基于跖跗围参数的鞋楦曲面重构

针对面向合脚性、舒适性的鞋楦个性化设计中的曲面重构问题,提出并实 现了一种基于鞋楦跖跗围截面变换技术的鞋楦曲面参数化重构方法。通过对鞋楦跖跗截面围 长和高度的控制,将跖、跗围的截面曲线变换到个性化设计所需求效果;基于三次样条插值 函数构造局部、整体两类扩散函数,实现两种将两围截面变换效果扩散到整个鞋楦曲面的方 式。此算法不仅可以准确地满足鞋楦围长约束要求,且保持了曲面光顺性。所提出的重构过 程在Matlab 平台上可以实现可视化交互设计,界面具有操作简单方便的特点。     

鞋楦的数字化设计与软件开发

以逆向工程技术和软件开发为基础,对鞋楦的数字化设计进行研究：结合传统鞋楦制作技术,采用基于点云的散乱结构的均匀网格方法,对扫描获取的鞋楦点云数据进行精简;采用最小二乘逼近的方法,将处理后的点云数据拟合成NURBS曲线,进而采用蒙皮算法得到鞋楦曲面。开发了鞋楦数字化设计专用模块,为以后根据脚型对标准鞋楦进行个性化修改的开发奠定了基础。     

Abstracting Service

The purpose of this study was to determine whether there were any significant differences in the morphology of the feet of children living on two different continents. The shape and dimensions of the feet of 86 preschool and 419 primary school children from Australia, matched to the same number of German children for age, gender, height and BMI, were compared. The German children display significantly longer and flatter feet relative to their Australian counterparts, whereas the Australian children reveal a significantly smaller ball angle, implying that the forefoot of the Australian children is squarer in shape. These findings imply that footwear must be designed to cater to the unique foot dimensions of children in different continents to ensure that shoe shape matches foot shape. Most footwear companies do not vary the dimensions of their shoe lasts to accommodate intercontinental differences in foot morphology based on racial and/or environmental factors. The results of this study will have immediate implications for the design of comfortable footwear suitable for the developing feet of children.     

Do the feet of German and Australian children differ in structure? Implications for children's shoe design

The purpose of this study was to determine whether there were any significant differences in the morphology of the feet of children living on two different continents. The shape and dimensions of the feet of 86 preschool and 419 primary school children from Australia, matched to the same number of German children for age, gender, height and BMI, were compared. The German children display significantly longer and flatter feet relative to their Australian counterparts, whereas the Australian children reveal a significantly smaller ball angle, implying that the forefoot of the Australian children is squarer in shape. These findings imply that footwear must be designed to cater to the unique foot dimensions of children in different continents to ensure that shoe shape matches foot shape. Most footwear companies do not vary the dimensions of their shoe lasts to accommodate intercontinental differences in foot morphology based on racial and/or environmental factors. The results of this study will have immediate implications for the design of comfortable footwear suitable for the developing feet of children.     

Dimensional differences for evaluating the quality of footwear fit

Very few standards exist for fitting products to people. Footwear is a noteworthy example. This study is an attempt to evaluate the quality of footwear fit using two-dimensional foot outlines. Twenty Hong Kong Chinese students participated in an experiment that involved three pairs of dress shoes and one pair of athletic shoes. The participants' feet were scanned using a commercial laser scanner, and each participant wore and rated the fit of each region of each shoe. The shoe lasts were also scanned and were used to match the foot scans with the last scans. The ANOVA showed significant (p < 0.05) differences among the four pairs of shoes for the overall, fore-foot and rear-foot fit ratings. There were no significant differences among shoes for mid-foot fit rating. These perceived differences were further analysed after matching the 2D outlines of both last and feet. The point-wise dimensional difference between foot and shoe outlines were computed and analysed after normalizing with foot perimeter. The dimensional difference (DD) plots along the foot perimeter showed that fore-foot fit was strongly correlated (R(2) > 0.8) with two of the minimums in the DD-plot while mid-foot fit was strongly correlated (R(2) > 0.9) with the dimensional difference around the arch region and a point on the lateral side of the foot. The DD-plots allow the designer to determine the critical locations that may affect footwear fit in addition to quantifying the nature of misfit so that design changes to shape and material may be possible.     

Development of new shoe sizing system for women based on regression analysis of foot shapes

This study aims to demonstrate a new method of developing a shoe sizing system with a standard fitting for each size for Bangladeshi women based on foot measurements. In this study, bivariate correlation analysis was carried out to determine key foot dimensions of 976 women aged 20 to 60. Simple linear regression analyses of key parameters against foot length (FL) were conducted, and the regression equations assisted in determining grading value and size-fit combinations. Nine sizes with three fittings (narrow, standard, and wide) each were generated where the grading values were 6 mm, 5 mm, 2 mm, and 4 mm for FL, joint girth (JG), joint width (JW), and arch length (AL), respectively. Cross-tabulation analysis verified the sizing system with a coverage rate 94.98% of JG, 88.02% of JW, and 98.77% of AL, where standard fittings covered the maximum number of participants. This study could benefit women in choosing accurate shoe sizes for their feet to ensure proper shoe fitting.Relevance to industryThe proposed new shoe sizing system could assist the footwear industries in manufacturing women's shoes in different sizes with appropriate sizing and grading values, which will provide better fitting than existing systems. In addition, industries could produce shoes with a smaller number of size-fit combinations to accommodate most women's feet.     

Dimensional differences for evaluating the quality of footwear fit

Very few standards exist for fitting products to people. Footwear is a noteworthy example. This study is an attempt to evaluate the quality of footwear fit using two-dimensional foot outlines. Twenty Hong Kong Chinese students participated in an experiment that involved three pairs of dress shoes and one pair of athletic shoes. The participants' feet were scanned using a commercial laser scanner, and each participant wore and rated the fit of each region of each shoe. The shoe lasts were also scanned and were used to match the foot scans with the last scans. The ANOVA showed significant (p?<?0.05) differences among the four pairs of shoes for the overall, fore-foot and rear-foot fit ratings. There were no significant differences among shoes for mid-foot fit rating. These perceived differences were further analysed after matching the 2D outlines of both last and feet. The point-wise dimensional difference between foot and shoe outlines were computed and analysed after normalizing with foot perimeter. The dimensional difference (DD) plots along the foot perimeter showed that fore-foot fit was strongly correlated (R ²?>?0.8) with two of the minimums in the DD-plot while mid-foot fit was strongly correlated (R ²?>?0.9) with the dimensional difference around the arch region and a point on the lateral side of the foot. The DD-plots allow the designer to determine the critical locations that may affect footwear fit in addition to quantifying the nature of misfit so that design changes to shape and material may be possible.     

Taiwanese adult foot shape classification using 3D scanning data

This study classifies the foot shapes of Taiwanese using 3D foot scanning data from 2000 males and 1000 females. Nine foot dimensions relative to foot length and absolute measures in the common foot length categories were applied to compare the gender differences. Using foot breadth in % foot length (% FL), ball of foot length in % FL and arch height in % FL as feature parameters, three foot shape types for males and females can be classified. Significant gender differences were found in seven of the nine foot dimensions. Females had greater ball of foot length than males (0.2% FL). When comparing feet of the same foot length, males had greater breadth, girth and height dimensions than females, except for toe height. In addition, ethnic differences in foot shape were also observed. The findings can provide very useful information for building gender-specific shoe lasts and designing footwear insoles.     

Sex-related differences in foot shape of adult Caucasians--a follow-up study focusing on long and short feet

The study's purpose was to substantiate findings on sex-related differences in foot morphology focusing on fringe sizes. Altogether, 287 Caucasian adults with long or short feet were scanned. Data were analysed together with data from 847 subjects from a previous study with comparable inclusion criteria and anthropometric data by: (1)comparing absolute measures within 237-277 mm foot length (FL); (2) comparing averaged measures across sizes in % of foot length for 203-323 mm FL; (3) reclassifying the additional subjects into a previously defined foot type classification. Male feet were wider and higher for the same FL. Averaged across sizes, no relevant differences between sexes were found for widths and heights. Slender or flat-pointed foot types were more common in longer feet, shorter feet tended to be bigger. Definitions for 'long' and 'short' are sex-related with an offset of three shoe sizes (EU). Results of this follow-up study on long and short feet can substantiate previous findings mainly described for the most common sizes. STATEMENT OF RELEVANCE: Improper footwear can cause pain and injury and proper fit is a major criterion for shoe buyers. Knowledge about sex-related differences in foot shape is important for shoe design. This study supplements the field of knowledge for very small and large feet.     

鞋楦CAD中的鞋楦建模与局部修改技术

讨论了CAD中的鞋楦建模方法，针对鞋楦曲面的不规则性，提出一种离散造型方法并给出一种计算鞋楦围度的逼近算法，同时，提出一个斜率定义，进而给出一个比较实用的基于斜率变化的自适应楦面局部修改算法（简称SAD算法），最后给出一个实例。     

Sex-related differences in foot shape of adult Caucasians – a follow-up study focusing on long and short feet

The study's purpose was to substantiate findings on sex-related differences in foot morphology focusing on fringe sizes. Altogether, 287 Caucasian adults with long or short feet were scanned. Data were analysed together with data from 847 subjects from a previous study with comparable inclusion criteria and anthropometric data by: (1)comparing absolute measures within 237–277 mm foot length (FL); (2) comparing averaged measures across sizes in % of foot length for 203–323mm FL; (3) reclassifying the additional subjects into a previously defined foot type classification. Male feet were wider and higher for the same FL. Averaged across sizes, no relevant differences between sexes were found for widths and heights. Slender or flat-pointed foot types were more common in longer feet, shorter feet tended to be bigger. Definitions for ‘long’ and ‘short’ are sex-related with an offset of three shoe sizes (EU). Results of this follow-up study on long and short feet can substantiate previous findings mainly described for the most common sizes.

Statement of Relevance: Improper footwear can cause pain and injury and proper fit is a major criterion for shoe buyers. Knowledge about sex-related differences in foot shape is important for shoe design. This study supplements the field of knowledge for very small and large feet.     

Foot flare and foot axis

Most commercial footwear is designed and manufactured on a curved last, although the amount of curvature of the last and the turning point of the last centerline have not been formally determined. In this study, we used principal component analysis to determine the foot axis so that lasts that match feet can be produced, resulting in a good fit. In evaluating 50 Hong Kong Chinese participants, we found that the center of the foot is located at approximately 52% of the foot length measuring from the back of the foot (SD = 0.65%) and that Hong Kong participants have a mean inflare (inward curvature) of 3.2 degrees. The foot center and inflare measures will help determine the fit between footwear and feet. Applications of this research include the ability to incorporate foot flare into the design and manufacture of footwear.     

Non-uniform deformation of an STL model satisfying error criteria

In this research, a method is presented for generating a deformed model satisfying given error criteria from an STL model in a triangular-mesh representation suitable for rapid prototyping (RP) processes. A deformed model is a non-uniformly modified shape from a base STL model. In developing a family product with various sizes such as a shoe, sometimes prototypes for all sizes should be made using an RP machine. Although an STL model is generated from a solid model, it is well known that creating a non-uniformly modified solid model from a base solid model is very difficult. Generally there are some gaps between surfaces after modification, and stitching the gaps is very difficult. To solve this problem, the authors explored the possibility of generating a deformed STL model directly from a base STL model. This research includes a data structure for modifying the STL model, checking the error of a modified edge compared with the exact non-uniformly scaled curve, checking the error of a modified facet compared with the exact non-uniformly scaled surface, and splitting a facet with an error greater than the allowable tolerance. Using the results of this research, the difficult work of creating solid models to build non-uniformly deformed STL models could be avoided.     

A systematic approach to determining metamodel scope for risk-based optimization and its application to water distribution system design

Metamodels have proven be very useful when it comes to reducing the computational requirements of Evolutionary Algorithm-based optimization by acting as quick-solving surrogates for slow-solving fitness functions. The relationship between metamodel scope and objective function varies between applications, that is, in some cases the metamodel acts as a surrogate for the whole fitness function, whereas in other cases it replaces only a component of the fitness function. This paper presents a formalized qualitative process to evaluate a fitness function to determine the most suitable metamodel scope so as to increase the likelihood of calibrating a high-fidelity metamodel and hence obtain good optimization results in a reasonable amount of time. The process is applied to the risk-based optimization of water distribution systems; a very computationally-intensive problem for real-world systems. The process is validated with a simple case study (modified New York Tunnels) and the power of metamodelling is demonstrated on a real-world case study (Pacific City) with a computational speed-up of several orders of magnitude.     

基于点的鞋楦CAD/CAM技术

提出了实用的基于点的鞋楦CAD／CAM技术,给出了基于点的鞋楦几何模型定义,由经过规则化处理的鞋楦表面数据点集表示鞋楦模型;在此基础上研究了鞋楦CAD方法,通过对点集的操作完成鞋楦设计;实现了鞋楦数控编程,建立刀具模型并给出刀位点计算的详细过程．该技术已经成功地用于鞋楦CAD／CAM系统的开发,并用于实际生产,完成鞋楦的高效设计与制造。     

Foot deformation during walking: differences between static and dynamic 3D foot morphology in developing feet

The complex functions of feet require a specific composition, which is progressively achieved by developmental processes. This development should take place without being affected by footwear. The aim of this study is to evaluate differences between static and dynamic foot morphology in developing feet. Feet of 2554 participants (6–16 years) were recorded using a new scanner system (DynaScan4D). Each foot was recorded in static half and full weight-bearing and during walking. Several foot measures corresponding to those used in last construction were calculated. The differences were identified by one-way ANOVA and paired Student's t-test. Static and dynamic values of each foot measure must be considered to improve the fit of footwear. In particular, footwear must account for the increase of forefoot width and the decrease of midfoot girth. Furthermore, the toe box should have a more rounded shape. The findings are important for the construction of footwear for developing feet.     

A new approach to children's footwear based on foot type classification

Current shoe designs do not allow for the comprehensive 3-D foot shape, which means they are unable to reproduce the wide variability in foot morphology. Therefore, the purpose of this study was to capture these variations of children's feet by classifying them into groups (types) and thereby provide a basis for their implementation in the design of children's shoes. The feet of 2867 German children were measured using a 3-D foot scanner. Cluster analysis was then applied to classify the feet into three different foot types. The characteristics of these foot types differ regarding their volume and forefoot shape both within and between shoe sizes. This new approach is in clear contrast to previous systems, since it captures the variability of foot morphology in a more comprehensive way by using a foot typing system and therefore paves the way for the unimpaired development of children's feet. Previous shoe systems do not allow for the wide variations in foot morphology. A new approach was developed regarding different morphological foot types based on 3-D measurements relevant in shoe construction. This can be directly applied to create specific designs for children's shoes.     

Model based foot shape classification using 2D foot outlines

This study introduces a novel technique to identify foot outline characteristics and to classify feet into groups using turning functions and clustering techniques so that shape can complement anthropometry in producing good fitting shoes. The digital 3D foot scans, obtained from 50 Hong Kong Chinese subjects (25 males and 25 females) were processed to generate the foot outlines at heights of 2 mm and 40 mm. The outlines were represented as turning functions and the similarity among shapes was determined using average linkage clustering. The results show that there are two distinct shape groups for the 40 mm foot outlines on both medial and lateral sides of the foot. The presence (46%) or absence (54%) of a medial bulge characterizes the medial side, while the two shape groups on the lateral side are mainly due to the lateral concavity in the mid-foot region. The group with a lateral concavity consists of more females (68%) and thus lateral side of foot outline appears to be gender related. Furthermore, the medial and lateral side clusters are not related to each other. The medial side shape from the 2 mm foot outline is a good indicator of fallen arches. Based on the analyses, four types of feet were identified: feet with (1) lateral concavity and a medial bulge, (2) a medial bulge and no lateral concavity, (3) lateral concavity and no medial bulge and (4) lateral concavity and a medial bulge. These shape differences can be useful in the design of shoe lasts and in the manufacture of compatible footwear so that trial and error fitting can be minimized.     

Ethnic differences in forefoot shape and the determination of shoe comfort

The kinanthropometric aspects of comfort of fit of sport shoes has not been subjected to any great scrutiny. It is suggested that comfort of fit is largely determined by the match of foot shape to shoe shape and consequently there is a need for normative data that describe foot shape, dimension and proportion for discrete populations. A study of 708 second generation Caucasian N. American (NA) and 513 Japanese and Korean (JK) male subjects was conducted to determine normative data with respect to forefoot shape and dimension. A series of 2 height, 7 length, 1 breadth and 1 girth measures of the right foot bearing full body weight was recorded using a modified Mitutoyo digital caliper interfaced with a micro-processor. Substantial differences were noted in the incidence of digital patterning. The relative proportion of digital patterns I(l>2>3>4>5) and II (2 > 1 > 3 > 4 > 5) were NA 76.09%, 23.91%; JK 50.80% and 49.20% respectively. The distance between the pternion and the distal extremity of the second digit expressed as a percentage of die maximum foot lengdi (MFL) was found to be 98.60% (NA) and 99.60% (JK). In addition, the distance between the pternion and the distal extremity of the fifth digit relative to MFL was 82-60% (NA) and 85.00% (JK). The implication of these data is that the anterior margin of the JK foot makes a less acute angle with the long axis of the foot than the NA population. Additional information with respect to foot breadth leads to the conclusion that the shape of the JK forefoot differs from that of the NA, with the implication that unique shoe lasts for both populations are required for optimal shoe comfort.     

Simulation of the behavior of the calfskin used as shoe upper material in footwear CAD

The aim of this work is to propound a mechanical behavior model for simulating the deformation of the shoe upper material in gait for footwear CAD applications. The chosen material is calfskin. The proposed material behavior for the working range is a linear elastic orthotropic model which considers large deformation and membrane and bending loading. The model was obtained from tensile tests and validated with two experiments: a test to measure the leather resistance to damage on lasting and a test that models the shoe forming process using lasts. The framework of this work is the simulation of the footwear deformation while walking for footwear computer-aided design, and these tests have been chosen because, in them, the shoe upper material is deformed in a similar way to those deformations that occur during a complete step. The tests have been simulated using the Finite Element Method. The results of this simulation show that, in most of the cases, the orthotropic model closely represents the real behavior of the leathers analyzed in this work.