Hi Ufuk, vtkSurfaceReconstructionFilter with programmable filter detects holes in your data although they are somewhat inaccurate. As Ken mentioned, it would fail for other shapes with holes. But I think it is a little funny approach. ---- import vtk
pdi = self.GetInput() pdo = self.GetOutput() surf = vtk.vtkSurfaceReconstructionFilter() surf.SetInputData(pdi) surf.SetSampleSpacing(0.02) cf = vtk.vtkContourFilter() cf.SetInputConnection(surf.GetOutputPort()) cf.SetValue(0, 0.0) reverse = vtk.vtkReverseSense() reverse.SetInputConnection(cf.GetOutputPort()) reverse.ReverseCellsOn() reverse.ReverseNormalsOn() reverse.Update() pdo.ShallowCopy(reverse.GetOutput()) ---- Thanks 2017-11-15 0:04 GMT+09:00 Moreland, Kenneth <kmo...@sandia.gov>: > Ufuk, > > The short answer is, no. You cannot keep the Delaunay2D filter from filling > holes. > > The mathematical description of Delaunay triangulation fills in all the space > in the convex hull of the points. The question about having the Delaunay > triangulation keeping open space that is supposed to be empty comes up > frequently on this list. However, generally identifying what should not be > filled is not easy to describe, especially in a general sense. When you ask > me about the “hole” in your data, I, as a human, can immediately identify > what you mean. But can you describe it in such a way that it can be easily > picked out by a computer? I cannot. And even if we did come up with > something, there is a good chance it would fail for holes of other shapes. > > That said, you might be able to resolve the problem by removing the triangles > over the hole after you create the surface. I note that what you mean by a > hole is a region where points are spread out, so we could start by removing > big triangles. You can identify triangle size using the Mesh Quality filter. > Add the Mesh Quality filter and change Triangle Quality Measure to Area. > After you run that, use the threshold filter to remove all triangles with a > “quality” (actually area) greater than 0.01. > > That removes some of the triangles in the holes, but not all of them. You > will also see that the remaining triangles are skinny ones that stretch > across cords of the circular hole. So, we could also remove skinny triangles. > Run the Mesh Quality filter again on the output, this time setting the > Triangle Quality Measure to Radius Ratio. Then use the Threshold filter again > to remove triangles greater than a value somewhere in the range of 5 to 15. > You might notice at this point that it is getting difficult to specify values > that work well around the holes along the sides. Low values start removing > valid triangles on the sides. High values leave some of the holes covered. > This is what I meant by it being difficult to describe the holes to a > computer. > > An alternate approach is to select the triangles over the wholes, invert the > selection, and then extract the selection. You could also do that to the > result of the procedure I just gave you. > > One final note. You are using Delaunay 2D on a set of data that is 3D. I > presume you are aware that Delaunay 2D is actually projecting all of your > points onto a plane and finding a triangulation there. It is not finding a > surface in 3D. The only way to find the true 3D surface (in ParaView) would > be to do a Delaunay 3D and then extract the external faces. > > -Ken > > > On 11/14/17, 5:11 AM, "ParaView on behalf of Ufuk Utku Turuncoglu (BE)" > <paraview-boun...@paraview.org on behalf of u.utku.turunco...@be.itu.edu.tr> > wrote: > > Hi, > > I am trying to create surface for a poly data (see attached figure). In > this case, if i use Delaunay2D filter, it creates surface but it also > fills the holes. So, i just wonder that is it possible to create surface > for it without filling holes. You could also find a simple dataset as > attachment. > > Regards, > > --ufuk > > > > _______________________________________________ > Powered by www.kitware.com > > Visit other Kitware open-source projects at > http://www.kitware.com/opensource/opensource.html > > Please keep messages on-topic and check the ParaView Wiki at: > http://paraview.org/Wiki/ParaView > > Search the list archives at: http://markmail.org/search/?q=ParaView > > Follow this link to subscribe/unsubscribe: > http://public.kitware.com/mailman/listinfo/paraview _______________________________________________ Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the ParaView Wiki at: http://paraview.org/Wiki/ParaView Search the list archives at: http://markmail.org/search/?q=ParaView Follow this link to subscribe/unsubscribe: http://public.kitware.com/mailman/listinfo/paraview
