Abstract
We discuss three geometric constructions and their relations, namely the offset, the conchoid and the pedal construction. The offset surface F d of a given surface F is the set of points at fixed normal distance d of F. The conchoid surface G d of a given surface G is obtained by increasing the radius function by d with respect to a given reference point O. There is a nice relation between offsets and conchoids: The pedal surfaces of a family of offset surfaces are a family of conchoid surfaces. Since this relation is birational, a family of rational offset surfaces corresponds to a family of rational conchoid surfaces and vice versa. We present theoretical principles of this mapping and apply it to ruled surfaces and quadrics. Since these surfaces have rational offsets and conchoids, their pedal and inverse pedal surfaces are new classes of rational conchoid surfaces and rational offset surfaces.
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Albano, A., Roggero, M.: Conchoidal transform of two plane curves. Appl. Algebra Eng. Commun. Comput. 21, 309–328 (2010)
Arrondo, E., Sendra, J., Sendra, J.R.: Parametric generalized offsets to hypersurfaces. J. Symb. Comput. 23, 267–285 (1997)
Dietz, R., Hoschek, J., Jüttler, B.: An algebraic approach to curves and surfaces on the sphere and other quadrics. Comput. Aided Geom. Design 10, 211–229 (1993)
Farouki, R.T.: Pythagorean–Hodograph curves. In: Farin, G., Hoschek, J., Kim, M.-S. (eds.) Handbook of Computer Aided Geometric Design. Elsevier, Amsterdam (2002)
Farouki, R.T.: Pythagorean–Hodograph Curves: Algebra and Geometry Inseparable. Springer, Berlin (2008)
Gruber, D., Peternell, M.: Conchoid surfaces of quadrics. J. Symb. Comput. 59, 36–53 (2013)
Hilton, H.: Plane Algebraic Curves. Clarendon Press, Oxford (1920)
Kerrick, A.H.: The limacon of Pascal as a basis for computed and graphic methods of determining astronomic positions. J. Inst. Navig. 6, 310–316 (1959)
Krasauskas, R., Peternell, M.: Rational offset surfaces and their modeling applications. In: Emiris, I.Z., Sottile, F., Theobald, Th. (eds.) IMA Volume 151: Nonlinear Computational Geometry, pp. 109–136 (2010)
Lin, W., Yu, Z., Yuang, E., Luk, K.: Conchoid of nicomedes and limacon of pascal as electrode of static field and a waveguide of high frecuency wave. PIER 30, 273–284 (2001)
Loria, G.: Spezielle Algebraische und Transzendente Ebene Kurven: Theorie und Geschichte. Teubner, Leipzig (1911)
Peternell, M., Pottmann, H.: A Laguerre geometric approach to rational offsets. Comput. Aided Geom. Des. 15, 223–249 (1998)
Peternell, M., Gruber, D., Sendra, J.: Conchoid surfaces of rational ruled surfaces. Comput. Aided Geom. Des. 28, 427–435 (2011)
Pottmann, H.: Rational curves and surfaces with rational offsets. Comput. Aided Geom. Des. 12, 175–192 (1995)
Pottmann, H., Shi, L., Skopenkov, M.: Darboux cyclides and webs from circles. Comput. Aided Geom. Des. 29, 77–97 (2012)
Schicho, J.: Proper parametrization of real tubular surfaces. J. Symb. Comput. 30, 583–593 (2000)
Sendra, J.R., Sendra, J.: Algebraic analysis of offsets to hypersurfaces. Math. Z. 234, 697–719 (1999)
Sendra, J.R., Sendra, J.: An algebraic analysis of conchoids to algebraic curves. Appl. Algebra Eng. Commun. Comput. 19, 285–308 (2008)
Sendra, J., Sendra, J.R.: Rational parametrization of conchoids to algebraic curves. Appl. Algebra Eng. Commun. Comput. 21, 413–428 (2010)
Sendra, J.R., Winkler, F., Pérez-Diaz, S.: Rational Algebraic Curves: A Computer Algebra Approach. In: Series Algorithms and Computation in Mathematics, Vol. 22. Springer, Heidelberg (2007)
Szmulowicz, F.: Conchoid of Nicomedes from reflections and refractions in a cone. Am. J. Phys. 64, 467–471 (1996)
Vršek, J., Lávicka, M.: Exploring hypersurfaces with offset-like convolutions. Comput. Aided Geom. Des. 29, 676–690 (2012)
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Peternell, M., Gotthart, L., Sendra, J. et al. Offsets, conchoids and pedal surfaces. J. Geom. 106, 321–339 (2015). https://doi.org/10.1007/s00022-014-0251-1
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DOI: https://doi.org/10.1007/s00022-014-0251-1