CGAL users discussion list

[Stefan Salewski <>]

I have a set of circles in 2d, they differ much in size and may partly
or fully overlap. I need to identify the ones which touch the convex
hull of the set, so that I can drop the inner ones.

I have experimented with some sort of graham scan, after circular
sorting and calculation tangents. While that seemed to work for most
cases, I noted that it still may fail for special cases, i.e when there
is a very big difference in size.

Yesterday I found this paper

On Computing the Convex Hull of (Piecewise) Curved Objects by Franz
Aurenhammer and Bert JÜttler
www.igi.tugraz.at/auren/psfiles/aj-cchpco-12.pdf

For me that is a very abstract theoretical description.
Is there a chance to convert that paper into real code?
Or any other suggestions?

Best regards,

Stefan Salewski