3D-based reconstruction using growing neural gas landmark: application to rapid prototyping in shoe last manufacturing

Customizing shoe manufacturing is one of the great challenges in the footwear industry. It is a production model change where design adopts not only the main role, but also the main bottleneck. It is therefore necessary to accelerate this process by improving the accuracy of current methods. Rapid prototyping techniques are based on the reuse of manufactured footwear lasts so that they can be modified with CAD systems leading rapidly to new shoe models. In this work, we present a shoe last fast reconstruction method that fits current design and manufacturing processes. The method is based on the scanning of shoe last obtaining sections and establishing a fixed number of landmarks onto those sections to reconstruct the shoe last 3D surface. Automated landmark extraction is accomplished through the use of the self-organizing network, the growing neural gas (GNG), which is able to topographically map the low dimensionality of the network to the high dimensionality of the contour manifold without requiring a priori knowledge of the input space structure. Moreover, our GNG landmark method is tolerant to noise and eliminates outliers. Our method accelerates up to 12 times the surface reconstruction and filtering processes used by the current shoe last design software. The proposed method offers higher accuracy compared with methods with similar efficiency as voxel grid.

A new surface joining technique for the design of shoe lasts

The footwear industry is a traditional craft sector, where technological advances are difficult to implement owing to the complexity of the processes being carried out, and the level of precision demanded by most of them. The shoe last joining operation is one clear example, where two halves from different lasts are put together, following a specifically traditional process, to create a new one. Existing surface joining techniques analysed in this paper are not well adapted to shoe last design and production processes, which makes their implementation in the industry difficult. This paper presents an alternative surface joining technique, inspired by the traditional work of lastmakers. This way, lastmakers will be able to easily adapt to the new tool and make the most out of their know-how. The technique is based on the use of curve networks that are created on the surfaces to be joined, instead of using discrete data. Finally, a series of joining tests are presented, in which real lasts were successfully joined using a commercial last design software. The method has shown to be valid, efficient, and feasible within the sector.

Entre économie de la fonctionnalité et monopole : la United Shoe Machinery Company dans la première moitié du XXe siècle

L’histoire de la United Shoe Machinery Company (USMC) montre que la réalité ne s’adapte pas toujours aux simplifications de la théorie. Comme le signale l’économie de la fonctionnalité, la stratégie de l’entreprise de vendre l’usage plutôt que la machine fournit plusieurs avantages importants, mais elle a également contribué au fait que les usines de chaussures subissent une véritable dépendance technologique de cette compagnie et au fait que l’USMC soit parvenue à une domination monopolistique du marché. D’autre part, en remettant en cause les rudiments généraux de la théorie économique néoclassique, cette position de monopole n’a pas empêché que l’entreprise ait un fonctionnement efficace et ait facilité la modernisation technologique de l’industrie de la chaussure, aux États-Unis et dans d’autres pays.

Efficient tool path computation using multi-core GPUs

Tool path generation is one of the most complex problems in Computer Aided Manufacturing. Although some efficient strategies have been developed, most of them are only useful for standard machining. However, the algorithms used for tool path computation demand a higher computation performance, which makes the implementation on many existing systems very slow or even impractical. Hardware acceleration is an incremental solution that can be cleanly added to these systems while keeping everything else intact. It is completely transparent to the user. The cost is much lower and the development time is much shorter than replacing the computers by faster ones. This paper presents an optimisation that uses a specific graphic hardware approach using the power of multi-core Graphic Processing Units (GPUs) in order to improve the tool path computation. This improvement is applied on a highly accurate and robust tool path generation algorithm. The paper presents, as a case of study, a fully implemented algorithm used for turning lathe machining of shoe lasts. A comparative study will show the gain achieved in terms of total computing time. The execution time is almost two orders of magnitude faster than modern PCs.

Augmented and Virtual Reality techniques for footwear

The use of 3D imaging techniques has been early adopted in the footwear industry. In particular, 3D imaging could be used to aid commerce and improve the quality and sales of shoes. Footwear customization is an added value aimed not only to improve product quality, but also consumer comfort. Moreover, customisation implies a new business model that avoids the competition of mass production coming from new manufacturers settled mainly in Asian countries. However, footwear customisation implies a significant effort at different levels. In manufacturing, rapid and virtual prototyping is required; indeed the prototype is intended to become the final product. The whole design procedure must be validated using exclusively virtual techniques to ensure the feasibility of this process, since physical prototypes should be avoided. With regard to commerce, it would be desirable for the consumer to choose any model of shoes from a large 3D database and be able to try them on looking at a magic mirror. This would probably reduce costs and increase sales, since shops would not require storing every shoe model and the process of trying several models on would be easier and faster for the consumer. In this paper, new advances in 3D techniques coming from experience in cinema, TV and games are successfully applied to footwear. Firstly, the characteristics of a high-quality stereoscopic vision system for footwear are presented. Secondly, a system for the interaction with virtual footwear models based on 3D gloves is detailed. Finally, an augmented reality system (magic mirror) is presented, which is implemented with low-cost computational elements that allow a hypothetical customer to check in real time the goodness of a given virtual footwear model from an aesthetical point of view.

Footwear bio-modelling: An industrial approach

There is a growing need within the footwear sector to customise the design of the last from which a specific footwear style is to be produced. This customisation is necessary for user comfort and health reasons, as the user needs to wear a suitable shoe. For this purpose, a relationship must be established between the user foot and the last with which the style will be made; up until now, no model has existed that integrates both elements. On the one hand, traditional customised footwear manufacturing techniques are based on purely artisanal procedures which make the process arduous and complex; on the other hand, geometric models proposed by different authors present the impossibility of implementing them in an industrial environment with limited resources for the acquisition of morphometric and structural data for the foot, apart from the fact that they do not prove to be sufficiently accurate given the non-similarity of the foot and last. In this paper, two interrelated geometric models are defined, the first, a bio-deformable foot model and the second, a deformable last model. The experiments completed show the goodness of the model, with it obtaining satisfactory results in terms of comfort, efficiency and precision, which make it viable for use in the sector.

Selected characteristics of gait in women of different ages

In our research we have attempted to find out and compare force and time characteristics of gait in women. We measured and compare women in two age groups - 18-30 (group 1) a 46-60 (group 2). The average height of both groups was same, 167 cm, while the average weight and average body mass index were different (group 1 - weight 62 kg, BMI 22,3, group 2 - weight 68 kg, BMI 24,6). For measuring, pressure shoe insoles were used (Pedar Mobile, Novel Munich, 99 sensors, 100 Hz). Each person had three attempts: two trial attempts, the third one was measured. For observation, we selected three stances of each leg, always between the third and eighth stride. We measured force characteristics F1, F2, F3 and time characteristics t, t1, t2, t3. Significant differences between both groups were found in t3 on the left leg (time between peak force in active part of stance and peak force in passive part of stance). With applied force (F1, F2, F3) during stance, after recalculating per a kilogram of weight, no statistically significant differences were found.

Em busca da originalidade do patrimônio cultural na cidade-espetáculo: o caso da Casa Boehm em Joinville/SC

Este trabalho tem o intuito de discutir como um imóvel tombado na cidade de Joinville/SC vem respondendo ao mundo das influências contemporâneas da espetacularização. A Casa Boehm, hoje uma loja de calçados no comércio, foi construída em 1927 e tombada em 2001, por meio do Processo de Tombamento PFCC n. 627/003, de 10 de abril de 2000, homologado pelo Decreto n. 3.461/2001, do Governador do Estado, na época, Esperidião Amin. O imóvel vem sofrendo alterações físicas, que afetam princípios de unidade, volumetria, padrões de estilo arquitetônico, o que faz com surjam debates a respeito dos seus valores estéticos. A depender do gosto dos locatários, especialmente no que se referee às cores externas, sem autorização, vislumbra-se a partir da opinião dos participantes do Conselho de Patrimônio da cidade - COMPHAAN, a espetacularização que este bem vem suportando em nome de uma sociedade de consumo, que apenas visa o lucro, apesar de inúmeros debates teóricos acerca da preservação. Desta forma, quando se pensa em restauração de um patrimônio cultural edificado, a preocupação imanente é com a sua imagem subjetiva/simbólica, e ainda, não menos importante, no que se refere às cores utilizadas nas pinturas das edificações. A metodologia utilizada é qualitativa, por meio de pesquisa bibliográfica, documentais no Arquivo Histórico de Joinville – AHJ e na Fundação Cultural de Joinville – FCJ e, etnográfica. A etnografia, com nuances interdisciplinares, foi realizada nestes mesmos Arquivos da cidade de Joinville, nos arredores do bem em questão e analisando algumas impressões obtidas nas reuniões do Conselho de Patrimônio da cidade – COMPHAAN. Este estudo é parte integrante da pesquisa para doutoramento em Ciências Humanas, na Universidade Federal de Santa Catarina – UFSC. Parte-se da hipótese inicial de que as discussões que envolvem as cores em bens tombados têm se relacionado com a autenticidade e a integridade dos conjuntos nos centros históricos. Porém, vai além, já que o espetáculo buscado pelos gestores públicos, com intento de valorizar suas cidades, acaba por homogeneizar esses territórios em torno de uma ideia de patrimônio que tem sido questionada por alguns teóricos.