National Repository of Grey Literature 2 records found  Search took 0.01 seconds. 
Envelopes of implicit surfaces
Vráblíková, Jana ; Šír, Zbyněk (advisor) ; Lávička, Miroslav (referee)
The aim of the thesis is to study envelopes and characteristic curves of one parameter systems of quadratic surfaces in real three dimensional space. We define one parameter systems and their envelopes generally and present algebraic geometry approach for en- velope computation using Gröbner bases and elimination theory. We convey a proof of rationality of envelopes of rational one parameter systems of spheres, cones and cylin- ders of revolution using dual space and different models of Laguerre geometry. Then we present a new approach to one parameter systems and their envelopes. We introduce the systems as curves in homogeneous spaces which allows us to study all characteristic curves at a single surface. This approach allows us to prove rationality and even provide an explicit parameterization of characteristic curves and the envelope of a one parameter system of isometric cones of revolution. We provide several other examples illustrating the concepts and results. 1
Discrete connection on triangular meshes
Vráblíková, Jana ; Šír, Zbyněk (advisor) ; Souček, Vladimír (referee)
Abstract. In this thesis we are going to deal with constructing parallel tangent vector fields on discrete surfaces. Ať first, we are going to present theory of tangent vector fields on smooth surfaces in R3 , define notion of connection, which will help us describe tangent vector fields, and we will formulate corollary of Poincare-Hopf theorem, that will tell us that on most surfaces smooth tangent vector field which is nonzero at every point does not exist. Then we are going to introduce analogies of notions from differential geometry for discrete surfaces, which we represent by triangular meshes, and we are going to explain how to use these concepts when constructing tangent vector fields that are parallel at the whole surface. At the end we are going to describe algorithm for constructing these vector fields, which can be found in the electronic attachement, implemented using software Wolfram Mathematica, and we will show its results on several examples.

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1 Vráblíková, Jaroslava
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