as the ...The inherent teaching approach can no longer meet the demands of society.In this paper,current issues within the teaching landscape of architectural engineering technology in higher vocational colleges as well as the policies and teaching demands that formed the basis of this model were analyzed.The study shows the importance of the implementation of the teaching model“promoting teaching and learning through competitions.”This model puts emphasis on the curriculum and teaching resources,while also integrating the teaching process and evaluation with competition.These efforts aim to drive education reform in order to better align with the objectives of vocational education personnel training,while also acting as a reference for similar courses.展开更多
An automated method based on the curve chain was proposed for dimensioning of engineering drawings for the mechanical products.According to the internal relation between the features of 3D model feature and elements o...An automated method based on the curve chain was proposed for dimensioning of engineering drawings for the mechanical products.According to the internal relation between the features of 3D model feature and elements of 2D drawing,the curve chain was established to reflect the geometric topological structure between the elements.It divides the dimensions into the absolute dimensions within the cure chain and the relative dimensions between the curve chains.The parallel and lengthy relationship between the drawing elements of the constructed X and Y parallel matrix was solved to remove redundant elements in the curve chain and labeled the absolute dimensions of the remaining valid elements.The average minimum weight coefficient was introduced to judge the dependence on the relative dimensions between curve chains.Through the analysis of the overlap between the circular rectangular areas,including all the absolute dimensions of the curve chains,overlapping curve chains were merged,and their dimensions were rearranged to avoid the cross interference between them.The method was seamlessly integrated into the drafting module of product design software NX,and it developed an automated dimensioning system.The examples show that the system has excellent interactivity and robustness in the dimensioning of product engineering drawings.The dimension information is complete,accurate and reliable.展开更多
Although line drawings consist of only line segments on a plane, they convey much information about the three-dimensional object structures. For a computer interpreting line drawings, some intelligent mechanism is req...Although line drawings consist of only line segments on a plane, they convey much information about the three-dimensional object structures. For a computer interpreting line drawings, some intelligent mechanism is required to extract three-dimensional information from the two-dimensional line drawings. In this paper, a new labeling theory and method are proposed for the two-dimensional line drawing with hidden-part-draw of a three-dimensional planar object with trihedral vertices. Some rules for labeling line drawing are established. There are 24 kinds of possible junctions for line drawing with hidden-part-draw, in which there are 8 possible Y and 16 W junctions. The three problems are solved that Sugihara's line drawing labeling technique exists. By analyzing the projections of the holes in manifold planar object, we have put forward a labeling method for the line drawing. Our labeling theory and method can discriminate between correct and incorrect hidden-part-draw natural line drawings. The hidden-part-draw natural line drawings can be labeled correctly by our labeling theory and method, whereas the labeling theory of Sugihara can only label the hidden-part-draw unnatural line drawings in which some visible lines must be drawn as hidden lines, and some invisible lines must be drawn as continuous lines.展开更多
It is a research subject in computer vision to 3D reconstruction of an object represented by a single 2D line drawing. Previous works on 3D reconstruction from 2D line drawings focus on objects with lines, plane, view...It is a research subject in computer vision to 3D reconstruction of an object represented by a single 2D line drawing. Previous works on 3D reconstruction from 2D line drawings focus on objects with lines, plane, view, and so on. This paper mainly studies the 3D reconstruction from 2D line drawings. Besides, a new approach is proposed: it is that for the research of the point coordinates of 2D line drawings, so as to achieve the object reconstruction by the reconstruction of point coordinates. The reconstruction process includes: (1) the collection of point coordinates (X,Y) of 2D line drawings; (2) the derivation of mathematical formula about the reconstruction of the point of 2D line drawings, and calculating the corresponding point of the 3D coordinates; (3) the regeneration of 3D graphics with 3D points; (4) analyze error by the proportional of parallel of axonometric projection, in order to prove the accuracy of the method.展开更多
In order to provide the model point accuracy of ±2 mm,an extra high accuracy industrial control net with four surveying piers with accuracy ±0.1 mm was set up around the model.Tens of orientation marks have ...In order to provide the model point accuracy of ±2 mm,an extra high accuracy industrial control net with four surveying piers with accuracy ±0.1 mm was set up around the model.Tens of orientation marks have been placed on the different parts and measured with accuracy ±0.2 mm from the above_mentioned piers.The main four stereopairs taken with the P31 camera around the model are simultaneously processed on the BC2 analytical plotter.The accuracy of absolute orientation is better than ±0.9 mm.Finally,about 300 sections construction drawings have been directly offered,and the close_range photogrammetric data has been used for the design and construction of the statue.展开更多
At present,iron and steel enterprises mainly use“after spot test ward”to control final product quality.However,it is impossible to realize on-line quality predetermining for all products by this traditional approach...At present,iron and steel enterprises mainly use“after spot test ward”to control final product quality.However,it is impossible to realize on-line quality predetermining for all products by this traditional approach,hence claims and returns often occur,resulting in major eco-nomic losses of enterprises.In order to realize the on-line quality predetermining for steel products during manufacturing process,the predic-tion models of mechanical properties based on deep learning have been proposed in this work.First,the mechanical properties of deep drawing steels were predicted by using LSTM(long short team memory),GRU(gated recurrent unit)network,and GPR(Gaussian process regression)model,and prediction accuracy and learning efficiency for different models were also discussed.Then,on-line re-learning methods for transfer learning models and model parameters were proposed.The experimental results show that not only the prediction accuracy of optimized trans-fer learning models has been improved,but also predetermining time was shortened to meet real time requirements of on-line property prede-termining.The industrial production data of interstitial-free(IF)steel was used to demonstrate that R2 value of GRU model in training stage reaches more than 0.99,and R2 value in testing stage is more than 0.96.展开更多
AIM: To evaluate the efficacy of drawings as a projective measure of pain and distress in children undergoing dental extractions.METHODS: Children in the age range of 4-13 years with existence of untreatable caries or...AIM: To evaluate the efficacy of drawings as a projective measure of pain and distress in children undergoing dental extractions.METHODS: Children in the age range of 4-13 years with existence of untreatable caries or over-retained primary teeth, indicated for extractions were included. Pain was assessed using one behavioral, faces, legs, activity, cry and consolability(FLACC) scale; and a self report measure; faces pain scale-revised(FPS-R), at two points of time, after completion of local anesthetic administration and after extraction. The general behavior of children was assessed with Wright's modification of Frankl rating scale. At the end of the session, children were instructed to represent, themselves along with the dentist and their experiences of the dental treatment through drawing. The drawings were scored utilizing Child drawing: Hospital scale(CD: H) manual and correlated with FLACC, FPS-R and Frankl using Pearson correlation test.RESULTS: A positive correlation, though statistically not significant, was observed between CD: H scores and all other considered parameters(Frankl, FPS-R and FLACC) in the present study.CONCLUSION: Drawings could not act as surrogate measure of child's pain; however, they acted as a narrative of his/her experiences and reflection of inner emotions. Hence, drawings can be used as an additional dental armamentarium.展开更多
A software for the management of computer aided design(CAD) drawings was developed. It can be used to classify and register information including geometric features of the drawings, and to search appropriate referen...A software for the management of computer aided design(CAD) drawings was developed. It can be used to classify and register information including geometric features of the drawings, and to search appropriate reference drawings matching the given conditions of a new design. The thumbnails of the drawings can be displayed in an order of preference and can be used to zoom and access the PDF file or CAD data of a selected drawing. The thumbnails and the data structure are two key elements of the software.展开更多
The Winter Olympic Games from European children’s perspectives.WITH only 100 days left to the opening ceremony of the Beijing 2022 Olympic and Paralympic Winter Games(Beijing 2022),an exhibition of hand-written poste...The Winter Olympic Games from European children’s perspectives.WITH only 100 days left to the opening ceremony of the Beijing 2022 Olympic and Paralympic Winter Games(Beijing 2022),an exhibition of hand-written posters selected from the“Draw Beijing 2022 Winter Olympics&Learn Chinese”activity kicked off online.展开更多
Taking spiral chute as example, a method of unfolded drawings and views about irregular spiral surface is introduced. The surface is undevelopable and too complicated to get its views or to draw unfolded drawings by m...Taking spiral chute as example, a method of unfolded drawings and views about irregular spiral surface is introduced. The surface is undevelopable and too complicated to get its views or to draw unfolded drawings by manual method. In this article, a series of the boundary equations of the spiral chute are derived by the movement rule of coal flow, and the solid and views of the spiral chute are generated based on redevelopment of SolidWorks. Unfolded drawing is drawn applying triangular development principle. The views and unfolded drawings not only are produced automatically, precisely and parameterized, but also involve more technological information. So it has an important significance on the irregular spiral surface's developments and processing.展开更多
Recent development and recognition methods of raster to vector conversion for engineering drawings are presented. The advantages and disadvantages of all existing models are analyzed. Some research challenges and futu...Recent development and recognition methods of raster to vector conversion for engineering drawings are presented. The advantages and disadvantages of all existing models are analyzed. Some research challenges and future directions are discussed.展开更多
An active research topic in computer vision and graphics is developing algorithms that can reconstruct the 3D surface of curved objects from line drawings. There are a number of algorithms have been dedicated to solve...An active research topic in computer vision and graphics is developing algorithms that can reconstruct the 3D surface of curved objects from line drawings. There are a number of algorithms have been dedicated to solve this problem, but they can't solve this problem when the geometric structure of a curved object becomes complex. This paper proposes a novel approach to reconstructing a complex curved 3D object from single 2D line drawings. Our approach has three steps: (1) decomposing a complex line drawing into several simpler line drawings and transforming them into polyhedron; (2) reconstructing the 3D wireframe of curved object from these simpler line drawings and generating the curved faces; (3) combining the 3D objects into the complete objects. A number of examples are given to demonstrate the ability of our approach to successfully perform reconstruction of curved objects which are more complex than previous methods.展开更多
Abstract: Hand drawings and two dimensional (2D) CAD drawings have been replaced by three dimensional (3D) CAD models in mechanical design, but some 2D drawings produced before are needed in the new design. Howev...Abstract: Hand drawings and two dimensional (2D) CAD drawings have been replaced by three dimensional (3D) CAD models in mechanical design, but some 2D drawings produced before are needed in the new design. However, the techniques and software packages for automatically converting 2D drawings into 3D-CAD models with high precision have not yet been developed due to the difficulties to verify the validity of the drawings, to decide the hidden lines and eoncavo-convex faces, and to represent free-form surfaces. In addition, it is very time consuming to manually convert a large number of 2D drawings into 3D CAD models. To address these problems, we propose an approach for converting 2D drawings into 3D-CAD models automatically.展开更多
The human vision system can reconstruct a 3D object easily from single 2D line drawings even if the hidden lines of the object are invisible. Now, there are many methods have emulated this ability, but when the hidden...The human vision system can reconstruct a 3D object easily from single 2D line drawings even if the hidden lines of the object are invisible. Now, there are many methods have emulated this ability, but when the hidden lines of the object are invisible, these methods cannot reconstruct a complete 3D object. Therefore, we put forward a new algorithm to settle this hard problem. Our approach consists of two steps: (1) infer the invisible vertices and edges to complete the line drawing, (2) propose a vertex-based optimization method to reconstruct a 3D object.展开更多
As the secondary development language of Auto CAD,Auto LISP is widely used in the standard rendering of various complex graphics.This method uses Auto LISP as a tool to select and draw three common bearings according ...As the secondary development language of Auto CAD,Auto LISP is widely used in the standard rendering of various complex graphics.This method uses Auto LISP as a tool to select and draw three common bearings according to the matched spindles.This paper describes the key steps of bearing parametric drawing and implementation process in detail.This developed program simplifies the drawing process,reduces the repetitive work in the design,and improves the efficiency of drawing.展开更多
基金the National Natural Science Foundation of China(Nos.U21A2051,52173297,52071133)the R&D Projects of Henan Academy of Sciences of China(No.220910009)+2 种基金the Key R&D and Promotion Projects of Henan Province of China(No.212102210441)the Joint Fund of Henan Science and Technology R&D Plan of China(No.222103810037)the Zhongyuan Scholar Workstation Funded Project of China(No.214400510028).
文摘A crystal plasticity finite element model was developed for the drawing deformation of pure copper micro wire,based on rate-dependent crystal plasticity theory.The impact of wire diameter compression ratio on the micro-mechanical deformation behavior during the wire drawing process was investigated.Results indicate that the internal deformation and slip of the drawn wire are unevenly distributed,forming distinct slip and non-slip zones.Additionally,horizontal strain concentration bands develop within the drawn wire.As the wire diameter compression ratio increases,the strength of the slip systems and the extent of slip zones inside the deformation zone also increase.However,the fluctuating stress state,induced by contact pressure and frictional stress,results in a rough and uneven wire surface and diminishes the stability of the drawing process.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(Nos.2020R1A2C2010986,2022M3H4A1A04085301)。
文摘In this study,a numerical analysis was conducted on the ductile fracture of a 2-mm diameter Mg-1Zn-0.5Mn-0.5Sr-0.1Ca alloy wire during drawing.The hexagonally close-packed crystal structure of Mg alloys causes asymmetric fracture behavior,especially in the compression region.The aim of this study is to develop a comprehensive damage model for Mg alloy wire that accurately predicts ductile fracture,with a focus on the compression region.A novel experimental method was introduced to measure the ductile fracture of Mg alloy wires under different stress states.The wire drawing process was simulated using the Generalized Incremental Stress-State dependent damage(GISSMO)Model and the Semi-Analytical Model for Polymers(SAMP)model.The damage model's prediction and the experimental results were found to be in excellent agreement,especially in determining crack initiation.Computational analysis established a safe zone diagram for die angle and reduction ratio,and experimental validation confirmed the feasibility of this approach.The proposed damage model can provide a practical and reliable analysis for optimizing the drawing process of Mg alloy wire.
文摘The inherent teaching approach can no longer meet the demands of society.In this paper,current issues within the teaching landscape of architectural engineering technology in higher vocational colleges as well as the policies and teaching demands that formed the basis of this model were analyzed.The study shows the importance of the implementation of the teaching model“promoting teaching and learning through competitions.”This model puts emphasis on the curriculum and teaching resources,while also integrating the teaching process and evaluation with competition.These efforts aim to drive education reform in order to better align with the objectives of vocational education personnel training,while also acting as a reference for similar courses.
基金This work is supported by the Science and Technology Planning Project of Ronggui(grant number RGJF(2017)27H-8).
文摘An automated method based on the curve chain was proposed for dimensioning of engineering drawings for the mechanical products.According to the internal relation between the features of 3D model feature and elements of 2D drawing,the curve chain was established to reflect the geometric topological structure between the elements.It divides the dimensions into the absolute dimensions within the cure chain and the relative dimensions between the curve chains.The parallel and lengthy relationship between the drawing elements of the constructed X and Y parallel matrix was solved to remove redundant elements in the curve chain and labeled the absolute dimensions of the remaining valid elements.The average minimum weight coefficient was introduced to judge the dependence on the relative dimensions between curve chains.Through the analysis of the overlap between the circular rectangular areas,including all the absolute dimensions of the curve chains,overlapping curve chains were merged,and their dimensions were rearranged to avoid the cross interference between them.The method was seamlessly integrated into the drafting module of product design software NX,and it developed an automated dimensioning system.The examples show that the system has excellent interactivity and robustness in the dimensioning of product engineering drawings.The dimension information is complete,accurate and reliable.
文摘Although line drawings consist of only line segments on a plane, they convey much information about the three-dimensional object structures. For a computer interpreting line drawings, some intelligent mechanism is required to extract three-dimensional information from the two-dimensional line drawings. In this paper, a new labeling theory and method are proposed for the two-dimensional line drawing with hidden-part-draw of a three-dimensional planar object with trihedral vertices. Some rules for labeling line drawing are established. There are 24 kinds of possible junctions for line drawing with hidden-part-draw, in which there are 8 possible Y and 16 W junctions. The three problems are solved that Sugihara's line drawing labeling technique exists. By analyzing the projections of the holes in manifold planar object, we have put forward a labeling method for the line drawing. Our labeling theory and method can discriminate between correct and incorrect hidden-part-draw natural line drawings. The hidden-part-draw natural line drawings can be labeled correctly by our labeling theory and method, whereas the labeling theory of Sugihara can only label the hidden-part-draw unnatural line drawings in which some visible lines must be drawn as hidden lines, and some invisible lines must be drawn as continuous lines.
文摘It is a research subject in computer vision to 3D reconstruction of an object represented by a single 2D line drawing. Previous works on 3D reconstruction from 2D line drawings focus on objects with lines, plane, view, and so on. This paper mainly studies the 3D reconstruction from 2D line drawings. Besides, a new approach is proposed: it is that for the research of the point coordinates of 2D line drawings, so as to achieve the object reconstruction by the reconstruction of point coordinates. The reconstruction process includes: (1) the collection of point coordinates (X,Y) of 2D line drawings; (2) the derivation of mathematical formula about the reconstruction of the point of 2D line drawings, and calculating the corresponding point of the 3D coordinates; (3) the regeneration of 3D graphics with 3D points; (4) analyze error by the proportional of parallel of axonometric projection, in order to prove the accuracy of the method.
文摘In order to provide the model point accuracy of ±2 mm,an extra high accuracy industrial control net with four surveying piers with accuracy ±0.1 mm was set up around the model.Tens of orientation marks have been placed on the different parts and measured with accuracy ±0.2 mm from the above_mentioned piers.The main four stereopairs taken with the P31 camera around the model are simultaneously processed on the BC2 analytical plotter.The accuracy of absolute orientation is better than ±0.9 mm.Finally,about 300 sections construction drawings have been directly offered,and the close_range photogrammetric data has been used for the design and construction of the statue.
基金financially supported by the National Natural Science Foundation of China (No. 52175284)the State Key Lab of Advanced Metals and Materials in University of Science and Technology Beijing (No. 2021ZD08)
文摘At present,iron and steel enterprises mainly use“after spot test ward”to control final product quality.However,it is impossible to realize on-line quality predetermining for all products by this traditional approach,hence claims and returns often occur,resulting in major eco-nomic losses of enterprises.In order to realize the on-line quality predetermining for steel products during manufacturing process,the predic-tion models of mechanical properties based on deep learning have been proposed in this work.First,the mechanical properties of deep drawing steels were predicted by using LSTM(long short team memory),GRU(gated recurrent unit)network,and GPR(Gaussian process regression)model,and prediction accuracy and learning efficiency for different models were also discussed.Then,on-line re-learning methods for transfer learning models and model parameters were proposed.The experimental results show that not only the prediction accuracy of optimized trans-fer learning models has been improved,but also predetermining time was shortened to meet real time requirements of on-line property prede-termining.The industrial production data of interstitial-free(IF)steel was used to demonstrate that R2 value of GRU model in training stage reaches more than 0.99,and R2 value in testing stage is more than 0.96.
文摘AIM: To evaluate the efficacy of drawings as a projective measure of pain and distress in children undergoing dental extractions.METHODS: Children in the age range of 4-13 years with existence of untreatable caries or over-retained primary teeth, indicated for extractions were included. Pain was assessed using one behavioral, faces, legs, activity, cry and consolability(FLACC) scale; and a self report measure; faces pain scale-revised(FPS-R), at two points of time, after completion of local anesthetic administration and after extraction. The general behavior of children was assessed with Wright's modification of Frankl rating scale. At the end of the session, children were instructed to represent, themselves along with the dentist and their experiences of the dental treatment through drawing. The drawings were scored utilizing Child drawing: Hospital scale(CD: H) manual and correlated with FLACC, FPS-R and Frankl using Pearson correlation test.RESULTS: A positive correlation, though statistically not significant, was observed between CD: H scores and all other considered parameters(Frankl, FPS-R and FLACC) in the present study.CONCLUSION: Drawings could not act as surrogate measure of child's pain; however, they acted as a narrative of his/her experiences and reflection of inner emotions. Hence, drawings can be used as an additional dental armamentarium.
文摘A software for the management of computer aided design(CAD) drawings was developed. It can be used to classify and register information including geometric features of the drawings, and to search appropriate reference drawings matching the given conditions of a new design. The thumbnails of the drawings can be displayed in an order of preference and can be used to zoom and access the PDF file or CAD data of a selected drawing. The thumbnails and the data structure are two key elements of the software.
文摘The Winter Olympic Games from European children’s perspectives.WITH only 100 days left to the opening ceremony of the Beijing 2022 Olympic and Paralympic Winter Games(Beijing 2022),an exhibition of hand-written posters selected from the“Draw Beijing 2022 Winter Olympics&Learn Chinese”activity kicked off online.
基金Supported by the National Natural Science Foundation,China (No.51005237)the Postdoctoral Science Foundation,China (No.20100471407)
文摘Taking spiral chute as example, a method of unfolded drawings and views about irregular spiral surface is introduced. The surface is undevelopable and too complicated to get its views or to draw unfolded drawings by manual method. In this article, a series of the boundary equations of the spiral chute are derived by the movement rule of coal flow, and the solid and views of the spiral chute are generated based on redevelopment of SolidWorks. Unfolded drawing is drawn applying triangular development principle. The views and unfolded drawings not only are produced automatically, precisely and parameterized, but also involve more technological information. So it has an important significance on the irregular spiral surface's developments and processing.
文摘Recent development and recognition methods of raster to vector conversion for engineering drawings are presented. The advantages and disadvantages of all existing models are analyzed. Some research challenges and future directions are discussed.
文摘An active research topic in computer vision and graphics is developing algorithms that can reconstruct the 3D surface of curved objects from line drawings. There are a number of algorithms have been dedicated to solve this problem, but they can't solve this problem when the geometric structure of a curved object becomes complex. This paper proposes a novel approach to reconstructing a complex curved 3D object from single 2D line drawings. Our approach has three steps: (1) decomposing a complex line drawing into several simpler line drawings and transforming them into polyhedron; (2) reconstructing the 3D wireframe of curved object from these simpler line drawings and generating the curved faces; (3) combining the 3D objects into the complete objects. A number of examples are given to demonstrate the ability of our approach to successfully perform reconstruction of curved objects which are more complex than previous methods.
文摘Abstract: Hand drawings and two dimensional (2D) CAD drawings have been replaced by three dimensional (3D) CAD models in mechanical design, but some 2D drawings produced before are needed in the new design. However, the techniques and software packages for automatically converting 2D drawings into 3D-CAD models with high precision have not yet been developed due to the difficulties to verify the validity of the drawings, to decide the hidden lines and eoncavo-convex faces, and to represent free-form surfaces. In addition, it is very time consuming to manually convert a large number of 2D drawings into 3D CAD models. To address these problems, we propose an approach for converting 2D drawings into 3D-CAD models automatically.
文摘The human vision system can reconstruct a 3D object easily from single 2D line drawings even if the hidden lines of the object are invisible. Now, there are many methods have emulated this ability, but when the hidden lines of the object are invisible, these methods cannot reconstruct a complete 3D object. Therefore, we put forward a new algorithm to settle this hard problem. Our approach consists of two steps: (1) infer the invisible vertices and edges to complete the line drawing, (2) propose a vertex-based optimization method to reconstruct a 3D object.
文摘As the secondary development language of Auto CAD,Auto LISP is widely used in the standard rendering of various complex graphics.This method uses Auto LISP as a tool to select and draw three common bearings according to the matched spindles.This paper describes the key steps of bearing parametric drawing and implementation process in detail.This developed program simplifies the drawing process,reduces the repetitive work in the design,and improves the efficiency of drawing.