[vtkusers] FInding the distance around a surface

[Karthik Krishnan]

You are looking to compute the geodesics on meshes given two points on
its surface. It is non-trivial. Check out :

V. Surazhsky, T. Surazhsky, D. Kirsanov, S. Gortler, H. Hoppe. "Fast
Exact and Approximate Geodesics on Meshes", SIGGRAPH 2005.

I added a class that computes the discretized version of the same on
polygonal surfaces is in vtkDijkstraGraphGeodesicPath.cxx . This
computes the geodesic path between two points, with geodesic lying
along the edges of the mesh.

Hoppe's paper describes a  "continuous" version of Dijkstra, so that
the geodesics are not contrained to the edges of the mesh.

Should you decide to add such a class to vtk, vtkGeodesicPath would be
a could place to subclass.

HTH
--
karthik


On Tue, Aug 5, 2008 at 8:57 AM, Robert Caldwell
<allan.caldwell at mail.mcgill.ca> wrote:
> Hi,
> I am working with a program that displays surfaces meshs of vtkPolyData polygons. I am trying to mesure across the surface between two picked points. So need to somehow trace line across the surface between the points and get it's length. Can anyone suggest a class for me to use? I was thinking about using a plane including the two points and w/a normal parrellel to the surface, but vtkPlane didn't seem to be able to return an intersection with a surface.
>
> -thanks,Robert A. Caldwell
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-- 
Karthik Krishnan
R&D Engineer,
Kitware Inc.
Ph: 518 371 3971 x119
Fax: 518 371 3971