基於编辑主要关节动线之动作合成法(精)

基於編輯主要關節動線之動作合成法在電腦動畫的研究領域中，動作合成(MotionSynthesis)一直是3D電腦動畫中非常重要的研究課題。在本論文中，我們提出了一個藉編輯人體主要關節在空間中運動軌跡來合成三維人體動作的方法以及相關應用之介面設計。盧奕丞、劉庠宏、黃科森、楊熙年國立清華大學Outline•Introduction•RelatedWork•SystemOverview•Demonstration•ConclusionIntroduction•Characteranimationshavebeenwidelyusedinmoviesandgames.•Itisstillachallengingtaskforartiststogeneratehighqualitymotions.•Mocapsystemisdifficulttoreuse.•Increasingdemandforuser-friendlytoolsforthree-dimensionalanimations.Hand-drawnAnimationsIntroduction•Providinganinterfaceforartiststocreate3Dhumanmotion.•UsingInverseKinematicstocomputejointangles.•UsingB-SplineCurvestorepresentjointtrajectories.•ExploitingOptimizationmethodtofinetunethesynthesizedmotioncurves.Introduction•3Dtrajectoriesarehardtosketchorcreate.•Incontrast,2Dtrajectoriescanbeeasilycreatedwithamouseortouchpad.•TrajectoriesofKey-Joints:–root,head,–leftwrist,rightwrist,–leftankle,rightankleIntroduction•B-splineinterpolationisusedtosynthesissmoothtrajectories.•Oncethepositionsofendjointsaredetermined,InverseKinematicscanbeappliedtocalculateotherjoints.•Optimizingmotionquality.RelatedWork•HumanMotionCreation－Keyframe&Interpolation－Procedure－MotionCaptureRelatedWork•HumanMotionControl－Dynamics:“PhysicallyBasedMotionTransformation”byPopovicandWitkin’s(1999).－Kinematics“Three-DimensionalHumanRunning”byHodgins,J.K.,(1996).TemplateSkeleton•15joints•IKchain1:root-throat-head•IKchain2&3:shoulder-elbow-hand•IKchain4&5:hip-joint-knee-footComponents•UserInput:－skeletonfile(*.asf)－motionfileforinitialpose(*.asm)－timelengthofmotion.－samplepointsofjointstrajectories.Components•B-SplineManager－B-splinecurvesfittingtosamplepoints.－returnspositionsofendjoints.－editstrajectoriesofjoints.•InverseKinematicsComputer－convertsasffiletodhfile.－useinversekinematicstocomputerotationanglesofnon-endjoints.Components•MotionOptimizer－optimizesthemotionfromI.K.•SystemOutput－amotionplayerformotionviewing.－savesthecomputedmotion.ManipulationandProcessing•Loadsa3Dtemplateskeleton.•Specifiestimelength.•Draws2Dtrajectoriesofkeyjoints.•Editstrajectories.•Previewsthemotion.•Savesthemotion.RefinementbyOptimization•Theproblemswithcomputedmotioncurves.–Constraintsonjointangles.–Constraintsonend-effectors’position.–Constraintsonlimblength.•Refiningthecurvesbyoptimization.RefinementbyOptimization•Notation:•Vectortobeoptimized:),,(jfjfjfjfZYXp][1211jfppppRefinementbyOptimization•FrameCoherence:•JointAnglesConstraint:2)1(2)1(fjjffjjfpppp2naturaljfRefinementbyOptimization•LimbLengthConstraint:•End-Effectors'Constraint:2kfjfbppl22)()(jfjfjfjfyYxXRefinementbyOptimization•Z-coordinateCoherence:when)1()1(,,,,fjfjjfjfkfkfjfjfYXYXYXYX22(1)jfkfjfjfZZZZRefinementbyOptimization•Solvethefollowingobjectives:•End-Effectorsweightsaregreaterthanotherjoints’weights.iiipTwminargImplementation•C#&WindowsForm•MicrosoftVisualStudio2005•ManagedDirectX9.0c(Render)•RRGKinematix(InverseKinematics)•WildMagic4(B-Spline)•EngMATLib(connectionbetweenc#&MATLAB)•MATLAB2007a(Optimization)ResultsDemonstrationConclusion•Themethodforcreatingthree-dimensionalhumanmotionispresentedbasedonsketchingtwo-dimensionaltrajectoriesofKey-joints.•Userscanspecifytheirexpectedmotionbysketching2Dtrajectoriesofprojectedjoints.Conclusion•Auser-friendlyinterfaceisdevisedforconvenience.•Optimizationtechniqueisusedtoguaranteethequalityofsynthesizedmotioncurves.Q&A•Thankyou