[vtkusers] Uneven colors after the vtkButterflySubdivisionFilter

[Bill Lorensen]

I was able to duplicate your problem. I believe the problem is trying to
approximate the unsigned char 3-component colors. Butterfly is an
approximating subdivision scheme, while loop is an interpolating scheme. I
think if you assigned scalar float, single component values and mapper them
through a lookup table you would get good results. But I'm not sure that
would accomplish what you want.



On Sat, Apr 20, 2013 at 2:23 PM, Bill Lorensen <bill.lorensen at gmail.com>wrote:

> This better. Just to be sure, I assume this code also produces bad results?
>
>
>
> On Sat, Apr 20, 2013 at 1:39 PM, DivyaS <div.anand141 at gmail.com> wrote:
>
>> Sure, please check this code - I have removed all the unnecessary code. I
>> have added comments for each of the steps.
>>
>>             //Defining a cylinder source.
>>             vtkCylinderSource cylinderSource = vtkCylinderSource.New();
>>             cylinderSource.Update();
>>
>>             vtkTriangleFilter triangles = vtkTriangleFilter.New();
>>             triangles.SetInput(cylinderSource.GetOutput());
>>             triangles.Update();
>>             vtkPolyData originalMesh;
>>             originalMesh = triangles.GetOutput();
>>
>>             vtkUnsignedCharArray colors = vtkUnsignedCharArray.New();
>>             colors.SetNumberOfComponents(3);
>>             colors.SetNumberOfTuples(originalMesh.GetNumberOfPolys());
>>             colors.SetName("Colors");
>>
>>             //Creating an array to store the values according to which the
>> colors are selected.
>>             //Values are inserted for each of the points in the polydata
>>             int[] colorAT = new int[originalMesh.GetNumberOfPolys()];
>>             for (int i = 0; i < originalMesh.GetNumberOfPolys(); i++)
>>             {
>>                 colorAT[i] = i;
>>             }
>>
>>             int activationTime;
>>             //Loop to select colors for each of the points in the
>> polydata.
>>             for (int i = 0; i < originalMesh.GetNumberOfPolys(); i++)
>>             {
>>                 activationTime = colorAT[i];
>>                 if (activationTime > 0 && activationTime < 5)
>>                 {
>>                     //Black
>>                     colors.InsertTuple3(i, 255, 255, 0);
>>                 }
>>                 else if (activationTime > 4 && activationTime < 10)
>>                 {
>>                     //Blue
>>                     colors.InsertTuple3(i, 0, 0, 255);
>>                 }
>>                 else if (activationTime > 9 && activationTime < 300)
>>                 {
>>                     //Red
>>                     colors.InsertTuple3(i, 255, 0, 0);
>>                 }
>>             }
>>             originalMesh.GetPointData().SetScalars(colors);
>>
>>             //Subdivision.
>>             int numberOfSubdivisions = 4;
>>             vtkPolyDataAlgorithm subdivisionFilter =
>> vtkButterflySubdivisionFilter.New();
>>
>>
>> ((vtkButterflySubdivisionFilter)subdivisionFilter).SetNumberOfSubdivisions(numberOfSubdivisions);
>>             subdivisionFilter.SetInput(originalMesh);
>>             subdivisionFilter.Update();
>>
>>             vtkRenderWindow renderWindow =
>> renderWindowControl1.RenderWindow;
>>             vtkRenderer renderer = vtkRenderer.New();
>>
>>             //Create a mapper and actor
>>             vtkPolyDataMapper mapper = vtkPolyDataMapper.New();
>>             mapper.SetInputConnection(subdivisionFilter.GetOutputPort());
>>             vtkActor actor = vtkActor.New();
>>             actor.SetMapper(mapper);
>>
>>             renderer.AddActor(actor);
>>             renderer.SetBackground(0, 0, 0);
>>             renderer.ResetCamera();
>>             renderWindow.AddRenderer(renderer);
>>             renderWindow.Render();
>>
>>
>>
>> --
>> View this message in context:
>> http://vtk.1045678.n5.nabble.com/Uneven-colors-after-the-vtkButterflySubdivisionFilter-tp5720205p5720234.html
>> Sent from the VTK - Users mailing list archive at Nabble.com.
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>
>
>
> --
> Unpaid intern in BillsBasement at noware dot com
>



-- 
Unpaid intern in BillsBasement at noware dot com
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