English

The extended oloid and its inscribed quadrics

Metric Geometry 2016-03-02 v3 Algebraic Geometry

Abstract

The oloid is the convex hull of two circles with equal radius in perpendicular planes so that the center of each circle lies on the other circle. It is part of a developable surface which we call extended oloid. We determine the tangential system of all inscribed quadrics Qλ\mathcal{Q}_\lambda of the extended oloid O\mathcal{O} where λ\lambda is the system parameter. From this result we conclude parameter equations of the touching curve Cλ\mathcal{C}_\lambda between O\mathcal{O} and Qλ\mathcal{Q}_\lambda, the edge of regression R\mathcal{R} of O\mathcal{O}, and the asymptotes of R\mathcal{R}. Properties of the touching curves Cλ\mathcal{C}_\lambda are investigated, including the case that λ±\lambda\rightarrow\pm\infty. The self-polar tetrahedron of the tangential system Qλ\mathcal{Q}_\lambda is obtained. The common generating lines of O\mathcal{O} and any ruled surface Qλ\mathcal{Q}_\lambda are determined. Furthermore, we derive the curves which are the images of Cλ\mathcal{C}_\lambda and R\mathcal{R} when O\mathcal{O} is developed onto the plane.

Keywords

Cite

@article{arxiv.1503.07399,
  title  = {The extended oloid and its inscribed quadrics},
  author = {Uwe Bäsel and Hans Dirnböck},
  journal= {arXiv preprint arXiv:1503.07399},
  year   = {2016}
}

Comments

28 pages, 13 figures

R2 v1 2026-06-22T09:01:55.541Z