【正文】 Can create long and novel “streams” (keep putting clips together) ? Challenges: 187。 Popovic 95] Motion Signal Processing MOTION PLANNING IN REAL AND VIRTUAL ENVIRONMENTS FALL 2022 Manipulating motion ? Manipulate time 187。 Use the best one for the job Motion Representation MOTION PLANNING IN REAL AND VIRTUAL ENVIRONMENTS FALL 2022 Goals for Parameterization ? Compact 187。 positions of markers are recorded ? retarget motion on a virtual character 187。 Everquest II 187。 marker crossover, which marker are you looking at? 187。 no built in positional reference ? disadvantages 187。 David J Sturman, “A Brief History of Motion Capture for Computer Character Animation”, Character Motion Systems, SIGGRAPH 94, Course 9 “The creation of a 3d representation of a live performance” 187。 portable, unlimited range 187。 high quality capture 187。 Spider Man ? Games 187。 problem: occlusion, marker is not seen ? use more cameras ? markers need to be labeled 187。 Usually TPose ? Rigid pieces undergo rigid transformation ? Hierarchical representation of the configuration Motion Representation MOTION PLANNING IN REAL AND VIRTUAL ENVIRONMENTS FALL 2022 Computing positions ? Each joint i provides a local rotation Ri and a local translation Ti. Concatenating Ri and Ti gives local Mi, the local transform at each joint. ? The transformation of the point x on joint j is found by concatenating all previous transforms in the hierarchy as follows: Motion Representation MOTION PLANNING IN REAL AND VIRTUAL ENVIRONMENTS FALL 2022 Parameterizing Rotations ? Goal: encode rotations in a vector 187。 But we don?t know what to preserve 187。 Need motion capture (examples) ? Flexible, longrunning, controllable 187。 Blends between aligned motions 187。 F : Rn Rn 187。 Every rotation has one value 187。 need rotation data! ? need to convert positions to rotations Mocap Overview MOTION PLANNING IN REAL AND VIRTUAL ENVIRONMENTS FALL 2022 performer→ actor → character ? the actor is used to convert marker positions to rotational data 187。 no occlusion ? disadvantages 187。 Lord of the Rings 187。 transmitters are attached to the performer and sequentially emit audio signal, a “click” ? receivers measure the time to receive the signal, triangulate and pute the position of the transmitter ? advantages 187。 external sensors (., cameras) 187。 optic 187。 more on active markers later ? a system of cameras record the position of the markers 187。 Polar Express 187。 which motions transition into which other transitions 187。 Rigid pieces 187。 m(t): R Rn ? Vectorvalued, timevarying signal Motion Signal Processing MOTION PLANNING IN REAL AND VIRTUAL ENVIRONMENTS FALL 2022 Challenge and solution ? Get a specific motion 187。 A bad pose isn?t such a big deal 187。 Random walks (screen savers) 187。 Interpolating root position – Linear interpolation 187。 Given time, provide a pose 187。 Appearance Models 187。 metal in vicinity can interfere with system 187。 Final Fantasy ? Games 187。 rate of transmission not high enough to support enough transmitters 187。 external sources 187。 magic systems ? InsideIn 187。 size of the capture area is limited 187。 NBA Live 2022 187。 capture volume can be limited Mocap Overview MOTION PLANNING IN REAL AND VIRTUAL ENVIRONMENTS FALL 2022 Mocap pipeline ? Planning for capture ? Setup and calibrate system ? Capture performer, obtain marker positions ? Retarget to a character ? Edit/cleanup Mocap Overview MOTION PLANNING IN REAL AND VIRTUAL ENVIRONMENTS FALL 2022 planning ? motion capture requires serious planning ? anticipate how the data will be used ? garbage in garbage out ? shot list ? games 187。 Facial animation 187。 m(t): R Rn ? Often represented as samples 187。 Interpolating joint rotation – SLERP (Spherical Linear intERPolation) Motion Signal Processin