Methods and tools dedicated to shoes customization ... - IMProVe2011

Proceedings of the IMProVe 2011International conference on Innovative Methods in Product DesignJune 15 th – 17 th , 2011, Venice, ItalyMethods and tools dedicated to shoes customization forpeople with diabetesM. Germani (a) , M. Mandolini (a) , M. Mengoni (a) , R. Raffaeli (a) , E. Montiel (b) , M. Davia (b)(a) Università Politecnica delle Marche, Dipartimento di Meccanica(b) INESCOP, Instituto Tecnológico del Calzado y ConexasArticle InformationKeywords:FootwearCADDiabetesCorresponding author:Michele GermaniTel.: +39-71-2204969Fax.:+39-71-2204801e-mail: m.germani@univpm.itAddress: Via Brecce Bianche, 12,Dipartimento di Meccanica, 60131AnconaAbstractPurpose:Study and development of innovative tools in order to support the design and manufacturingof customised shoes for people with diabetes.Method:The approach is based on the identification of main critical stages of footwear customisationwhen patient parameters have to be properly used; medical knowledge formalisation istranslated in new software design tools that interest the footwear shape and the suitablematerials.Result:Rapid customisation of preventive shoes for people with diabetesDiscussion & Conclusion:“Diabetic foot” in one the main effects of diabetes; it is important to develop shoes able toprevent this kind of complication. This paper reports an approach and related design toolsthat allow customising shoes on the basis of patient features. Rapid manufacturingtechnologies have to be still analysed in order to complete the whole process.1 IntroductionDiabetes is a growing health problem round the world.World Health Organization estimates that in 2030 morethan 334 millions of persons will suffer from diabetes [1].Today, main problems for people with diabetes are due tothe complications that such sickness generates. One ofthe most relevant complications is called “diabetic foot”. Itoften leads to amputation. Peripheral neuropathy, a lossof feeling in the extremities, renders these individualsunaware of sores that develop on their feet until thewound becomes infected. Then, because of otherdiabetes-related complications, the infection often defieshealing and eventually leads to amputation. The maincause of foot ulceration in the adult neuropathy diabetic isthought to be the presence of abnormally high plantarpressures secondary to neuropathy. It is evident thatreduction of amputations can be achieved if it is possibleto effectively prevent the foot ulceration. Early diagnosisthrough a continuous foot monitoring can be applied. Butthe best approach is to wear suitable personalized shoesthat avoid the causes of ulcer. Despite needs, there is nota full user-centered footwear development due to thedifficulty to simultaneously take into consideration multipledesign aspects such as foot shape and biomechanics,materials performance for upper, insole and outsole,manufacturing methods. These factors affect cost,availability on the market and variety in terms ofaesthetics. In order to investigate this problem, a researchprogram (SSHOES) was started. It has been fundedwithin the Seventh European Framework Program. It aimsat developing a new paradigm and implementinginfrastructure for the creation of diabetes-orientedfootwear, based on demand product differentiation andpersonalization in order to achieve high quality andcustomer satisfaction. Specific addressed research topicsare: 3D foot digitalization systems, footwear design toolsdedicated to personalized biomechanical as well asaesthetics aspects, adaptive production technologies, etc.This paper is focused on the adopted footwear designapproach and the results regarding with theimplementation of the supporting software systems. Aftera brief review of tools dedicated to shoes customization,the design approach will be described. A prototypaldesign system implementation will be proposed in order tosupport personalized shoe development. Main developedfeatures consist of the possibility to input data fromdedicated sensors such as foot scanners and pressuremeasuring systems, to elaborate patient medical andbehavioural data, to provide as output a set of shoedesign parameters and finally developing virtual models ofmain customized shoe components.2 Related worksAdvanced Computer-Aided solutions can highlyimprove the efficiency of footwear industry internal andexternal processes. Dedicated CAD (Computer AidedDesign), Reverse Engineering and Rapid Prototypingsystems are examples of tools usable in order to reduceshoes development time and product cost [2].Various specific CAD systems to create 3D virtualmodels of shoes have been developed [3-4]. They aremainly oriented to manage manufacturing processes suchas upper cut, shoe sole molding, etc…, or to marketingpurposes, thanks to 3D rendering tools. The productconceptualization is basically limited to the aestheticevaluation neglecting the desired shoe functions, theachievable comfort and the shape customization. These698

M. Germani et al. Methods and tools for shoes customisationaspects are ever more important in order to satisfy thespecific customer requirements. The creation ofcustomized shoes has been investigated in severalresearch activities [5-6]. They face the digitalization ofcustomer’s feet by adopting non-contact 3D scanningsystems and the related range data elaboration softwaretools in order to provide a virtual foot model [7] or a set ofmeaningful of cross-section measurements [8]. The mostadopted 3D acquisition tools are based on thetriangulation principle by laser scanning and structuredlight measurements. Examples of contact digitizers areAmfit Digitizer by Amfit and Orthofit scanner by FootClinic. Examples of laser-based scanners dedicated tocustom shoes for patients with special feet diseases areLightbeam 3D by Corpus, Yeti by Canfit, ERGOscan byCreaform, etc.[9]. Once feet models have been obtained,a digital model of the last is necessary as it is the baseover which the shoe components are designed. Generallythe most suitable last can be selected from a database ofpossible ones and its shape deformed accordingly to thedesigner intent.The aim of other research activities was to set efficientmanufacturing systems based on the automation ofphases when a high number of possible productivevariables have to be managed as in shoes customizationoccurs. Some interesting solutions are described in [10]and [11].It is worth to underline that such technologies are onlypartially implemented in the majority of industrial contexts.Main reason for that can be found in footwear commercialsystems that often lack of robust functionalities that causeinefficiencies and waste of time. In these cases, operatorsshould use workarounds to achieve the desired results.Furthermore, customers complain absence of tools tosupport the implementation of their specific processes.Resuming the main critical aspects of this set ofsystems regard:the integration between the SW adopted to managethe digitalization and the CAD-based systems usedto elaborate the geometry according to the chosenlast, the medical parameters, the manufacturingtechnology, etc.; the formalization of rules that experiencedshoemakers use for achieving a right footwearcomponents design (last, insole, outsole, etc.); the adopted methods to enable footwear fitquantification according to the scanned footdimensional parameters [10];the definition of anatomical landmarks to facilitatefoot acquisition and its surface reconstruction [11];lack of tools to interface different software solutionspresent in the design and manufacturing cycle, oftenrequired to cope with non standard shapes. In fact,different proprietary file formats, linked to the specificCAD solution, have arisen during the last years, inorder to maintain own market share. This has causedhigh costs, low integration possibilities with othersystems, and consequentially lost of efficiency. Theresult has been that many companies rely ontraditional processes still employing 2D CADsystems;time and feasibility of 3D scanning in orthopedics andshoes stores.Speaking of shoes for people with diabetes additionalissues arise. Apart from the disease intrinsic factors,many extrinsic factors related to foot and footwear caninfluence diabetes progression and health (e.g. footpressure, movement of the foot in the shoe, lacing of theshoe, moisture permeability, insole geometry, stiffnessand shock absorption properties, sole depth, pitch,stiffness and how these alter over the length of the shoe).Each of these extrinsic aspects requires data andinformation from the specific patient in order to enableappropriate footwear personalization.Furthermore, changes of footwear performance overtime and/or patients’ use and ways to move can affect theclinical efficacy of footwear. Several commercial systems(e.g. Vorum by Canfit, FootWizard by Otto-Bock,SOLETEC by Shoemaster, etc.) try to achieve a fullcustomization of shoes and insoles for people with specialdiseases. Systems interoperability, integration,performance, implementation of biomedical andbiomechanical features and ease-to-use for non-expertusers (e.g. health care professionals who work withpatients with diabetes, orthopedics, etc.) are only someproblems limiting their application.Main practical problems to be faced are listed here: lack of suitable 3D modeling strategies of deformationto modify the last shape as the experts manually do;lack of criteria to model the insole and the whole shoein according to the medical criteria; lack of advanced tools in order to manageheterogeneous geometric and non geometric data(clouds of points, surfaces, images, pressure maps,disease characteristics, etc.)the impossibility of capturing foot in the desiredposition set up by the orthopedic technician;the right combination between the acquired footgeometrical data and the plantar foot pressure;the difficulty to design a proper insole in terms ofshape and materials in order to unload specific footzones.In this paper several software solutions are proposeddedicated to support the design phase, while future workwill be dedicated to integrate foot scanning with plantarpressure measurement and to improve manufacturingtechnologies.3 Footwear design approachThe proposed approach is based on an integratedproduct design framework for enabling the managementof the whole life cycle of shoes for diabetic people. Theapproach is based on a set of integrated softwaresystems. Such systems exchange information through aunique XML file containing patient as well asmanufacturing data involved in the entire shoe lifecycle.A diabetic patient needs at first specific analysis, inorder to evaluate important bio-mechanical parameters(first MPJ motion & torque, plantar pressure, ankledorsiflexion, dorsal geometry, foot pronation, etc.). Thesedata are later used to design the best shoe required to fithis/her specific needs. In order to measure aboveparameters, commercial solutions could be insufficient ornot sufficiently integrated. Therefore, new measurementsdevices and the integration of already existing ones inportable systems are going to be investigated. Theseintegrated systems mainly concern foot geometry andpressure acquisition during a complete gait cycle.During subsequent shoe design phase, mentioned biomechanicalparameters are converted in footwearfeatures. In case of diabetic shoes they are: rocker angle,heel height, apex position, apex angle, sole stiffness, etc.,as shown in figure 1Fig. 1. These parameters define thegeometry of a diabetic rigid sole. A rigid sole is designedfor a corrective gait and helps preventing feet ulceration.June 15th – 17th, 2011, Venice, Italy699Proceedings of the IMProVe 2011

M. Germani et al. Methods and tools for shoes customisationFig. 1: Diabetic footwear features.Data coming from measurement system can be storedin the XML data file. Such file is divided in two parts, thefirst one concerning patient data, while the second oneconcerning shoes.Main patient data regards: Patient information: general patient personal data; Bio-mechanical parameters: values of thoseparameters, which should be used for designing anad-hoc pair of shoes; Feet mesh: feet dynamic shape acquired during acomplete gait cycle. Foot shape variation duringwalking is combined with the static one relative tosingle foot geometry digitized when the patient isstanding; Feet pressure maps: for each foot during a completegait cycle. Pressure distribution changes during gaitcycle in relation to foot geometry. From mapselaboration, isobar curves or maximum pressurepoints, are extracted and stored. Second part of the XML file defines the shoe: Footwear features: list of parameters which drivesfootwear component design; Last model: file contains information about lastsgeometry, which are used during shoesmanufacturing phase; Outsole model: outsole geometry derives from thelast and other patient specific parameters. Geometryof several outsole layers and relative materials arestored;Insole model: this part of shoe is strongly customizedon patient and it is derived from foot pressuredistributions. Geometry of insole layers and relativematerials are written in the file.In the figure 2, an example of XML file standardizationis provided for geometrical data.In the following sections the dedicated CAD system isdescribed in more detail.Fig. 2: Diagram representing geometrical informationinterconnection using UML class diagram4 Footwear design systemThe core of the proposed diabetic footwear designprocess is the biomechanical CAD (B-CAD). It embedsthe footwear integrated design system and drives theproduct geometries and materials definition providing datafor adaptive manufacturing technologies.B-CAD composes of a knowledge-based (KB) system,a material selector for insole and outsole and a properCAD environment. KB manages and configures footwearfrom initial patient data gathering, to shoes design, tillmanufacturing and usage. The CAD environment will behere extensively discussed focusing on its mainfunctionalities. Insoles and outsoles modules are underdevelopment together with the material selector systemsince they are strictly interrelated. Insole and outsoleshapes will be based on design criteria deriving from thecombination of measured foot pressure and materialbehavior.To deal properly with all involved geometry elements(mesh, curves, NURBS surfaces, …) the SoftwareDevelopment Kit of a low-cost commercial CAD software(Rhinoceros v.4.0 by McNeel) has been employed. Itprovides access to the CAD geometric kernel and it allowsthe implementation of new specific modelingfunctionalities. Dedicated software applications has beendeveloped using the programming language MS VisualBasic.NET. The usage of a common platform for the set ofrequired modules allows a homogenous environment andhigh data exchange capabilities.The first module of the B-CAD system enablesspecialists to fix shoes design parameters accordingly tothe specific patient needs. This module drives thefootwear designer in finding appropriate geometricsolutions by applying decision-making rules based onexperience, medical data and measurements of the mostsignificant biomechanical variables of the patient.System inputs are both geometrical and nongeometrical as summarized in table 1. Geometricalparameters are represented by foot shape in static anddynamic conditions, foot motion in gait and elaboratedfoot pressure maps. Geometries are mainly employed inshoe components design phase but, at this stage, theyJune 15th – 17th, 2011, Venice, Italy700Proceedings of the IMProVe 2011

M. Germani et al. Methods and tools for shoes customisationprovide additional clinical variables as global footdeformity and pressures concentration level.Besides, foot motion data are used for driving 3Ddynamic foot geometry simulation. It employs data pointsfrom the foot surface measured during the gait cycle todrive corresponding data points in 3D geometric footsurface model derived from laser scanning system. Thesimulation is used to identify ideal flexion line in the shoe,foot girths values and fluctuation during motion and alsoinsole profile curves.On the other hand, non geometrical parameters, alsoreferred as clinical variables, have been identified in orderto be: user activity level, types of activities undertaken,vascular status, neuropathy status, plantar soft tissueproperties, sweat production, site and nature of skinlesions, range of joint motion, muscle shortening. Theseparameters are assessed by the orthopedic specialist andeach one ranked on a scale from 1 to 10.BiomechanicalvariablesActivity levelTypes of activitiesundertakenVascular statusNeuropathy statusPlantar soft tissuepropertiesSweat productionSite and nature of skinlesionsRange of joint motionMuscle shorteningAssessmentOrthopedicspecialistOrthopedicspecialistOrthopedicspecialistOrthopedicspecialistOrthopedicspecialistOrthopedicspecialistOrthopedicspecialistOrthopedicspecialistOrthopedicspecialistType of dataRank 1 to 10Rank 1 to 10Rank 1 to 10Rank 1 to 10Rank 1 to 10Rank 1 to 10Rank 1 to 10Rank 1 to 10Rank 1 to 10Foot geometry Foot digitizer 3D mesh modelFoot deformity Foot digitizer Rank 1 to 10Pressures map Foot digitizer Pressures mapPressures concentration Foot digitizer Rank 1 to 10Ideal flexion lineFoot girths values andfluctuationInsole profile curvesDynamicsmoduleDynamicsmoduleDynamicsmoduleNumeric valueNumeric intervalsProfile curvespractice have shown to be optimal for certain patientcategories.4.1 CAD systemThe input for designing insole and last is given by theresults of a dedicated measurement system constituted bya 3D laser scanner, baropodometric platform and a gaittool for static and dynamic analysis. Outputs of thissystems are a sequence of foot pressure maps (.bmp or.csv files) and foot geometries (.stl mesh). The pressuremaps sequence is acquired during foot scanning, sopressure distribution over time can be analyzed. In fact,during scanning time span, patient could slightly move hisbody and pressure distribution changes.Foot Pressure Viewer reads a sequence of pressuremaps and extracts that one which better represents footplantar pressure, following a specific algorithm thatmaximizes the quantity of information that is available onthe map.Pressure map is acquired in a discrete way andrepresented by a cloud of points. Only points whosepressure value is not zero are included. Map point X andY coordinate correspond to pressure sensor cell midpointwhile Z represents pressure value.An algorithm works on the point cloud in order toextract characteristic points, such as 1st and 5thmetatarsal points, most prominent points on heel area,medial metatarsal point, centre of pressure (COP) andpressure map barycentre (figure 3). Foot axis is alsocalculated, as the line that minimizes deviation amongpressure points (points are projected on XY plane). 1stand 5th metatarsal points are calculated as the mostexternal points of pressure map. Medial metatarsal pointis the midpoint for the two previous ones. Most prominentpoints are computed in a local reference system that isaligned with the foot axis. Between two possible points, ischosen that one which is more distant from medialmetatarsal point. COP is defined as midpoint betweenmost prominent and medial metatarsal ones. Barycentreis calculated as a weighted average point, where pressurevalue is used as weight.Tab. 1 Clinical and biomechanical variables.The whole clinic and biomechanical variables systemis elaborated by the knowledge based software in order toelaborate appropriate footwear components designparameters (FCDP). In particular outputs refers to lastselection, last typical measurements and girths, uppermaterials selection, shoe components options, heel heightand shape prescriptions.The software that matches biomechanical parameterswith design parameters is based on a knowledge baserepository represented by evidences from the literatureand a wide selection of real test cases. The first type ofknowledge is implemented in algorithms which basicallyfilter the possible range of design parameters on the baseof the specific patient data when explicit rules can beformulated. On the other hand real test cases are storedas a set of design solutions which experience andFig. 3: Extraction of characteristic points of a pressure mapFoot Pressure Viewer has also a functionality toautomatically align foot mesh with pressure map, sincethese data are generally expressed in different referencesystems. The transformation matrix necessary to overlappressure to geometry is calculated from an alignmentprocess of the convex-hull curve of foot sole mesh andconvex-hull curve of pressure map. This approach hasshown good reliability and efficiency. First curve isgenerated as follow: from foot mesh, a new one isgenerated from facets with vertices Z-coordinate less thana threshold value (foot scan is generally aligned along Xaxis and its sole on XY-plane). XY plane projectedJune 15th – 17th, 2011, Venice, Italy701Proceedings of the IMProVe 2011

M. Germani et al. Methods and tools for shoes customisationsilhouette of this mesh is calculated and then the convexhullof obtained curve is derived. On the other hand, thesecond curve is build from the convex hull of pressurepoint cloud.Curves alignment is based on an Iterative ClosestPoint (ICP) algorithm (figure 4). For a correct and fastresult a rough pre-alignment algorithm is used. Pressurepoints bounding box is overlapped to foot sole meshbounding box. In this phase, foot orientation isguaranteed by considering pressure map characteristicpoints. In fact, it must be avoided to overlap toe of footmesh with pressure map heel zone. ICP works on pointsclouds derived from uniform curves sampling. Eachiteration transformation is computed using a Moore–Penrose pseudoinverse matrix.accordingly to color information: point with red color havemaximum elevation, while blue points have zero elevation.As input parameters grid resolution and maximum pointselevation can be specified. Higher number of pointsmeans higher accuracy of final isobar curves whiledecreasing grid resolution curves are smoother.Fig. 6: Pressure surface from pressure map to be used forisobar curves calculation.Fig. 4: Pressure map with foot geometry alignment by ICPapplied to convex-hull curves.As alignment has been reached, pressure map isprojected on the foot sole mesh (figure 5). Result of thisoperation is a new mesh corresponding to foot sole withcolored vertices. Projection is created from a planarquadrilateral mesh, with a texture representing pressuremap applied on it. The texture is created from pressurepoint converting Z coordinates in color information. Inparticular, maximum pressure level has been converted inred, while minimum one in blue. During this phase, alsoan improvement of texture image resolution has beenperformed in order to improve final quality of projectionresult. In fact baropodometric platforms have lowresolutions, generally 2÷4 sensors for square inch.Fig. 7: Examples of isobar curves. In black feet profile from3D mesh is drawn.Once geometrical data about foot and pressure hasbeen acquired and elaborated, next step regards thedefinition of the model of a customized last. Last shapemust be drawn in order to cope with patient pathology,medical prescriptions, but also, if possible, with fashiondictates. The result of the process consists of a set ofNURBS surfaces. They are afterwards used to physicallyproduce the lasts by milling and to be unrolled to pieceswhich can be cut from leather.A set of modeling functionalities has been implementedin the Last Designer module. They cope with foot andlasts points cloud data, lasts geometry editing,modifications and exporting to milling devices and leathercutting. Figure 8 shows the sequence of operations tocarry out in order to obtain a customized last. Firstly, atriangulated mesh representing the last geometry isobtained from points cloud data. Minolta V9i laser 3Dscanner has been chosen for 3D last digitisation. Themain advantage of such system is that it can besuccessfully employed also for acquiring textures.Fig. 5: Foot pressure projected on sole foot mesh.Isobar curves have been calculated from a Nurbssurface obtained from pressure map (figure 6). Curvesare calculated slicing this surface with parallel to XY andequidistant planes (figure 7). The number of curves isspecified by user. A control points grid is defined on theXY-plane and points elevation (z-coordinate) is setFig. 8: Last Designer functionalities and flowchartThe digitization may lead to some errors in the STLmodel and some corrections must be performed: holesfilling, non manifold faces deleting, noise reduction, meshdecimation, isolated triangles deleting, etc… All theseoperations have been implemented through automatedcommands, easy in using also for non-skilled operators.June 15th – 17th, 2011, Venice, Italy702Proceedings of the IMProVe 2011

M. Germani et al. Methods and tools for shoes customisationStandard reverse engineering algorithms have been usedand optimal parameters selected on the base of thespecific application.A standard last reference coordinate system has beenfixed. The operator identifies some conventional points onthe last scan in order to fix styling and space references.The last is then positioned in a predefined coordinatesystem.Then, last base-curves can be drawn. These curvesinclude base edge curves and ankle curves; they arenecessary for the subsequent phase of surfacereconstruction. A semi-automated approach has beenfollowed. Through curvature analysis, the softwareextracts sub-clouds of points with higher curvature. Thecurves are then obtained fitting the point clouds (seefigure 9).An additional curve network is generated as sectionsof mesh and conveniently trimmed and smoothed. Analgorithm that uses base-curves to position and orientsection planes performs this operation. The curve networkis then used to build NURBS surfaces as ordinary lofts.In this way, a sort of automatic reverse engineeringprocess has been obtained. This approach is particularlyconvenient for lasts. In fact, surface reconstruction has tobe rapidly repeated many times, and automation makes iteasy also for operators with poor reverse engineeringknowledge.Fig. 9: Automatic Reverse Engineering process. Referencecurves from mesh curvature and curves grid from meshsectionsOnce a NURBS surface has been obtained, it can bemodified in order to meet specific patient needs. Anumber of standard modifications have been identifiedfrom manual operators’ expertise. Typically, thesemodifications refer to heel height variation, length or widthincrement, profile curves redrawing (figure 10). In order topreserve the styling and aesthetic shape, the amount ofsurfaces distortion has to smoothly vary from a maximumcorresponding to a target section decreasing toward theareas where deformation is not needed. The algorithm isbased on the simultaneous displacement of curves andsurfaces control vertices on parallel planes on the base ofsuitable deformation functions.Analogous approach has been followed for othermodifications that target diabetic feet necessities. Theoperator uses these functions in a proper sequence inorder to achieve the required last shape that canconsiderably vary from the starting one.Eventually, NURBS surfaces can exported in IGESformat to milling machines to obtain a physical last or toother software packages for leather pieces preparing.Fig. 10: Example of last virtual modification. Control verticesdisplacement smoothly decreases from a target planeThe further software module is used when last designphase is completed. It is composed of three main groupsof functionalities: the first one is used to position and alignfoot with last, the second one to measure foot and lastand the third one to export measures and geometriesdefined during the measurement process.Lasts and feet are both characterized by a set of basicpoints. The definition of some of them correspondsbetween foot and last. The module imports both last andfoot and user specifies if foot has been digitized with thesole on the ground or using a raised heel.After import procedure, Foot Last Fitting moduleautomatically aligns geometries on the base of a quitecomplex procedure. As first step, a set of four axes arecalculated: foot axis, last turning axis, foot and turningsole axis (projection of previous axes respectively on footor last sole surface). Foot axis is defined as the linepassing through most prominent and medial metatarsalpoints (respectively HL and CL in Fig. 11). Turning axis,instead, is the line passing through the two mostprominent points of a last, one in the heel zone and theother one in the toe zone.Orientation procedure is based on the following set ofgeometrical criteria: foot and last axis is aligned along Xaxis, symmetry plane corresponds to XZ plane, mostprominent points are on positive Z axis, foot and last soleare on XY plane, foot and last axis are tangent to X axison a specific point (projection of medial metatarsal pointon foot and last sole axis).Fig. 11: Criteria for the orientation of foot and last in univocalmanner.Once geometries are aligned measuring phase isperformed (figure 12). At first foot and last basic points arecomputed. Then, measurements are calculated asdistances or extracted curve lengths. They include: footand last width, length, 1st and 5th metatarsal distance andangle, insole length, waist length, big toe tip movements,big toe tip vertical compression, etc.Other typical measures are relative to followingsections: heel, high instep, medium instep, ball, toe, toeperpendicular and any other user defined section. Foreach section, section plane can be visualized (inclinationJune 15th – 17th, 2011, Venice, Italy703Proceedings of the IMProVe 2011

M. Germani et al. Methods and tools for shoes customisationdetermine foot injuries. 1 st Joint will be generallycharacterized by soft materials (low stiffness), in order toredistribute insole forces on close areas.Most interesting results concern the integrated shoedesign phase, in fact, the definition of a single CADplatform for shoe components design allows increasingefficient collaborative design among companies withdifferent competencies (last, insole and outsole). Shoedata sharing and use during design phase of componentshas been improved by the definition of XML datafile. EachCAD module can directly read and write from this file,allowing to transmit from one module to another one asmore information as possible. In this way, it will be alsopossible to make parallel some design phases, such asinsole and outsole design.CAD module is based on dedicated commands fordiabetic feet speeding up designing phase. An operatorcan start from the most suitable last and he/she canmodify it in order to respect footwear features for thespecific patient. Insole and outsole design is faster byusing the proposed process because some usefulinformation, like isobar curves, have been calculatedduring patient data gathering phase. The insole-outsoledesign system used for experimentation does not adoptthe material selector and the automation of insole-outsolemodeling, thus further improvements will be surelyachieved. Foot-last fitting module allows thestandardization of procedures used to compare foot andlast, in order to establish how a last is fitting a foot. Byusing this software an objective evaluation is done, ratherthan a mere qualitative one. In few seconds, a technicianis now able to know more than one hundred of measuresfor foot and last; otherwise, a manual measurementprocedure requires about a few tens of minutes. Averagetime measured for carrying out the main phases ofpersonalized shoe design on 20 pairs of shoes aresummarized in table 2.Foot pressure andgeometrymeasurement andpreliminary dataelaborationFootwear featurescalculationFoot pressurevisualizationTraditionalprocess[minutes]Patient data gathering15(foot geometryis manuallymeasured andfoot pressureis reported in2D files)Proposedprocess[minutes]3(for this phasethe newprocessproposes atraditional 3Dscanner and abaropodometricplatform; the“Minilab” is notstillexperimented)Footwear features calculation20 4(materialselector is notstillexperimented)Footwear integrated designImprovement[minutes]-12-18- 2 +2Last 40 20 -20Insole-Outsole 25 20(the currentadvantage isdue to the dataderiving fromthe pressureviewer tool: thebenefits of theInsole-OutsoleDesignermodule are notconsidered))Foot-Last fitting 35 2 -33-5Total time 135 51 -86Tab. 2: Time for data gathering and footwear design forcomparing traditional and developed systems (averagemeasured time for a pair of customized shoes)The most important innovations proposed by thisresearch project are summarized in: Integrated framework of CAD systems for insole,outsole and last design for diabetic patients: theintegration of last, insole and outsole design softwaretoward a special framework using the same CADsystem (Rhinoceros), it allows the transparent dataflow from one system to the other one. In this way,information generated by a framework module areeasily used by another software as input data. Theexample is given in § 5, where isobar curvescalculated by Foot Pressure Viewer are gathered bythe Insole designer, in order to build insole geometry; Definition of links between footwear design featuresand biomechanical parameters: in this project hasbeen defined a last that can be used in case ofdiabetic people with a set of outsoles. These ones,have been parameterized by four main footweardesign features (apex angle, apex position, rockerangle and sole stiffness), which are the mostimportant in terms of pressure reduction on 1st Pointjoint. Links between footwear features andmechanical parameters are stored within a database,which, using specific Neural Networks Algorithms,they allow the definition of the best shoe for a specificpatient; Definition of criteria which allow the orientation in thespace of feet and relative lasts in an objective way: aset of criteria for relative last and feet orientation hasbeen defined (§ 4.1) in order to position them in arational way, before take measures. Using suchcriteria, feet and lasts measure can be comparedduring last design or verification phases. Definition of measure on lasts and feet in order tocompare them: a set of measures and relative rulesfor their revelation on a geometry (feet and lasts)have been defined. Definition of rules for insole materials selection: insoleand outsole common materials have been testedwithin laboratories with the aim to define theirmechanical properties (stiffness above all). The rulesallow the definition of link between biomechanicalparameters (only foot pressure till now) and insolematerials, as already defined in § 5.6 ConclusionsLiterature overview shows that there is a need ofdedicated systems to support the development of shoesfor people with diabetes and on the contrary, there are notavailable technologies to effectively overcome allproblems implied in footwear customization, flexibility,rapidly and quality.A general framework based on a KB system formanaging the whole shoes development cycle is defined.It sets the basis for innovating the whole process fromdesign, to manufacturing and retailing. The paper isfocused on the description of the adopted approach todefine the design framework and on the preliminaryresults about the implementation of the CAD-basedplatform for customized shoes design. Developedmodules (KB system, foot pressure viewer, last designerJune 15th – 17th, 2011, Venice, Italy705Proceedings of the IMProVe 2011

M. Germani et al. Methods and tools for shoes customisationand foot-last validation tool) are only a part of the wholesystem but they showed interesting advantages respectto the traditional shoemakers way of doing. The proposedsystem framework tries to integrate in a single tool thedigitalization and the CAD functionalities used toelaborate the geometry according to the chosen last, themedical parameters, etc. It allows to effectively combinethe foot acquired geometrical data and the plantar footpressure map. Finally it is based on expert shoemakersknowledge in order to model the last (and in the nearfuture also insole and outsole) within a highly usable 3Ddedicated CAD system.Future research will be concentrated both on thedevelopment and optimization of hardware tools forsimultaneously acquiring the dynamic 3D foot shape andthe related variable plantar pressure and on theimplementation of further design modules (insole-outsole,material selector, last valuator). In parallel many effortswill be done to completely develop the whole frameworkand relative adaptive manufacturing systems.[12] Luximon, A.; Goonetilleke, R.; Tsui, K.: A fit metric forfootwear customization, 2001 World Congress on MassCustomisation and Personalization, MCPC 2001, 2001.[13] Kouchi, M.; Mochimaru, M.: Development of a LowCost Foot-Scanner for a Custom Shoe Making System,5th Symposium on Footwear Biomechanics, Eds. E.Hennig, A. Stacoff, 58-59, 2001.AcknowledgementThis research is funded by the European Community’s7th Framework Programme within the SSHOES project(NMP2-SE-2009-229261), which involves 11 partnersfrom University, Research and footwear industry.References[1] www.who.int/diabetes[2] Bertolini, M.; Bottani, E.; Rizzi, A.; Bevilacqua, M.:Lead time reduction through ICT application in thefootwear industry: A case study, Int. J. ProductionEconomics, 110, 198–212,.2007.[3] Raffaeli, R.; Germani, M.: Advanced Computer AidedTechnologies for Design Automation in FootwearIndustry, IDMME-VIRTUAL CONCEPT 2008, 8-10October 2008, Beijing - China, 2008.[4] Smith, G.; Claustre, T.: A case study on conceptdesign and CAD modelling in the footwear industry,International Design Conference, DESIGN 2006,Dubrovnik - Croatia, 2006.[5] Boër C.R.; Dulio, S.: Mass Customisation andFootwear: Myth, Salvation or Reality?, Spinger, ISBN:978-1-84628-864-7, 2007.[6] Luximon, A.; Luximon, Y.: Shoe-last designinnovation for better shoe fitting, Computers in Industry,60(8), 621-628, 2009.[7] Redaelli, C.; Sacco, M.; Dulio, S.; Boër C.: Analysisof cultural gap for customized products, 3rdInterdisciplinary World Congress on Mass Customisationand Personalization, MCPC 2005, 2005.[8] Luximon, A; Goonetilleke, R.S., Zhang, M.: 3D footshape generation from 2D information, Ergonomics 48(6), 625–641, 2005.[9] Rutschmann, D.: The mobile and affordable lightbeam® 3D foot scanner for best fitting shoes, 3rdInterdisciplinary World Congress on Mass Customisationand Personalization, MCPC 2005, 2005.[10] Carpanzano, E.; Ballarino, A.; Jovane, F.: Towardsthe new Mass Customisation and PersonalizationParadigm: needed next generation manufacturingtechnologies, 40th CIRP International Seminar onManufacturing Systems, Liverpool, 2007.[11] Sievanen, M.; Peltonen, L.: Mass CustomisingFootwear: the left foot company case, InternationalJournal of Mass Customisation, 1(4), , 480-491, 2006June 15th – 17th, 2011, Venice, Italy706Proceedings of the IMProVe 2011