Motion Capture Readings

by Mike Gleicher on February 3, 2011 · 3 comments

in Readings

This is a big long file with lots of ideas in it – specific readings will probably get clipped out of this.

If you notice, I have no good readings for the basic stuff. Back in 2000, I started to write a book, but I didn’t get very far. No one else did it either.

General Mocap Readings

I am surprised that I have nothing that is more up-to-date and good. Here are two old things (written 2000 or before) – its interesting to think about what has (and hasn’t). And since these viewpoints are (were?) mine, you can see how far we’ve come. For historical context: when these were written, motion graphs hadn’t been invented (although their pre-cursors were already in use in the games industry.

Another “philosophy” paper I wrote much later.

Overviews of Motion Capture Techniques

There have been several decent survey papers that describe the range of “modern” motion synthesis/processing techniques.

Overview of the Basic Ideas in motion processing:

Again, a chapter from that never-written book. Remember, this was 2000, and I didn’t understand Quaternions at all. Also, spacetime constraints were my thing (skip that section).

The “original” sources where these ideas were introduced

  • Motion Signal Processing
    by Armin Brudelin and Lance Williams, SIGGRAPH ’95

  • Motion Warping
    by Zoran Popovic and Andrew Witkin, SIGGRAPH ’95

Two historically significant systems that used blending techniques before they were really made widely known.

  • Real Time Responsive Animation with Personality
    by Ken Perlin, IEEE TVCG (Trans on Visualization and Comp Graphics), 1995 (Vol 1, Issue 1)

  • Verbs and Adverbs: Multidimensional Motion Interpolation
    by Charles Rose, Michael F. Cohen, and Bobby Bodenheimer, IEEE Computer Graphics and Applications (CG&A), September 1998.

An Alternative to the “usual” (skeletal) methods

From time to time, people (including me) talk about alternatives to skeletons. There are pros and cons to them, but we seem to just take them as a given. The group at Rennes (Richard Kulpa, Franck Multon, …) are the main group I know that have really tried this extensively. I’m not sure about the details – they make some decisions that I am not sure of (and I’ve talked to them about it), but if nothing else its interesting to see someone exploring an alternative to the conventional wisdom. Even things like dynamic time warping are re-thought (this is a place where I think better methods exist). Anyway, I think its good to look at this for food for thought. This group of people have been very successful at using this framework (see Richard’s publication page for some really interesting applications).

  • Multon, F., Kulpa, R. & Bideau, B. MKM: a global framework for animating humans in virtual reality applications. Presence: Teleoper. Virtual Environ., 2008, Vol. 17(1), pp. 17-28 – Abstract Pdf BibTeX
    (this is a systems paper, giving an overview of everything together)
  • Kulpa, R., Multon, F. & Arnaldi, B. Morphology-independent representation of motions for interactive human-like animation. Computer Graphics Forum, Eurographics 2005 special issue, 2005, Vol. 24(3), pp. 343-352 – Abstract Pdf BibTeX
    (this is the paper with the representation details and retargeting method)

This one is very different, but again, chooses a non-standard representation for the motion.

  • Edmond S.L. Ho, Taku Komura, and Chiew-Lan Tai.  Spatial Relationship Preserving Character Motion Adaptation. SIGGRAPH 2010 (ACM Trans Graph 29(4)). (project page w/PDF and video). Although, if you’re on campus, it might be best to get the ACM Digital Library version (here).

Inverse Kinematics

Again, this is such a basic topic that I am surprised that I don’t have a good tutorial.

This seminal paper is one that really starts to get at core issues with numerical methods

  • Dealing with the Ill-Conditioned Equations of Motion for Articulated Figures
    Anthony Maciejewski in IEEE CG&A, May 1990
    Note: this paper is valuable not just because it describes a method for doing IK, but also the geometric and numerical issues involved.
    http://dx.doi.org/10.1109/38.55154
    (local pdf) 

Here are two very practical papers for the special cases of limbs.

Here’s a tutorial on some of the commonly used numerical methods.

And a fancier method that adds a few very useful features.

  • Paolo Baerlocher and Ronan Boulic. An Inverse Kinematic Architecture Enforcing an
    Arbitrary Number of Strict Priority Levels. The Visual Computer – VC , vol. 20, no. 6, pp. 402-417, 2004. (pdf)

This is a newer paper that extends some of the methods above:

  • Marcelo Kallmann. Analytical inverse kinematics with body posture control. Computer Animation and Virtual Worlds, 19 (2) May 2008. (ACM DL) (found pdf)

Inverse Kinematics by Example

A newer way to solve IK problems is to use a database of examples. This was pioneered by Rose et al, had complicated machine learning math thrown at it, and most recently huge databases.

Motion Graphs

Motion graphs were introduced by 3 papers simultaneously. There were prior papers that had similar ideas, and many systems used graphs (albeit manually constructed and simply accessed). But these 3 papers are generally considered the beginning of “modern” graph-based techniques.

I like ours best in terms of explaining things, although, the others had more clever search algorithms. Over time, all those elements were enhanced.

Old School Spacetime Editing

When we talk about IK, a question will come up as to how to apply it to motions (rather than individual frames). In class, I’ll talk about some “historical approaches.” You might want to look at these papers to better understand them.

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