机械英文翻译搅拌机.docx

机械英文翻译搅拌机.docx

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机械英文翻译搅拌机

机械英文文献翻译-延长搅拌机

机械英文文献翻译-延长搅拌机

HAVE'2007-IEEEInternationalWorkshopon

HapticAudioVisualEnvironmentsandtheirApplications

Ottawa,Canada12-14October2007

ExtendingBlender:

DevelopmentofaHapticAuthoringTool

SheldonAndrews',MohamadEid2,AtifAlamri2,andAbdulmotalebElSaddik2

MultimediaCommunicationsResearchLaboratory-MCRLab

SchoolofInformationTechnologyandEngineering-UniversityofOttawa

Ottawa,Ontario,KIN6N5,Canada

'sandrO71]@site.uottawa.ca,2teid,atifWabed]@mcrlab.uottawa.Ca

Abstract-Inthispaper,wepresentourworktoextendawellknown3Dgraphicmodeler-Blender-tosupporthapticmodelingandrendering.TheextensiontoolisnamedHAMLAT（HapticApplicationMarkupLanguageAuthoringTool）.WedescribethemodificationsandadditionstotheBlendersourcecodewhichhavebeenusedtocreateHAMLATFurthermore,wepresentanddiscussthedesigndecisionsusedwhendevelopingHAMLAT,andalsoanimplementation"roadmap"whichdescribesthechangestotheBlendersourcecode.Finally,weconclude

withdiscussionofourfuturedevelopmentandresearchavenues.

Keywords-Haptics,HAML,GraphicModelers,Blender,VirtualEnvironments.

I.INTRODUCTION

A.Motivation

Theincreasingadoptionofhapticmodalityinhuman-computerinteractionparadigmshasledtoahugedemandfornewtoolsthathelpnoviceuserstoauthorandedithapticapplications.Currently,thehapticapplicationdevelopmentprocessisatimeconsumingexperiencethatrequiresprogrammingexpertise.Thecomplexityofhapticapplicationsdevelopmentrisesfromthefactthatthehapticapplicationcomponents（suchasthehapticAPI,thedevice,thehapticrenderingalgorithms,etc.）needtointeractwiththegraphiccomponentsinordertoachievesynchronicity.

Additionally,thereisalackofapplicationportabilityastheapplicationistightlycoupledtoaspecificdevicethatnecessitatestheuseofitscorrespondingAPI.Therefore,deviceandAPIheterogeneityleadtothefragmentationanddisorientationofbothresearchersanddevelopers.Inviewofalltheseconsiderations,thereisaclearneedforanauthoringtoolthatcanbuildhapticapplicationswhilehidingprogrammingdetailsfromtheapplicationmodeler（suchasAPI,device,orvirtualmodel）.

ThispaperdescribesthetechnicaldevelopmentoftheHapticApplicationMarkupLanguageAuthoringTool（HAMLAT）.ItisintendedtoexplainthedesigndecisionsusedfordevelopingHAMLATandalsoprovidesanimplementation"roadmap",describingthesourcecodeoftheproject.

B.Blender

HAMLATisbasedontheBlender[1]softwaresuite,whichisanopen-source3Dmodelingpackagewitharichfeatureset.Ithasasophisticateduserinterfacewhichis

notedforitsefficiencyandflexibility,aswellasitssupportsformultiplefileformats,physicsengine,modemcomputergraphicrenderingandmanyotherfeatures.

BecauseofBlender'sopenarchitectureandsupportivecommunitybase,itwasselectedastheplatformofchoicefordevelopmentofHAMLAT.Theopen-sourcenatureofBlendermeansHAMLATcaneasilyleverageitsexistingfunctionalityandfocusonintegratinghapticfeatureswhichmakeitacompletehapto-visualmodelingtool,sincedevelopinga3DmodelingplatformfromscratchrequiresconsiderabledevelopmenttimeandexpertiseinordertoreachthelevelofcodeintotheHAMLATsourcetree.

HAMLATbuildsonexistingBlendercomponents,suchastheuser-interfaceandeditingtools,byaddingnewcomponentswhichfocusontherepresentation,modification,andrenderingofhapticpropertiesofobjectsina3Dscene.ByusingBlenderasthebasisforHAMLAT,wehopetodevelopa3Dhapticmodelingtool

whichhasthematurityandfeaturesofBlendercombined

withthenoveltyofhapticrendering.

Atthetimeofwriting,HAMLATisbasedonBlenderversion2.43sourcecode.

C.ProjectGoals

Aspreviouslystated,theoverallgoalfortheHAMLATprojectistoproduceapolishedsoftwareapplicationwhichcombinesthefeaturesofamodemgraphicmodelingtoolwithhapticrenderingtechniques.HAMLAThasthe"lookandfeel"ofa3Dgraphicalmodelingpackage,butwiththeadditionoffeaturessuchashapticrenderingandhapticpropertydescriptors.Thisallowsartists,modelers,anddeveloperstogeneraterealistic3Dhapto-visualvirtualenvironments.

Ahigh-levelblockdiagramofHAMLATisshowninFigure1.Itillustratestheflowofdatainthehapticmodeling.HAMLATassiststhemodeler,orapplicationdeveloper,inbuildinghapto-visualapplicationswhichmaybestoredinadatabaseforlaterretrievalbyanotherhapticapplication.Byhapto-visualapplicationwerefertoanysoftwarewhichdisplaysa3Dscenebothvisuallyandhapticallytoauserinavirtualsetting.AnXMLfileformat,calledHAML[2],isusedtodescribethe3Dscenesandstorethehapto-visualenvironmentsbuiltbyamodelerforlaterplaybacktoanenduser.

Traditionally,buildinghapto-visualenvironmentshasrequiredastrongtechnicalandprogrammingbackground.Thetaskofhapticallyrenderinga3Dsceneistedious1108

sincehapticpropertiesmustbeassignedtoindividualobjectsinthesceneandcurrentlytherearefewhigh-leveltoolsforaccomplishingthistask.HAMLATbridgesthisgapbyintegratingintotheHAMLframeworkanddeliveringacompletesolutionfordevelopmentofhapto-visualapplicationsrequiringnoprogrammingknowledge.

Theremainderofthepaperisorganizedasfollows:

inSection2,wepresenttheproposedarchitectureextensionsanddiscussdesignconstraints.Section3describestheimplementationdetailsandhowhapticpropertiesareaddedandrenderedwithintheBlenderframework.InSection4wediscussrelatedissuesandfutureworkavenues.

II.SYSTEMOVERVIEWANDARCHITECTURE

TheBlenderdesignphilosophyisbasedonthreemaintasks:

datastorage,editing,andvisualization.Accordingtothelegacydocumentation[3],itfollowsadata-visualize-editdevelopmentcycleforthe3Dmodelingpipeline.A3DsceneisrepresentedusingdatastructureswithintheBlenderarchitecture.Themodelerviewsthescene,makeschangesusingtheeditinginterfacewhichdirectlymodifiestheunderlyingdatastructures,andthenthecyclerepeats.

Tobetterunderstandthisdevelopmentcycle,considertherepresentationofa3DobjectinBlender.A3Dobjectmayberepresentedbyanarrayofverticeswhichhave

beenorganizedasapolygonalmesh.Usersmaychoosetooperateonanysubsetofthisdataset.Editingtasksmayincludeoperationstorotate,scale,andtranslatethe

vertices,orperhapsare-meshingalgorithmto"cleanup"redundantverticesandtransformfromaquadtoatriangletopology.Thedataisvisualizedusingagraphical3Drendererwhichiscapableofdisplayingtheobjectasawireframeorasashaded,solidsurface.Thevisualizationisnecessaryinordertoseetheeffectsofeditingonthedata.Inanutshell,thisexampledefinesthedesignphilosophybehindBlender'sarchitecture.

InBlender,dataisorganizedasaseriesoflistsandbasedatatypesarecombinedwithlinksbetweenitemsineachlist,creatingcomplexscenesfromsimplestructures.

Thisallowsdataelementsineachlisttobereused,thusreducingtheoverallstoragerequirements.Forexample,ameshmaybelinkedbymultiplesceneobjects,butthepositionandorientationmaychangeforeachobjectandthetopologyofthemeshremainsthesame.AdiagramillustratingtheorganizationofdatastructuresandreuseofsceneelementsisshowninFigure2.Asceneobjectlinkstothreeobjects,eachofwhichlinktotwopolygonalmeshes.Themeshesalsoshareacommonmaterialproperty.Theentiresceneisrenderedononeofseveralscreens,whichvisualizesthescene.

WeadopttheBlenderdesignapproachforourauthoringtool.Thedatastructureswhichareusedtorepresentobjectsina3Dscenehavebeenaugmentedtoincludefieldsforhapticproperties（e.g.,stiffness,damping）;userinterfacecomponents（e.g.,buttonpanels）whichallowthemodelertochangeobjectpropertieshavealsobeenupdatedtoincludesupportformodifyingthehapticpropertiesofanobject.Additionally,aninteractivehapto-visualrendererhasbeenimplementedtodisplaythe

3Dscenegraphicallyandhaptically,providingthemodelerorartistwithimmediatefeedbackaboutthechangestheymaketothescene.inthecurrentversionoftheHAMLAT.themodificationstotheBlenderframeworkinclude:

datastructuresforrepresentinghapticproperties,

aneditinginterfaceformodifyinghapticproperties,anexternalrendererfordisplayingandpreviewinghapticallyenabledscenes,scriptswhichallowscenestobeimported/exportedintheHAMLfileformat.

AclassdiagramoutliningthechangestotheBlenderrameworkisshowninFigure3.ComponentswhichareertinenttoHAMLATareshadedingray.HAMLATbuildsonexistingBlendersub-systemsbyextendingthemorhapticmodelingpurposes.Datastructuresforrepresentingobjectgeometryandgraphicalrenderingareaugmentedtoincludefieldwhichencompassthetactilepropertiesnecessaryforhapticrendering.

ToallowtheusertomodifyhapticpropertiesGUIComponentsareintegratedaspartoftheBlendereditingpanels.Theoperationstriggeredbythesecomponents

operatedirectlyonthedatastructuresusedforrepresentinghaticcuesandmaybeconsideredpartoftheeditingstepoftheBlenderdesigncycle.

Similarlytothebuilt-ingraphicalrenderer,HAMLATusesacustomrendlererfordisplaying3Dsscenesgrphcalandhaptcall,anisineednoftheBlenderrenderer.Thiscomponentisdevelopedindependentlysincehapticalandgraphicalrenderingmustbeperformedsimultaneouslyandsynchronously.Asimulationloopisusedtoupdatehapticrend