Erich Hartmann

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Surface triangulations are necessary in applying finite element methods for solving mechanical problems and for displaying surfaces by ray tracing or other hidden line algorithms. A parametric surface can be a triangulated by triangulating its (plane) area of definition. However, the images of these triangles in object space may vary unacceptably for the(More)
The normalform h= 0 of a curve (surface) is a generalization of the Hesse normalform of a line in R2 (plane in R3). It was introduced and applied to curve and surface design in recent papers. For determining the curvature of a curve (surface) defined via normalforms it is necessary to have formulas for the second derivatives of the normalform function h(More)
We introduce a method for curvature-continuous (G 2) interpolation of an arbitrary sequence of points on a surface (implicit or parametric) with prescribed tangent and geodesic curvature at every point. The method can also be used forG 2 blending of curves on surfaces. The interpolation/blending curve is the intersection curve of the given surface with a(More)
Ophthalmologists today need to be able to determine visual acuity accurately more and more frequently. The result depends not only on the optotypes but also on the investigation methods used. Possible errors are discussed.
A method for parameterizing nearly arbitrary implicit plane/space curves and surfaces is introduced. The parameterizations are of class Cn−1 if the given curves/surfaces are of class Cn. The computation of points and derivatives is performed numerically. These parameterizations can be used for controlled determination of points on curves and surfaces and(More)
T. ap Rees, Cambridge Th. Boller, Basel J. Carman, Logan F. Constabel, Saskatoon • L. Erdei, Szeged • E. F. Elstner, München W. H. 0. Ernst, Amsterdam • C. V. Glvan, Durham, NH P. M. Gresshoff, Knoxville • W. Haupt, Erlangen D. Heß, Stuttgart-Hohenheim • H. Kende, East Lansing • E. Komor, Bayreuth H. K. Lichtenthaler, Karlsruhe • H. Lörz, Hamburg • U.(More)