Step-By-Step Straight Skeletons (Media Exposition)

Authors Günther Eder , Martin Held , Peter Palfrader

Thumbnail PDF


  • Filesize: 456 kB
  • 4 pages

Document Identifiers

Author Details

Günther Eder
  • Universität Salzburg, FB Computerwissenschaften, Austria
Martin Held
  • Universität Salzburg, FB Computerwissenschaften, Austria
Peter Palfrader
  • Universität Salzburg, FB Computerwissenschaften, Austria

Cite AsGet BibTex

Günther Eder, Martin Held, and Peter Palfrader. Step-By-Step Straight Skeletons (Media Exposition). In 36th International Symposium on Computational Geometry (SoCG 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 164, pp. 76:1-76:4, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2020)


We present two software packages for computing straight skeletons: Monos, our implementation of an algorithm by Biedl et al. (2015), computes the straight skeleton of a monotone input polygon, and Surfer2 implements a generalization of an algorithm by Aichholzer and Aurenhammer (1998) to handle multiplicatively-weighted planar straight-line graphs as input. The graphical user interfaces that ship with our codes support step-by-step computations, where each event can be investigated and studied by the user. This makes them a canonical candidate for educational purposes and detailed event analyses. Both codes are freely available on GitHub.

Subject Classification

ACM Subject Classification
  • Theory of computation → Computational geometry
  • weighted straight skeleton
  • implementation
  • visualization
  • graphical user interface
  • education


  • Access Statistics
  • Total Accesses (updated on a weekly basis)
    PDF Downloads


  1. Oswin Aichholzer and Franz Aurenhammer. Straight Skeletons for General Polygonal Figures in the Plane. In Voronoi’s Impact on Modern Sciences II, volume 21, pages 7-21. Institute of Mathematics of the National Academy of Sciences of Ukraine, 1998. URL:
  2. Oswin Aichholzer, Franz Aurenhammer, David Alberts, and Bernd Gärtner. A Novel Type of Skeleton for Polygons. Journal of Universal Computer Science, 1(12):752-761, 1995. URL:
  3. Therese Biedl, Martin Held, Stefan Huber, Dominik Kaaser, and Peter Palfrader. A Simple Algorithm for Computing Positively Weighted Straight Skeletons of Monotone Polygons. Information Processing Letters, 115(2):243-247, 2015. URL:
  4. Günther Eder, Martin Held, and Peter Palfrader. On Implementing Straight Skeletons: Challenges and Experiences. In 36th International Symposium on Computational Geometry, SoCG 2020, volume 164 of LIPIcs, pages 38:1-38:16, Zürich, Switzerland, 2020. Google Scholar
  5. David Eppstein and Jeff Erickson. Raising Roofs, Crashing Cycles, and Playing Pool: Applications of a Data Structure for Finding Pairwise Interactions. Discrete & Computational Geometry, 22(4):569-592, 1999. URL:
  6. Martin Held and Peter Palfrader. Straight Skeletons with Additive and Multiplicative Weights and Their Application to the Algorithmic Generation of Roofs and Terrains. Computer-Aided Design, 92(1):33-41, 2017. URL:
  7. Peter Palfrader, Martin Held, and Stefan Huber. On Computing Straight Skeletons by Means of Kinetic Triangulations. In Proceedings of the 20th Annual European Symposium on Algorithms (ESA), pages 766-777, 2012. URL: