This paperpresentsa techniquefor adaptingexisting motion of a human-likecharacterto have thedesiredfeaturesthatarespecified by asetof constraints.Thisproblemcanbetypically formulatedas a spacetimeconstraintproblem. Our approachcombinesa hierarchicalcurvefitting techniquewith anew inversekinematicssolver. Usingthekinematicssolver, we canadjusttheconfigurationof an articulatedfigure to meetthe constraintsin eachframe. Through thefitting technique,themotiondisplacement of every joint ateach constrainedframeis interpolatedandthussmoothlypropagatedto frames.We areableto adapti vely addmotiondetailsto satisfythe constraintswithin aspecifiedtoleranceby adoptingamultilevel Bsplinerepresentationwhich alsoprovidesa speedupfor the interpolation. The performanceof our systemis further enhancedby thenew inversekinematicssolver. We presenta closed-formsolution to computethe joint anglesof a limb linkage. This analytical methodgreatlyreducesthe burdenof a numericaloptimizationto find thesolutionsfor full degreesof freedomof ahuman-likearticulatedfigure.Wedemonstratethatthetechniquecanbeusedfor retargettinga motion to compensatefor geometricvariationscaused by both charactersand environments. Furthermore,we can also usethis techniquefor directly manipulatinga motionclip through agraphicalinterface. CR Categories: I.3.7 [Computer Graphics]: ThreedimensionalGraphics—Animation;G.1.2 [Numerical Analysis]: Approximation—Splineandpiecewisepolynomialapproximation
[1]
Anthony A. Maciejewski,et al.
Computational modeling for the computer animation of legged figures
,
1985,
SIGGRAPH.
[2]
Francis J. M. Schmitt,et al.
An adaptive subdivision method for surface-fitting from sampled data
,
1986,
SIGGRAPH.
[3]
William H. Press,et al.
Numerical recipes in C (2nd ed.): the art of scientific computing
,
1992
.
[4]
John F. Hughes,et al.
Direct manipulation of free-form deformations
,
1992,
SIGGRAPH.
[5]
David Salesin,et al.
Multiresolution curves
,
1994,
SIGGRAPH.
[6]
Tony DeRose,et al.
Multiresolution analysis of arbitrary meshes
,
1995,
SIGGRAPH.
[7]
Zoran Popovic,et al.
Motion warping
,
1995,
SIGGRAPH.
[8]
Sung Yong Shin,et al.
A general construction scheme for unit quaternion curves with simple high order derivatives
,
1995,
SIGGRAPH.
[9]
Lance Williams,et al.
Motion signal processing
,
1995,
SIGGRAPH.
[10]
Sung Yong Shin,et al.
Scattered Data Interpolation with Multilevel B-Splines
,
1997,
IEEE Trans. Vis. Comput. Graph..
[11]
Michael Gleicher,et al.
Motion editing with spacetime constraints
,
1997,
SI3D.
[12]
Tony DeRose,et al.
Multiresolution analysis for surfaces of arbitrary topological type
,
1997,
TOGS.