[vtkusers] Mark specific points on a poldata object

[Wenlong Wang]

Hi, David,

Thank you for your help.

I made it in your way. Thank you so much.

Have a good night.

Wenlong

2011/10/11 David E DeMarle <dave.demarle at kitware.com>

> In my quick scan of your code I didn't notice that you are already
> taking approach #2. Sorry about that.
>
> VTK won't draw points without cells. Add one VTK_VERTEX cell for every
> landmark point and I think you will see the result. One way to do that
> is feed newpolydata into the glyph filter.
>
> David E DeMarle
> Kitware, Inc.
> R&D Engineer
> 21 Corporate Drive
> Clifton Park, NY 12065-8662
> Phone: 518-881-4909
>
>
>
> 2011/10/11 Wenlong Wang <scc.wwl at gmail.com>:
> > Hi, David,
> >
> > Thank you for your reply.
> >
> > Yes, the code clip I attached is building a polydata object for the
> > landmarks only and there is another polydata object for the surface.
> >
> > What I want to make is the landmarks are drawn on the screen while
> another
> > surface is show. However, when the application runs, only the surface is
> > shown, the landmarks are never appreared. I tried to change the
> z-coordinate
> > by hand, but they still don't appear.
> >
> > Could it be anything wrong with the visualization pipeline? I think I've
> > accomplish the basic operation to visualize actors in the code clip.
> >
> > Thank you for your kind help。
> >
> > Wenlong
> >
> > 2011/10/11 David E DeMarle <dave.demarle at kitware.com>
> >>
> >> You have to have as many tuples in the scalars array as there are
> >> points in the polydata. You have only as many tuples as there are
> >> landmark points.
> >>
> >> Alternatively might make another polydata that contains only the
> >> landmark points and draw both polydata. Scale the landmark polydata up
> >> slightly to avoid z-tearing.
> >>
> >> David E DeMarle
> >> Kitware, Inc.
> >> R&D Engineer
> >> 21 Corporate Drive
> >> Clifton Park, NY 12065-8662
> >> Phone: 518-881-4909
> >>
> >>
> >>
> >> On Tue, Oct 11, 2011 at 9:17 AM, Wenlong Wang <scc.wwl at gmail.com>
> wrote:
> >> > Dear all,
> >> >
> >> > Is there anyone know how to change the color of points with specific
> >> > point
> >> > ID?
> >> >
> >> > I do it like this, but the surface appeared but none of these point is
> >> > shown.
> >> >
> >> > Here is the code,
> >> >
> >> >     vtkPoints* newpoints = vtkPoints::New();
> >> >     for (int i = 0; i < sizeof(landmarks)/sizeof(double); i++)
> >> >     {
> >> >         double temp_point[3];
> >> >         points->GetPoint(vtkIdType(landmarks[i]), temp_point);
> >> >         newpoints->InsertPoint(vtkIdType(i), temp_point[0],
> >> > temp_point[1],
> >> > temp_point[2]);
> >> >     }
> >> >
> >> >     vtkPolyData* newpolydata = vtkPolyData::New();
> >> >     newpolydata->SetPoints(newpoints);
> >> >
> >> >     vtkFloatArray* newarray = vtkFloatArray::New();
> >> >     for (int i = 0; i < sizeof(landmarks)/sizeof(double); i++)
> >> >     {
> >> >         newarray->InsertTuple1(vtkIdType(i), double(i));
> >> >     }
> >> >
> >> >     newpolydata->GetPointData()->SetScalars(newarray);
> >> >
> >> >     vtkPolyDataMapper* newmapper = vtkPolyDataMapper::New();
> >> >     newmapper->SetInput(newpolydata);
> >> >     newmapper->SetScalarRange(0, 7);
> >> >     newmapper->SetScalarVisibility(0);
> >> >
> >> >     vtkActor* newactor = vtkActor::New();
> >> >     newactor->SetMapper(newmapper);
> >> >     newactor->GetProperty()->SetColor(0.0, 1.0, 0.0);
> >> >     newactor->GetProperty()->SetPointSize(3);
> >> >
> >> >     ren->AddActor(newactor);
> >> >     renWin->AddRenderer(ren);
> >> >
> >> >     ren->Render();
> >> >     renWin->Render();
> >> >
> >> > where 'ren' is a vtkRenderer object, 'renWin' is a vtkRenderWindow
> >> > object,
> >> > and 'landmarks' is an array stores vtk point IDs.
> >> >
> >> > Can anybody help me with this? I'll be very grateful.
> >> >
> >> > Thank you all so much.
> >> >
> >> > Bests
> >> > Wenlong
> >> >
> >> > _______________________________________________
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>
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