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Ioannis Ivrissimtzis
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Project descriptions
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During his visit, Ioannis has been working on the following projects:
- Recursive subdivision
Recursive subdivision is an efficient tool for the fast generation of high
quality surfaces. The basic idea is the progressive refinement of a coarse
polyhedron, by computing in each step new vertices and joining them up with
edges to form a new polyhedron. This way we create a hierarchy of polyhedra
which under certain conditions converges to a smooth limit surface. For
computing efficiency, and simplicity, the most of the known subdivision
schemes compute the new vertices as linear combinations of the existing ones.
Our research aims at developing methods to calculate the coefficients of
these linear combinations in an argued, constructive way, rather than by
solving an optimisation problem.
To do this, instead of projecting locally the polyhedron on the Euclidean
plane, we project it on a sphere or a hyperboloid, and then work out the
coefficients of the scheme taking into account the induced spherical or
hyperbolic geometry. Our methods give simple algorithms for the calculation
of the coefficients of the scheme, give new insights into well-known schemes,
and can also be used in the artifact analysis.
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Publications
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The following publications summarize some of the results of the
research work that Ioannis has participated in during his stay:
- "Geometric Analysis of Recursive Subdivision"
by Ioannis Ivrissimtzis, Mo Hassan, Malcolm Sabin, Neil Dodgson
in preparation
- "An Interpolating 4-point C2 Ternary Stationary Subdivision Scheme"
by Mo Hassan, Ioannis Ivrissimtzis, Malcolm Sabin, Neil Dodgson
in preparation
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Conferences
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Ioannis was sponsored by MINGLE to participate in the following conferences
and workshops:
- IX IMA Conference on the Mathematics of surfaces,
September 3-6, 2000,
Cambridge, UK
- MINGLE workshop,
January 18-19, 2001,
Grenoble, France,
giving a talk about "Geometric Analysis of Recursive Subdivision"
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