[vtkusers] Isosurface Extraction

[Bill Lorensen]

There are no topological "errors" in the vtk implementation of Marching Cubes.

Bill

On Mon, Apr 14, 2008 at 10:46 AM, Marcel Weiss <mweiss at cbs.mpg.de> wrote:
> there is only one scalar array (created from a level set result with spherical topology of the zero level set)
>
> the problem is the used algorithm. standard MC (as it is implemented in the used countour filter) is known to created topology "errors" in some regions.
>
> I am looking for on of the existing alternatives/extensions already implemented in VTK/ITK.
>
> m.weiss
>
>
> ----- Original Message -----
> From: "Amy Squillacote" <ahs at cfdrc.com>
> To: "r jamieson" <r.jamieson at reading.ac.uk>
> Cc: "vtkMailingList" <vtkusers at vtk.org>
> Sent: Monday, April 14, 2008 3:24:06 PM (GMT+0100) Europe/Berlin
> Subject: Re: [vtkusers] Isosurface Extraction
>
> Does your data set have more than one point scalar array? Is it possible
> that the contour filter is actually operating on an array with a
> different scalar range?
>
> - Amy
>
> r.jamieson at reading.ac.uk wrote:
> > HI Bill,
> >
> > My values range from 1 to 562043.31.
> >
> > Ronan
> >
> >
> > On Apr 13 2008, Bill Lorensen wrote:
> >
> >> What is the scalar range of your input?
> >>
> >> Bill
> >>
> >> On Sun, Apr 13, 2008 at 9:34 AM, ronan <r.jamieson at reading.ac.uk> wrote:
> >>> Hi,
> >>>
> >>> I am trying to get my head around isosurfaces extraction and i have
> >>> tried to write a c++ program to do a simple extraction, but i cannot
> >>> see any isosurfaces, i have got a wireframe box around the
> >>> space...but no isosurface, i have attached my code
> >>>
> >>> I would be greatful if some one could point out where i have gone
> >>> wrong.
> >>>
> >>> Thanks in advance
> >>>
> >>> Ronan
> >>>
> >>> int main()
> >>> {
> >>>
> >>> char *c1;
> >>> // Setup standard rendering
> >>>
> >>> vtkRenderer *ren1 = vtkRenderer::New();
> >>>   ren1->SetBackground(0.8,0.8,0.8);
> >>>
> >>> vtkRenderWindow *renWin = vtkRenderWindow::New();
> >>>   renWin->AddRenderer(ren1);
> >>>   renWin->SetSize(400,300);
> >>>
> >>> vtkRenderWindowInteractor *iren = vtkRenderWindowInteractor::New();
> >>> iren->SetRenderWindow(renWin);
> >>>
> >>> //Read data from office simulation data file
> >>>
> >>> vtkDataSetReader *dataSource = vtkDataSetReader::New();
> >>>   dataSource->SetFileName("/home/ronan/Develop/Data/office.vtk");
> >>>   dataSource->DebugOn();
> >>>   dataSource->SetScalarsName(c1);
> >>>   dataSource->Update();
> >>>
> >>> // Create and initialize a dataset outline
> >>> // The outline of the data puts the data in context.
> >>>
> >>> vtkOutlineFilter *outline = vtkOutlineFilter::New();
> >>>   outline->SetInputConnection(dataSource->GetOutputPort());
> >>>
> >>> vtkPolyDataMapper *outlineMapper = vtkPolyDataMapper::New();
> >>>   outlineMapper->SetInputConnection(outline->GetOutputPort());
> >>>
> >>> vtkActor *outlineActor = vtkActor::New();
> >>>   outlineActor->SetMapper(outlineMapper);
> >>>   outlineActor->GetProperty()->SetColor(0, 0, 0);
> >>>
> >>> ren1->AddActor(outlineActor);
> >>>
> >>> //Create an iso-surface using Marching Cubes
> >>> vtkContourFilter *iso = vtkContourFilter::New();
> >>>   iso->SetInputConnection(dataSource->GetOutputPort());
> >>>   iso->ComputeScalarsOn();
> >>>   iso->SetValue(0, 14);
> >>>   iso->Update();
> >>>
> >>> //vtkDataSetMapper *isoMapper = vtkDataSetMapper::New();
> >>> vtkPolyDataMapper *isoMapper = vtkPolyDataMapper::New();
> >>>   isoMapper->SetInputConnection(iso->GetOutputPort());
> >>>   isoMapper->ScalarVisibilityOn();
> >>>   isoMapper->SetScalarModeToUsePointFieldData();
> >>>   isoMapper->SetScalarRange(0, 1200);
> >>>
> >>> vtkActor *isoActor = vtkActor::New();
> >>>   isoActor->SetMapper(isoMapper);
> >>>   isoActor->GetProperty()->SetColor(0.9804, 0.9216, 0.8431);
> >>>
> >>> ren1->AddActor(isoActor);
> >>>
> >>> renWin->Render();
> >>>  iren->Start();
> >>> _______________________________________________
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> >>>
> >>
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> >
> >
>
> --
> Amy Squillacote                    Phone: (256) 726-4839
> Computer Scientist                 Fax: (256) 726-4806
> CFD Research Corporation           Web: http://www.cfdrc.com
> 215 Wynn Drive, Suite 501
> Huntsville, AL  35805
>
>
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