Physical models continue to form an essential outcome from industrial design practice for
both student and professional. Whist the professional may be removed from the “hands-on”
model build by employing the services of a modelmaker, students rarely have such resources.
Indeed it was (and in many institutions still is) considered an essential part of the education
programme for students to develop modelmaking skills and experience the physical interaction
with form and material. However, the advent of remote model building technologies via rapid
prototyping and computer controlled machining, has given students an alternative, enabling
them to become increasingly removed from such interaction.
As increasing numbers of industrial design courses utilise remote model build technologies,
the emergence of three dimensional (3D) digital modelling via a haptic feedback device may
offer a route whereby students can continue to be involved with tactile design modelling.
Acknowledging the need to utilise digital design techniques, this paper investigates the
capabilities of haptic modelling for use within industrial design practice, with the aim of
discussing its suitability for student use. The research is based on an industrial design case
study for a communication device that was undertaken by the authors

Christopher Dean (4243144)

Dave Cheshire (7151453)

Mark Evans (1258356)

English

Loughborough University Institutional Repository

   This item was submitted to Loughborough’s Institutional Repository by the author and is made available under the following Creative Commons Licence conditions.      For the full text of this licence, please go to: http://creativecommons.org/licenses/by-nc-nd/2.5/  188Evans et alIDATER 2000  Loughborough UniversityAn investigation into the use of haptic modellingduring industrial design activityMark Evans*, Dave Cheshire+, Christopher Dean•Loughborough University*, Staffordshire University+, Sensible Technologies•AbstractPhysical models continue to form an essential outcome from industrial design practice forboth student and professional. Whist the professional may be removed from the “hands-on”model build by employing the services of a modelmaker, students rarely have such resources.Indeed it was (and in many institutions still is) considered an essential part of the educationprogramme for students to develop modelmaking skills and experience the physical interactionwith form and material. However, the advent of remote model building technologies via rapidprototyping and computer controlled machining, has given students an alternative, enablingthem to become increasingly removed from such interaction.As increasing numbers of industrial design courses utilise remote model build technologies,the emergence of three dimensional (3D) digital modelling via a haptic feedback device mayoffer a route whereby students can continue to be involved with tactile design modelling.Acknowledging the need to utilise digital design techniques, this paper investigates thecapabilities of haptic modelling for use within industrial design practice, with the aim ofdiscussing its suitability for student use. The research is based on an industrial design casestudy for a communication device that was undertaken by the authors.Keywords: haptic modelling, industrial design educationIntroductionAs a profession involved in the definition ofproduct form, industrial design makesextensive use of three dimensional (3D)models. These may vary in sophistication fromrelatively simple study models to fullprototypes (Knoblaugh, 1958:15; Kojima,1991:38). The type of model most associatedwith industrial design practice is theappearance model, which embodies the formof the production item but none of thefunctionality (Powell, 1990:11).Prior to the advent of remote model buildingtechnologies such as rapid prototyping andcomputer controlled machining, modelswould be produced by manual working andcraft-based techniques. Some designers takedesign decisions as they manually manipulatethe material, modifying it accordingly.As professional practice makes increasing useof remote model building technologies, theopportunity for the designer to be directlyinvolved in the shaping of material decreases.This has been shown to be the case with thefull range of models, from study models toprototypes (Sharbaugh in Carrabine 1999:24).However, one must acknowledge that thistakes place at a time when virtual evaluationhas increased, and 3D computer aided design(CAD) and computer aided industrial design(CAID) systems allow photorealisticvisualisation and real-time animation.One could argue that the experiencedpractitioner might have sufficient levels of skilland judgement to bypass the direct interactionwith form. Indeed, personal experience hasshown that such practice often takes placewhen deadlines are tight or resources arelimited. Students, however, need to activelydevelop their abilities in the manipulation ofform,  but this is of course happening at a timeof increasing access and requirements toemploy CAD and CAID, along with thepotential to build physical models usingremote model building. In response to theseconflicting pressures, the emergingtechnology of digital modelling using a haptic189IDATER 2000  Loughborough UniversityEvans et alfeedback device may have the potential todevelop and encourage the physicalmanipulation of form, albeit on a virtual level.Haptic feedback devices give the operator the“feel” of the virtual object. If the operatormoves a cursor onto an object on seen via themonitor, they actually feel its presence via anelectro-mechanical system attached to thepointing device.The authors, having backgrounds as bothdesign practitioners and educators, haveexplored the nature of haptic modelling,considering its potential for integration intoindustrial design practice and designeducation. It follows a programme of actionresearch that involved the industrial design ofa highly conceptual communication devicethat was produced as an entry for the NagoyaInternational Design Competition in May2000. The structure of the case study followsthe three phases of professional practice asidentified by Pipes (1990), involving conceptgeneration, design development, andspecification. These are now explored in somedetail.Concept GenerationThe brief for the communication devicespecified that its form should cross theboundaries between what we consider to bejewellery and consumer product. The designwas to have some of the functionality of amobile telephone, without the transient feelof a polymer consumer product. Conceptgeneration was undertaken using paper-basedsketching, examples of which can be seen inFigure 1.Whilst CAID was available throughout theproject, the industrial designer felt that theapplication of this technology wasinappropriate at the concept generation stagedue to the lack of spontaneity afforded by itsmodelling methods. This is identified by Pipeswhen he states that “Conventional CAD at anearly stage can stifle creativity by its insistencethat the designer provides the system withexact dimensional and geometric informationright from the start”. (1990:88)A small brooch-like product emerged from theconcept generation phase, its form basedaround an elliptical body with a large answerbutton. Other functionality was accessed viathree smaller buttons positioned on one end.The speaker/microphone was located on theopposite edge.The paper-based sketches provided theindustrial designer with sufficient detail onform and size to progress to the second phaseof design development. If operating to a moretraditional design methodology, this phasemay involve some modelling in “soft” materialssuch as Styrofoam, or even the manipulationof more resistant materials. For the purposeof the case study, haptic modelling was to beintroduced as an alternative.Design DevelopmentThe Phantom Desktop input device andFreeform 2 software were made available bySensible Technologies based in BostonMassachusetts. Twin 450Mhz processors with512MB of RAM were used to run the software,and support was provided by the SensibleTechnologies UK consultant. The PhantomDesktop input device can be seen in Figure 2.Figure 2 Phantom Desktop input devicewith Freeform 2 softwareFigure 1 Concept generation using paper-based techniques190Evans et alIDATER 2000  Loughborough UniversityAs a precursor to the product being modelled,an exploratory use of the technology wasundertaken. This involved an evaluation of theadditive and subtractive modelling techniques,along with smoothing operations andmanipulation of material density. The movefrom interacting with a physical object, to avirtual model, was initially found to be anunusual experience. However, as familiaritywith the software and system developed, themodelling capabilities of the media emerged.Indeed it soon became apparent that thehaptic modelling system was capable ofproducing forms that could not be generatedusing CAID, although the value of theserelatively abstract surfaces represents aseparate issue. Figure 3 shows one of themodels produced during the exploration ofthe media.After a period of familiarisation, it becameevident that the hardware and software couldbe used on two levels. The first involvedtechniques closely associated with CAD andCAID modelling, whereby forms could begenerated by non-haptic input e.g. creating asphere and numerically lengthening it in oneor more planes. The second technique ofhaptic modelling was not possible within aCAD or CAID system, and had the potentialto produce forms via various shapingoperations whilst receiving physical feedbacki.e. the operator could “feel” the virtualmaterial.Following the evaluation of the hapticmodeller, a decision was made to model thecommunication device using the functionalityof the Freeform 2 software. This wasparticularly appropriate for thecommunication device, as the body shape hadthe potential to be formed from a scaledsphere. The basic outer form of the productwas therefore modelled using the Freeform 2software without any haptic input. It wasgenerated from a sphere and distorted toproduce the required flat, curved form. Thespeaker/microphone notches were to bemodelled with the Phantom 2 haptic feedbackdevice, but it was not possible to generate thesmooth surfaces required. When the operatorperformed a haptic scooping operation, thesurfaces were excessively rippled as there wasno tight control of the motion. The designerwas attempting to create the effect one wouldachieve by taking a scoop of soft ice cream,leaving a cavity with smooth sides.It would have been possible to use morecontrolled modelling techniques withinFreeform 2 (using a guide to control the pathof the cut), but this was considered asignificant move away from haptic modellingand more related to CAID techniques. It wastherefore considered more appropriate to useCAID for the modelling of the basic form, andthe Phantom Desktop for specific surfacefinishes. The communication device wasmodelled as a surface using the DeskArtesCAID software in less than one hour.As the surface finish for the body of theproduct was to be modified using hapticmodelling, the CAID model was imported intoFreeform 2 as a .stl file. The imported surfacecan be seen in Figure 4.Figure 3 Model produced for evaluation ofmodelling capabilitiesFigure 4 Imported CAID surface191IDATER 2000  Loughborough UniversityEvans et alThe surface finish to be produced via hapticmodelling was not rigorously defined at theconcept generation stage as it was intendedto explore the possibilities of forming thevirtual material using techniques closelyrelated to craft-based interaction. Adjustmentsto the density of the virtual modelling materialand shape of tool resulted in the developmentof a hammered effect. The desired result wasachieved by using a rounded tool to “hammer”a relatively hard surface. The progression ofthe hammering can be seen in Figure 5.When completely hammered, the surface wassmoothed-out to soften corners. A secondseries of hammer blows were then applied togive a more irregular effect. This was againsmoothed-out on completion. The final finishcan be seen in Figure 6.The hammered surface was saved as a .stl fileand exported to the CAID system for theaddition of the remaining components andrendering. The rendered product can be seenin Figure 7, and as a photomontage with userin Figure 8.A second proposal was produced to exploitthe capability of the Freeform 2 software tomask surfaces to avoid deformation bysubsequent operations. This not only createsFigure 5 Haptic modelling of hammeredeffectFigure 6 Final hammered effectFigure 7 Rendered hammer finishFigure 8 Photomontage of hammer finishproduct with user192Evans et alIDATER 2000  Loughborough Universitymask, but it can also be used to define a cuton a surface and allow material removal. Whilstexploring the use of this functionality toproduce a rim around a scored section of thesurface, the potential to create a distinctiverandom transition between two surfacesbecame apparent. Figure 9 shows thedefinition of the masked area that was appliedusing a rounded tool with a haptic paintingtechnique.With the mask applied, it was possible toextract the inner surface and leave the outersection as a separate element. The insidesurface of the outer section was left with aseries of ridges that were created by therounded tool used to define the masked area.These appear as a series of ridges on the innersurfaces and can be seen in Figure 10.The surfaces were exported back into theCAID system for rendering, where the outersection was specified as silver, and the inneras a gloss purple plastic. A rendering of themasked product can be seen in Figure 11, andphotomontage with user in Figure 12.SpecificationThe specification of product form to designengineers and manufacturers who areconversant with digital design techniques isrelatively straightforward, requiring thetransmission of digital geometry in a mutuallycompatible format e.g. IGES or .stl.Figure 9 Definition of masked areaFigure 10 Outer surface showing internalridgesFigure 11 Rendered masked productFigure 12 Photomontage of masked productwith user193IDATER 2000  Loughborough UniversityEvans et alThe proposition for the hammered productwas for a low-volume, jewellery-like product.It would therefore be straightforward toconvert the surface geometry of the body intoa .stl file, thereby using the CAID data toproduce the components in wax using a rapidprototyping system such as the Sandersmachine. Investment casting could then beused to manufacture the components as adirect copy of the CAID model.ConclusionsAt the beginning of the project, theexpectations of the haptic modelling systemwere high. In fact they were too high.Assumptions were made that the modellingtechniques would be very close to those ofconventional foam and clay conceptmodelling. Unfortunately, the functionality ofthe software and hardware made it difficult toobtain the surface quality needed for bothrendering and production. This washighlighted by the attempts made to producea clean scoop when modelling the speaker/microphone detail. However, theresponsiveness of the haptic modelling systemto the generation of the hammered andmasked effects was impressive. Theproduction of the hammered effect was veryclosely associated with traditional hands-onmodelling, whereby the designer controlledthe manipulation of material whilstresponding to tactile feedback. The capabilityto create the masked area was not expected,but the potential for this technique resultedin the emergence of a design opportunity thatwas quickly exploited.For students of industrial design, the findingsof the case study indicate that hapticmodelling has its limitations. Whilst thestylistic trends within industrial design requiresmooth, crisp surfaces, the authors feel thatevery effort should be made to undertakephysical modelling using traditional fabricationtechniques as they cannot be reproduced byhaptic modelling. However, one can onlyassume that future development in thehardware and software for haptic modellingwill address the shortcomings identified in thecase study. Further work will then be requiredto re-evaluate such capabilities.In terms of the generation of random, almostcraft effects, haptic modelling has much tooffer. The authors feel that such a system maybe of interest to both practitioners andstudents of jewellery design. This would beparticularly relevant if the virtual materialcould emulate the characteristics of preciousmetals that may be too expensive to use.Indeed it may be possible to use hapticmodelling to practice on a virtual materialbefore working on the real (and expensive)precious metal.At present, there appears to be nothing toreproduce the feedback and effects achievedwhen interacting with a physical material. Theauthors therefore feel that students shouldcontinue to be encouraged to experience themanipulation of a variety of materials as ameans of developing their design skills. As thecapabilities of haptic modelling systemsdevelop, educators should be aware of theirincreasing capabilities as the boundarybetween the physical and virtual diminishes.References• Knoblaugh, R. R. (1958),  Modelmaking forindustrial design, McGraw-Hill, New York.• Kojima, T., Matsuda, S., Shimizu, Y. andTano, M. (1991), Models & prototypes,Graphic-sha Publishing, Tokyo.• Pipes, A. (1990), Drawing for threedimensional design, Thames and Hudson,New York.• Powell, D. (1988), Presentation techniques,Macdonald, London.• Sharbaugh in Carrabine, (March 1999), C3,Media Directories International, London.

An investigation into the use of haptic modelling  during industrial design activity

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An investigation into the use of haptic modelling during industrial design activity

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