<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><DIV>Check out:</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Fast exact and approximate geodesics on meshes.</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">V. Surazhsky, T. Surazhsky, D. Kirsanov, S. Gortler, H. Hoppe.</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">ACM SIGGRAPH 2005, 553-560.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR class="khtml-block-placeholder"></DIV><BR><DIV><DIV>On Feb 6, 2007, at 4:00 PM, Karthik Krishnan wrote:</DIV><BR class="Apple-interchange-newline"><BLOCKQUOTE type="cite">Hi,<BR><BR>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 :<BR> <A href="http://public.kitware.com/pipermail/vtkusers/2005-June/080306.html"> http://public.kitware.com/pipermail/vtkusers/2005-June/080306.html</A><BR><BR>I played around with Rasmus Paulsen's code that computes the Dijkstra's shortest path between two vertices (Graph geodesics). [<A href="http://www2.imm.dtu.dk/~rrp/VTK/"> http://www2.imm.dtu.dk/~rrp/VTK/</A>], hoping to get the shortest path using Dijkistra and then try to smooth the resulting zig-zagged curve.<BR><BR>It sort of works if the mesh is very dense. Often, it gives non-intuitive results.<BR><BR>Attached is an example:<BR><BR>- The input polydata is <A href="http://public.kitware.com/pub/itk/UsersITK/vtkDijkstra/ellipsoid.png">http://public.kitware.com/pub/itk/UsersITK/vtkDijkstra/ellipsoid.png </A><BR>- The result is : <A href="http://public.kitware.com/pub/itk/UsersITK/vtkDijkstra/DijkstraGeodesic1.png">http://public.kitware.com/pub/itk/UsersITK/vtkDijkstra/DijkstraGeodesic1.png</A><BR><BR>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. <BR><BR>Any thoughts. Anybody else using geodesics for similar purposes ?<BR><BR>Thanks<BR><BR><SPAN class="sg">-- <BR>Karthik Krishnan<BR>R&D Engineer,<BR>Kitware Inc. </SPAN><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">_______________________________________________</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">vtk-developers mailing list</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><A href="mailto:vtk-developers@vtk.org">vtk-developers@vtk.org</A></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><A href="http://www.vtk.org/mailman/listinfo/vtk-developers">http://www.vtk.org/mailman/listinfo/vtk-developers</A></DIV> </BLOCKQUOTE></DIV><BR></BODY></HTML>