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  <doc>
    <id>5452</id>
    <completedYear/>
    <publishedYear>2014</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>109:1</pageFirst>
    <pageLast>109:10</pageLast>
    <pageNumber/>
    <edition/>
    <issue>4</issue>
    <volume>33</volume>
    <type>article</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
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    <title language="eng">Animating Deformable Objects Using Sparse Spacetime Constraints</title>
    <abstract language="eng">We propose a scheme for animating deformable objects based on spacetime optimization. The main feature is that it robustly and quickly (within a few seconds) generates interesting motion from a sparse set of spacetime constraints. Providing only partial (as opposed to full) keyframes for positions and velocities is sufficient. The computed motion satisfies the constraints and the remaining degrees of freedom are determined by physical principles using elasticity and the spacetime constraints paradigm. Our modeling of the spacetime optimization problem combines dimensional reduction, modal coordinates, wiggly splines, and rotation strain warping. Controlling the warped motion requires the derivative of the warp map. We derive a representation of the derivative that can be efficiently and robustly evaluated. Our solver is based on a theorem that characterizes the solutions of the optimization problem and allows us to restrict the optimization to very low-dimensional search spaces. This treatment of the optimization problem avoids a time discretization and the resulting method can robustly deal with sparse input and wiggly motion.</abstract>
    <parentTitle language="eng">ACM Transactions on Graphics</parentTitle>
    <identifier type="doi">10.1145/2601097.2601156</identifier>
    <enrichment key="PeerReviewed">yes</enrichment>
    <author>Christian Schulz</author>
    <submitter>Christoph von Tycowicz</submitter>
    <author>Christoph von Tycowicz</author>
    <author>Hans-Peter Seidel</author>
    <author>Klaus Hildebrandt</author>
    <collection role="institutes" number="vis">Visual Data Analysis</collection>
    <collection role="institutes" number="medplan">Therapy Planning</collection>
    <collection role="persons" number="vontycowicz">Tycowicz, Christoph von</collection>
    <collection role="institutes" number="VDcC">Visual and Data-centric Computing</collection>
  </doc>
  <doc>
    <id>5487</id>
    <completedYear/>
    <publishedYear>2014</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>doctoralthesis</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>2014-05-05</thesisDateAccepted>
    <title language="eng">Concepts and Algorithms for the Deformation, Analysis, and Compression of Digital Shapes</title>
    <abstract language="eng">This thesis concerns model reduction techniques for the efficient numerical treatment&#13;
of physical systems governing the deformation behavior of geometrically complex shapes.&#13;
We present new strategies for the construction of simplified,&#13;
low-dimensional models that capture the main features of the original complex system&#13;
and are suitable for use in interactive computer graphics applications.&#13;
To demonstrate the effectiveness of the new techniques we propose frameworks&#13;
for real-time simulation and interactive deformation-based modeling&#13;
of elastic solids and shells and compare them to alternative approaches.&#13;
In addition, we investigate differential operators that are derived from&#13;
the physical models and hence can serve as alternatives to the Laplace-Beltrami&#13;
operator for applications in modal shape analysis.&#13;
Furthermore, this thesis addresses the compression of digital shapes.&#13;
In particular, we present a lossless compression scheme that is adapted to&#13;
the special characteristics of adaptively refined, hierarchical meshes.</abstract>
    <identifier type="url">http://www.diss.fu-berlin.de/diss/receive/FUDISS_thesis_000000096721</identifier>
    <identifier type="doi">10.17169/refubium-4697</identifier>
    <identifier type="urn">urn:nbn:de:kobv:188-fudissthesis000000096721-7</identifier>
    <enrichment key="FulltextUrl">http://www.diss.fu-berlin.de/diss/receive/FUDISS_thesis_000000096721</enrichment>
    <advisor>Konrad Polthier</advisor>
    <author>Christoph von Tycowicz</author>
    <submitter>Christoph von Tycowicz</submitter>
    <collection role="msc" number="53-XX">DIFFERENTIAL GEOMETRY (For differential topology, see 57Rxx. For foundational questions of differentiable manifolds, see 58Axx)</collection>
    <collection role="institutes" number="vis">Visual Data Analysis</collection>
    <collection role="persons" number="vontycowicz">Tycowicz, Christoph von</collection>
    <collection role="institutes" number="VDcC">Visual and Data-centric Computing</collection>
    <thesisGrantor>Freie Universität Berlin</thesisGrantor>
  </doc>
  <doc>
    <id>5488</id>
    <completedYear/>
    <publishedYear>2014</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>341</pageFirst>
    <pageLast>355</pageLast>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume>1</volume>
    <type>bookpart</type>
    <publisherName>EMS Publishing House</publisherName>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Geometry processing</title>
    <parentTitle language="eng">MATHEON - Mathematics for Key Technologies</parentTitle>
    <identifier type="isbn">978-3-03719-137-8</identifier>
    <identifier type="doi">10.4171/137</identifier>
    <enrichment key="Series">EMS Series in Industrial and Applied Mathematics</enrichment>
    <enrichment key="PeerReviewed">no</enrichment>
    <author>Konrad Polthier</author>
    <submitter>Christoph von Tycowicz</submitter>
    <author>Alexander Bobenko</author>
    <author>Klaus Hildebrandt</author>
    <author>Ralf Kornhuber</author>
    <author>Christoph von Tycowicz</author>
    <author>Harry Yserentant</author>
    <author>Günter M. Ziegler</author>
    <collection role="institutes" number="vis">Visual Data Analysis</collection>
    <collection role="persons" number="vontycowicz">Tycowicz, Christoph von</collection>
    <collection role="institutes" number="VDcC">Visual and Data-centric Computing</collection>
  </doc>
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