A new interface paradigm for motion capture based animation systems

Abstract. This paper proposes a new user interface paradigm for motion capture based animation systems, providing intuitive and efficient ways to visualize the main motion capture concepts and operations. A prototype system was built, implementing the prop

ANewInterfaceParadigmforMotionCaptureBasedAnimationSystems

FernandoWagnerSerpaVieiradaSilva1,2

LuizVelho1

PauloRomaCavalcanti2

JonasdeMirandaGomes1

{nando,lvelho,roma,jonas}@visgraf.impa.br

1IMPA–InstitutodeMatem´aticaPuraeAplicadaEstradaDonaCastorina,110,22460RiodeJaneiro,RJ,Brazil

2LCG-Laborat´oriodeComputa¸c aoGr´a ca,COPPE-Sistemas/UFRJCaixaPostal68511,21945-970,RiodeJaneiro,RJ,Brazil

Abstract.Thispaperproposesanewuserinterfaceparadigmformotioncapturebasedanimationsystems,providingintuitiveande cientwaystovisualizethemainmotioncaptureconceptsandoperations.Aprototypesystemwasbuilt,implementingtheproposedinterfacemodelandsupportedbya exiblearchitecturethatissuitabletoworkwiththemotioncapturemethodology.

keywords:motioncapture,animationsystems,computeranimation,graphicinterfaces,GUIparadigm,motioncontrol.

1Introduction

TheMotionCapturetechniquehasalreadysetitsplaceinthefutureofcomputeranimation.Thistechniqueprovidestoolsforhigh-qualityanimation,evenwhenreal-timeisrequired.

Initially,themaindrawbackofMotionCapturetechniqueswasthelackofef- cientwaystomodifythecapturedmotion,byadjustingorimprovingspeci cpartsthatneededtobechanged,withouthavingtorepeattheentireacquisitionprocessagain.

Abstract. This paper proposes a new user interface paradigm for motion capture based animation systems, providing intuitive and efficient ways to visualize the main motion capture concepts and operations. A prototype system was built, implementing the prop

Lately,however,severaltechniqueswereproposedtoprocesscaptureddata[9][11][12],providingtoolsformotionanalysis,modi cationandreuse.Thismakesmotionlibrariesmorevaluableforawideclassofanimators.

Mostofcurrentanimationsystemso erthepossibilityofusingmotioncaptureddatatogenerateanimations,butseveralsystemstreatthistechniqueasan“extratool”,orevenasasimpleplug-in.Therefore,ane ectivedescriptionofmotioncapturebasicconceptsisnotprovided.

Aninterestingandalternativeapproachwouldbetheconstructionofanani-mationsystemthatusesmotioncaptureasthekerneloftheentireanimationprocess.Thisleadstoanunlimitedrangeofpossibilitiestomanyanimators.Asanexample,thismotioncapturebasedsystemcouldbeintegratedwithhigh-endmotioncapturehardware,thuscreatingapowerfulenvironmentofmotionacquisitionandprocessing.

Inthiswork,weproposeanewuserinterfaceparadigmformotioncapturebasedanimationsystems,supportedbyanextensiblearchitecturethatincorporatesthe“stateofart”inmotioncaptureprocessingtechniques,andallowstheuseofstandardanimationmethods,suchaskeyframingorinversekinematics,aspowerfultoolstoimprovethesystem’s exibility.

Themaincontributionofthispaperistheintroductionofanelegantwaytodescribe,attheuserinterfacelevel,thebasicmotioncaptureabstractions.Wetreatcapturedmotionasapotentiallyreadyanimation,whichcanbemodi- edbyasetoftoolsembeddedinthearchitecture.Inthatway,aninterfacedescriptionofmotionoperationsandassociatedobjectsarede ned.

Aprototypesystemwasbuilt,implementingtheconceptsdescribedinthiswork.Thissystemwasusedtodemonstratethepotentialoftheproposedinterfaceparadigm.

Section2ofthispaperintroducesthebasicinternalstructuresoftheprototypesystem,togetherwithabriefdescriptionofitsarchitecture.Section3presentstheproposedinterfaceparadigmformotioncapturebasedsystems.Finally,conclusionsaregiveninsection4.

2System’sArchitectureandInternalStructures

Inthissection,wepresentaframeworkfortheanimationsystem.Also,abriefdescriptionofthearchitectureusedintheimplementedsystemisprovided.Thiswillgiveabetterunderstandingoftheapproachusedtobuildtheproposedinterfaceparadigm.

Abstract. This paper proposes a new user interface paradigm for motion capture based animation systems, providing intuitive and efficient ways to visualize the main motion capture concepts and operations. A prototype system was built, implementing the prop

2.1BasicInternalStructures

Thefundamentalstructureusedinthesystemiscomposedbytwoentities:anactorandmotions.

Theactoristreatedasaskeleton.Itstopologyisrepresentedbyagraphformedbyjointsandlinks.Itsgeometryisrepresentedbyasetofconnectedlimbs(Figure1).Thisdescriptionisadequatetobeusedinamotioncaptureani-mationsystem,sinceitre ectsthestructureofanarticulated gure.Fordataacquisition,markersareattachedatthejointsofaliveperformer(thereal

actor).Figure1:Topologicalandgeometricaldescriptionofanactorusedinthesystem.Attheprogramminglevel,theactorisrepresentedusingamodi edversionofZeltzer’sAPJ(AxisPositionJoint)structure[3],adaptedtoworkwithmotioncaptureddata.

Motionsarebestrepresentedascurvesintime(Figure

2).

Figure2:Examplesofjointmotioncurves.

Abstract. This paper proposes a new user interface paradigm for motion capture based animation systems, providing intuitive and efficient ways to visualize the main motion capture concepts and operations. A prototype system was built, implementing the prop

Normally,thecaptureddataconsistsofmarker’spositionaland/orangularvariation,sampledbythecapturehardwareduringthenumberofframesre-quiredtocompletetheactor’sperformance.Thisdescriptionisusedineachdegreeoffreedom(DOF)oftheactor.

Internally,theinteractionwiththeuseriscontrolledbyadynamicdatastructurethatrepresentsthecurrent“state”ofallwindowsandmaindatastructuresexistinginthesystem.

2.2AnArchitectureFocusedonMotionCapture

Wedevelopedaconceptualarchitecture,designedtoworkwiththemotioncap-tureparadigm.Itfocusesonsometechnologicalaspectsandembodiesseveraltechniquestodealwithcaptureddata,thusallowingthecreationofreusablemotionlibrariesbyusingabuildingblockparadigm.

Theframeworkofthearchitecture(Figure3)isformedbythreebasicmodules(input,processingandoutput),eachoneresponsibleforaspeci csetoftasks.Thedatastructuresusedinthesystemweredescribedin2.1.

Figure3:System’sarchitecture.

Allmodulesaresupportedbytheconceptualinterfacethatwillbedescribedinsection3.Foramoredetaileddescriptionofsystem’sarchitecture,pleasereferto[4].

InputModule

Theinputmodulefocusesonproblemsconcerningtheinterpretationandpre-processingofmotiondata.Skeletonde nition leswerecreatedtoestablishrelationshipsbetweentheskeletonexpectedbytheincomingdata1andarchi-tecture’sinternaldefaultskeletonde nition.Also,geometricalalgorithmsfor1Dependingonthemotiondataformat.

Abstract. This paper proposes a new user interface paradigm for motion capture based animation systems, providing intuitive and efficient ways to visualize the main motion capture concepts and operations. A prototype system was built, implementing the prop

3DEulerangleextraction2,pre- lteringandhierarchicalanglegenerationareprovidedinthismodule.

ProcessingModule

Theprocessingmodulecomprisesthesetoftoolsformotionanalysis,manip-ulationandreuse.Threebasicmotionoperationtypesarede ned: ltering;concatenation;andblending.Theirobjectiveistoprovidee cientwaystomodifytheoriginalcaptureddata.Withthesetools,theuserisabletogeneratenewclassesofmotions,inheritingthealivenessandcomplexitytypicalofnaturalmotion.

Filteringoperationscanbeappliedtothejointcurvesofamotion,toreducenoiseorevenmodifyspeci ccomponentsofthemovement.In[9],Williamsusedamultiresolution lteringapproachtodecomposethemotioninfrequencybands,thusallowingmodi cationsinahigherlevelofabstraction.

Withconcatenationoperations,longeranimationscanbeproducedbycombiningseveralmotionsinsequence.Smoothtransitionsbetweenthecombinedmotionscanbeproducedusingalgorithmsbasedonblendingofmotionparameters[4].Spacetimeconstraints[12]canalsobeusedtogenerateseamlessanddynamicallyplausibletransitions,withexcellentresults.

Blendingoperationsarenormallyusedtocombinespecialcharacteristicsofdif-ferentmotions.Inthiscase,theexistenceoftoolsformotionsynchronizationandreparametrizationisveryimportanttohelpintheblendingprocess,ensuringacoherentresult.

OutputModule

Themainobjectiveofthismoduleistoprovidewaystostorethecompositioncreatedbytheuser,thusmaintainingandexpandingtheexistingmotionlibrary.Auniversaldataformatwasde ned,embodyingthemaincharacteristicsofmostmotiondataformatsavailablenowadays.Consequently,thesystemcanbeusedasarobustconversortomotioncapturedataformats.

UserInterface

Theuserinterfaceusedinthesystemisbasedonavisualrepresentationofmotioncapturebasicconcepts,suchasmotionsandoperations.

Webelievethatitisalsointerestingtosupplyanon-graphicalusercommunica-tion,usingaexpressionlanguagethatrepresentsalltheactionsthatwouldbedoneusingthegraphicaldescriptionprovidedintheuserinterface.

2Inthecaseofdatawithpositionalinformationonly.

Abstract. This paper proposes a new user interface paradigm for motion capture based animation systems, providing intuitive and efficient ways to visualize the main motion capture concepts and operations. A prototype system was built, implementing the prop

Wearecurrentlyworkingonaexpressionlanguagesimilartothatdescribedin[12].Usingthislanguage,theuserwillbeabletogeneratecomplexanimationswithmotionoperations,usingcommandsthatwillactuallyexecutethecallbackfunctionssupportingtheuserinterface.Thesecommandsmaybestoredinatext leandcanbereusedoredited.

Control

Acontinuousloop(Figure4)veri esthestatusofallinterfaceobjectsandwin-dows,reportinganychangestoaspecialfunctionthatmanagesthosechangesthatactuallymustbedoneduetouserinteraction.

Figure4:Userinterfacecontrolwithastatecheckingloop.

3AGraphicInterfaceforMotionCapture

Asdiscussedbefore,oursystemisbasedonanarchitecturethattreatstheproblemofdealingwithcapturedmotions.However,thefunctionalityofitsarchitecturewouldbeshadowedbytheconventionaluserinterfaceparadigmusedonmostanimationsystemscurrentlyavailable.

Ourgoalistodescribethebasicstructuresofthesystem’sarchitectureinaconciseway,providingpowerfulinterfacetoolsthatwillmakeiteasiertoexecutemotioneditingoperations.Moreover,thisinterfacemustbeextensible,allowingtheincorporationofnewoperationsandtechniques.

Wenotedthateachcapturedmotionispotentiallyareadyanimation,andthereforemustbetreatedaccordingly.Thispromptedustoadoptaninterfaceparadigmusedinsomepost-productionvideoworkstations[10]asastartingpointtoourwork.

Abstract. This paper proposes a new user interface paradigm for motion capture based animation systems, providing intuitive and efficient ways to visualize the main motion capture concepts and operations. A prototype system was built, implementing the prop

Inthefollowingsub-sections,wewilldescribethemaininterfaceobjectsandconceptsdevelopedundertheproposedmethodology.Allimagespresentedinthissectionareactualscreenshotsoftheprototypesystem,whichimplementstheconceptsdescribedinthispaper.

3.1Actor

Inourinterfaceparadigm,theactorisvisualizedbymeansofitscomponents:theskeletontopologyandgeometry.Theskeletonstructureisshowninawin-dowasagraphcomposedofjointsandlinks(Figure5).Thiswindowdisplaysinformationabouteachjointandthelinksbetweenthem.Theinterfaceallowsjointselectionand/or

grouping.

Figure5:Skeletongraphwindow.

Therepresentationoftheactorcanbevisualizedwithdi erentstylesintherenderingwindow,asshowninFigure6.Theselectedjointinthegraphwindowappearsindi erentcolorandsizeintherenderingwindow.Thisselectionalsoa ectsotherinterfaceobjects,aswillbediscussedlater.

Abstract. This paper proposes a new user interface paradigm for motion capture based animation systems, providing intuitive and efficient ways to visualize the main motion capture concepts and operations. A prototype system was built, implementing the prop

Figure6:Jointselection(detailfromskeletongraphwindow)andvisualfeedbackintherenderingwindow.

3.2Motions

Inthepost-productionvideointerfacemodel,videoandsoundsequencesarevisualizedashorizontalbars,whichcanbegrouped,positionedandcombinedinatimelinecanvas,inordertoproducethe nalcomposition.

Inourparadigm,wetreatamotionasahorizontalbar(Figure7),whosewidthisdeterminedbythenumberofframesofthecapturedmotion.Thisbaralsocontainsinformationaboutthemotionname.Notethearrowmarkerattherightendofthemotionbar,whichindicatesthatmotionresizing(reparametrization)is

allowed.

Figure7:MotionrepresentationasaGUIobject.

Wewillusuallyvisualizethemotionbarusingaframerulerassociatedwithit.Thisgivesamoreaccuratetemporalperceptionofthemotion.

TheMotionScratchPad

Abstract. This paper proposes a new user interface paradigm for motion capture based animation systems, providing intuitive and efficient ways to visualize the main motion capture concepts and operations. A prototype system was built, implementing the prop

Inoursystem,wehavecreatedaninterfaceobjectwhosepurposeistoactasamotionorganizer,providingaglobalperceptionofallmotionsplacedonit.WecalledthisobjecttheMotionScratchPad(Figure

8).

Figure8:MotionScratchPad-themotionorganizer.

UsingtheScratchPad,theusercanchooseseveralmotionsandorganizethemintheobjectcanvas.Allmotionscanbeindividuallyplayedorresized,andtheusercandropthemtothemotionoperations.TheScratchPadisactuallythegatewaybetweentheinputandtheprocessingmodules.

TheScratchPadisthecontainerwheremotionfragmentsarestored,waitingtobeused.

JointCurves

Jointcurvesarethebasiccomponentsofmotion.Theyarevisuallyrepresentedbyaninterfaceobjectthatdisplayscurveshape.Italsoprovidesnumericin-formationaboutthedi erentdatachannelsateachframe(i.e.,threepositionandorientationvalues,foreachjointcurve).ThevisualrepresentationofajointcurveisshowninFigure9.

Withthisrepresentation,itisstraightforwardtoimplementseveralcurveeditingtechniques[9][11],allowingapreciseandinteractivecontrolofthecurveshape.Foreachjointoftheactor,theremaybeseveraljointcurves(oneforeachDOF)attachedtoit.Thesecurvesaregroupedinainterfaceobject,theJointCurvesWindow,thato ersaglobalviewofthecurves,andhasadirectconnectionwiththeskeletongraphwindow.Whenajointisselectedinthegraphwindow,itscurvesaredisplayedandusefulinformationisprovided,asshowninFigure10.

Abstract. This paper proposes a new user interface paradigm for motion capture based animation systems, providing intuitive and efficient ways to visualize the main motion capture concepts and operations. A prototype system was built, implementing the prop

Figure9:Visualrepresentationofajoint

curve.

Figure10:JointCurvesWindow.

TheMotionWindow

Finally,wedecidedtocreateaninterfaceobjectthatactsasaconnectionbe-tweenmotionandactordescriptions.TheMotionWindow(Figure11)isac-cessedviaadouble-clickinamotionbar,andallowstheselection(orgrouping)ofspeci cjointsoftheactor.

TheMotionWindowiscomposedofseveralbars,eachonerepresentinganactorjoint(detailinFigure11).Visually,itlookslikeazoominthemotionbar.Thisrepresentationisintentional,sincethemotionisformedbythecurvesthatareattachedtoactor’sjoints.

TheMotionWindowwillproofitsutilitywhenusedinconjunctionwithmotionoperations,allowingtheapplicationofanoperationtoaspeci csetofjointsoftheactor.

Abstract. This paper proposes a new user interface paradigm for motion capture based animation systems, providing intuitive and efficient ways to visualize the main motion capture concepts and operations. A prototype system was built, implementing the prop

Figure11:MotionWindow-connectingactorandmotiondescriptions.

3.3MotionOperations

Motionoperationsarethemostimportantobjectsinthearchitecture.Therefore,theymustbevisualizedinawaythatmakestheprocessintuitivetotheuser.Inourinterfaceparadigm,eachmotionoperationhasitsownwindow.Whenrequested,additionalobjectsareusedtohelpintheprocess,providingafullcontroloftheoperationparameters.

Allmotionoperationwindowshaveabasicsetofauxiliaryobjects:aninteractiveplayersliderandaframeruler.Theseobjectsalsofollowtheinterfaceconceptsdescribedearlier.

Filtering

The lteringoperation(Figure12)isrepresentedinawindowwithtoolswhichallowtheselectionofaspeci cregionofthemotiontobe ltered(andwithalistoftheexisting lters,whichcanbeaccessedbypressing Concatenation

Abstract. This paper proposes a new user interface paradigm for motion capture based animation systems, providing intuitive and efficient ways to visualize the main motion capture concepts and operations. A prototype system was built, implementing the prop

Figure12:Filteringoperationwindow.

Theinterfaceobjectthatrepresentstheconcatenationoperationwasdesignedtoprovideagoodvisualperceptionofthecompositionasawhole.

ThemotionsselectedbytheuserintheScratchPadaredroppedintotheCon-catenationWindow.Initially,theyarepositionedinsuchawaytoperformadirectconcatenation(i.e.,withoutblendinginterval),asshowninFigure

13.

Figure13:Concatenationoperationwindow(initialmotionarrangement).

Usingtheexistingtoolsformotionpositioningandreparametrization,theusercande neblendingintervalsthatwillpermitasmoothtransitionbetweenthecombinedmotions(inFigure14,representedbythedarkerregionsbetweenmotions).

However,someinterfaceconstraintswerecreatedtoavoidundesirableresults.Theseconstraintsensurevisualcoherence,andguidetheuserintheoperationprocess.

Abstract. This paper proposes a new user interface paradigm for motion capture based animation systems, providing intuitive and efficient ways to visualize the main motion capture concepts and operations. A prototype system was built, implementing the prop

Thedefaulteasy-in/easy-outblendingparameterscanbemodi edbydouble-clickinginthedesiredblendingintervaloftheConcatenation

Window.

Figure14:Blendingintervals(detailfromConcatenationWindow).

Blending

Blendingisthelasttypeofmotionoperationde nedintheprimarysetoftheprototypesystem.

AsintheConcatenationWindow,allmotionsselectedbytheuserareplacedinacanvas,providingaglobalviewoftheoperation.Forblending,however,newobjectswereintroducedtoassistinthespeci cation.

Thesenewobjectsarethetime-markers,andtheirpurposeistosynchronizekeypointsinthecombinedmotions.Forexample,whencombiningtwodi erenttypesofwalkmovements,itisdesirablethatthefeetreachthegroundatthesameinstantinbothmotions,otherwisestrangeresultscanbeproduced.

Figure15showsasnapshotofablendingoperationbetweenthreedi erentmotions.Thetime-markers(detailfromFigure15)wereusedtoestablishacorrespondencebetweenthekeystepsinthecombinedmotions.

Thissynchronizationprocesswillreparametrizethemotionsaccordingtothepositionofthetime-markers,matchingtheiroccurrenceintime.Todothat,algorithmsbasedontimewarpingareused.Agoodexamplecanbefoundin[9].

3.4Higher-LevelInterfaceObjects

Tocompletetheinterfacedescription,wepresentotherobjectsthatareimpor-tanttocreateapowerfulanimationenvironment.

Abstract. This paper proposes a new user interface paradigm for motion capture based animation systems, providing intuitive and efficient ways to visualize the main motion capture concepts and operations. A prototype system was built, implementing the prop

Figure15:Blendingwindowwithtime-markers(indetail).

CameraControls

Oursystemprovidesseveraltoolsforcameracontrol.InFigure16,wepresenttheCameraControlWindow,withsomeoptionsthatallowaprecisecontrolofvariouscamerasettings.

Amongtheseoptions,probablythemostusefulonesare:thefollowmode-whichguidesautomaticallythecamerathroughoutthescene,followingtherootjointthatdrivestheskeletonhierarchy;thelockjointmode-whichpointsthecameratargettotheactivejoint,selectedintheskeletongraphwindow;andthecirclecameraoption,whichallowsaninteractivecircularmovementofthecameraovertheactivejoint,whiletheanimationisbeingplayed.

Moreover,thesecameraoptionscanbemixed,thusgivingayetmoreprecisecontrolofthecameramotion.

Additionalcontrolsforscenelightingarealsoprovidedwiththe

system.Figure16:Cameracontrols.Fromtoptobottom:Zoomin,Zoomout,Followmode,LockJointmode,Circlecamera

Abstract. This paper proposes a new user interface paradigm for motion capture based animation systems, providing intuitive and efficient ways to visualize the main motion capture concepts and operations. A prototype system was built, implementing the prop

PlaybackControls

Followingthepost-productionvideointerface,wedevelopedacontrolpanel,whichallowsinteractivecontrolofanimationsinoursystem(Figure

17).

Figure17:Playbackandrenderingwindows.

TheplaybackofmotionsorcompositionsproduceduserareexecutedinadedicatedOpenGLrenderingwindow(inFigure17,Thecontrolpanelisintegratedwithit(inFigure17,),supplyingasetofcontrolssimilartothoseusedinvideorecorders.

ObjectsforOtherAnimationTools

Asdiscussedbefore,thearchitectureusedinthesystemallowstheintegrationofotheranimationtechniqueslikekeyframing,forwardandinversekinematicstohelpintheprocessingofcapturedmotions.

Inthecurrentimplementation,thesystemusesforwardkinematicsasanauxil-iarytooltoadjustthepositionofspeci cjointswhennecessary.Theadditionofkeyframingandinversekinematictoolsisplannedforfutureimplementations.

3.5ImplementationIssues

ThepresentedinterfaceparadigmandprototypesystemwereimplementedintheprogramminglanguageC,usingaSGIIndigo2graphicworkstationasthebaseplatform.WeemployedOpenGL[14]forrenderingandXForms[13]for

Abstract. This paper proposes a new user interface paradigm for motion capture based animation systems, providing intuitive and efficient ways to visualize the main motion capture concepts and operations. A prototype system was built, implementing the prop

GUIgeneration.TheadvancedGUIobjectsweredesignedandimplementedseparately,andthenaddedtotheFormslibrary.

DuetoOpenGL’srenderingfacilitiesandtothedynamicinterfacecontrolusedinthesystem,areal-timeframerateisachievedduringtheplaybackofanimations(about15frames/secinaSGIIndigo2).TheprototypesystemwasalsotestedintheLinuxandRISC6000platforms,alsowithgoodframerates.

Figure18showsasnapshotofatypicalsystemusage,withanarrangementcontainsomeofthepreviousdescribedwindows(JointCurvesWindow,SkeletonGraphWindow,MotionScratchPad

Window,ConcatenationWindow,andPlaybackandRenderingWindow,).

Figure18:Snapshotoftheprototypesystem.

4Conclusions

Inthispaper,wehaveproposedanewuserinterfaceparadigmformotioncap-turebasedanimationsystems.Aprototypesystemwasbuilt,employingthepresentedinterfaceconceptsandsupportedbyapowerfularchitecturedesignedtoworkwiththemotioncapturemethodology.

Theimplementedsystemhasprovedtobeeasyandintuitivetouse,withpromis-

Abstract. This paper proposes a new user interface paradigm for motion capture based animation systems, providing intuitive and efficient ways to visualize the main motion capture concepts and operations. A prototype system was built, implementing the prop

ingresultsthatencourageustoimproveitevenmore,withfeatureslike:

implementationofotheradvancedmotionoperations([9],[11],[12]),com-paringtheirresultsandextractingconclusionsandsuggestionsforimprove-mentsand/ornewtechniques.Inthiscase,thesystemwillserveasatestbedfornewmotioncaptureprocessingtechniques.

insertionofprocedural[15]andbehavioral[18]animation“plug-ins”inthesystem.Inthe rstcase,capturedmotionscouldactasaregentfactor,guidingtheproceduralobjects.Inthesecondcase,thebehavioralfunctionscouldcontroltheprocessingmodule,combiningandmodifyingcapturedmotionstoimprovethevisualqualityoftheanimations.

combinationofmotioncapturewithsound.Inthiscase,thetime-markerscouldbeusedtosynchronizethekeymomentsinthemotionwiththetem-poraldescriptionofthesound.

5Acknowledgements

TheauthorswouldliketothankViewpointDatalabs,Inc.andBiovision,Inc.foraccesstomotioncapturedata,andtotheBrazilianCouncilforScienti candTechnologicaldevelopment(CNPq)forthe nancialsupport.ThisresearchhasbeendevelopedinthelaboratoryofVISGRAFprojectatIMPAandatLCG/UFRJ,aspartoftheMasterprogrameeofthe rstauthor.ThisprojectissponsoredbyCNPq,FAPERJ,FINEPandIBMBrasil.Alsothanksareduetothereviewersfortheirvaluablecomments.

6References

[1]Ginsberg,C.M.,HumanBodyMotionasInputtoanAnimatedGraphicalDisplay.MasterThesis,MassachusettsInstituteofTechnology,May1983.

[2]Maxwell,D.R.,GraphicalMarionette:AModerndayPinocchio.MasterThesis,MassachusettsInstituteofTechnology,June1983.

[3]Zeltzer,D.andSims,F.,AFigureEditorandGaitControllerforTaskLevelAnimation.InComputerGraphics(SIGGRAPH’88),CourseNotes,no.4,164-181.

[4]Silva,F.,Velho,L.,Cavalcanti,P.andGomes,J.M.,AnArchi-tectureforMotionCaptureBasedAnimation.(preprint),1997.

[5]Dyer,S.,Martin,J.andZulauf,J.,MotionCaptureWhitePaper.TechnicalReport.SiliconGraphics,December12,1995.

[6]CharacterMotionSystems.InComputerGraphics(SIGGRAPH’94),Courseno.9.

Abstract. This paper proposes a new user interface paradigm for motion capture based animation systems, providing intuitive and efficient ways to visualize the main motion capture concepts and operations. A prototype system was built, implementing the prop

[7]Mulder,S.,HumanMovementTrackingTechnology.HandCenteredStudiesofHumanMovementProject,SimonFraserUniversity.TechnicalReport94-1,July1994.

[8]O’Rourke,J.,ComputationalGeometryinC.CambridgeUniversityPress,1994.

[9]Williams,L.andBrudelin,A.,MotionSignalProcessing.InComputerGraphics(SIGGRAPH’95Proceedings)(August1995),pp.97-104.

[10]TurboCube/VideoCube-User’sGuide.IMIXCompany.

[11]Witkin,A.andPopovic,Z.,MotionWarping.InComputerGraphics(SIGGRAPH’95Proceedings)(August1995),pp.105-108.

[12]Cohen,M.,Rose,C.,Guenter,B.andBodenheimer,B.,E cientGenerationofMotionTransitionsUsingSpacetimeConstraints.InCom-puterGraphics(SIGGRAPH’96Proceedings)(August1996),pp.147-154.

[13]XformsHomePage,http://bragg.phys.uwm.edu/xform

[14]Neider,J.,Davis,T.andWoo,M.,OpenGLProgrammingGuide-TheO cialGuidetoLearningOpenGL,Release1.Addison-Wesley,1993.

[15]Perlin,K.,RealtimeResponsiveAnimationwithPersonality.InIEEETransactionsonVisualizationandComputerGraphics,Vol1,No.1,March1995.

[16]Witkin,A.andKass,M.,SpacetimeConstraints.InComputerGraphics(SIGGRAPH’88Proceedings)(August1988),pp.159-168.

[17]Terzopoulos,D.etal.,Arti cialFisheswithAutonomousLocomotion,Perception,BehaviorandLearning,inaPhysicalWorld.InProceedingsoftheArti cialLifeIVWorkshop,MITPress(1994).

´,B.,AnArchitectureforConcurrentReactiveAgents[18]Costa,M.andFeijoinReal-TimeAnimation.InProceedingsofSIBGRAPI’96,IXBrazilianSymposiumofComputerGraphicsandImageProcessing,pp.281-288.1996.

本文来源：https://www.bwwdw.com/article/dy11.html