[vtk-developers] Geodesics on polygonal surfaces

[Rasmus Reinhold Paulsen]

Hi Karthik,

 

I have not done any work on the Geodesics routines since June 2005, so
unfortunately I do not have any hidden golden nuggets :)

 

Cheers,
Rasmus

 

PS. As can be seen I am gradually changing my academic email address
into my new one rrp at oticon.dk

 

________________________________

From: vtk-developers-bounces+rrp=oticon.dk at vtk.org
[mailto:vtk-developers-bounces+rrp=oticon.dk at vtk.org] On Behalf Of
Karthik Krishnan
Sent: 7. februar 2007 00:01
To: vtk-developers at vtk.org
Cc: rrp at imm.dtu.dk
Subject: [vtk-developers] Geodesics on polygonal surfaces

 

Hi,

I'm writing a widget that can draw on polygonal datasets. So an need an
algorithm that can trace geodesics on surfaces. I dug up an old thread :
  http://public.kitware.com/pipermail/vtkusers/2005-June/080306.html

I played around with Rasmus Paulsen's code that computes the Dijkstra's
shortest path between two vertices (Graph geodesics). [
http://www2.imm.dtu.dk/~rrp/VTK/ <http://www2.imm.dtu.dk/~rrp/VTK/> ],
hoping to get the shortest path using Dijkistra and then try to smooth
the resulting zig-zagged curve.

It sort of works if the mesh is very dense. Often, it gives
non-intuitive results.

Attached is an example:

- The input polydata is
http://public.kitware.com/pub/itk/UsersITK/vtkDijkstra/ellipsoid.png 
- The result is :
http://public.kitware.com/pub/itk/UsersITK/vtkDijkstra/DijkstraGeodesic1
.png

The curve ends up hugging the latitudes of the ellipsoid for a while to
get to its final destination, instead of zigzagging its way through the
latitudes and longitudes. 

Any thoughts. Anybody else using geodesics for similar purposes ?

Thanks

-- 
Karthik Krishnan
R&D Engineer,
Kitware Inc. 

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