[vtkusers] vtkTubeFilter with independently varying radius and color

[Bill Lorensen]

Marcus,

I added the your example here:
http://www.vtk.org/Wiki/VTK/Examples/VisualizationAlgorithms/Cxx/TubesWithVaryingRadiusAndColors

I'll also be adding it the Examples distributed with the vtk source
distribution. I made some minor edits to conform to VTK style.

Thanks for taking the time to do this,

Bill

On Sat, Jan 2, 2010 at 8:47 AM, Bill Lorensen <bill.lorensen at gmail.com> wrote:
> Marcus,
>
> Thanks, I'll add it to the wiki examples and send a pointer.
>
> Bill
>
> On Sat, Jan 2, 2010 at 4:44 AM, Marcus Thamson <markie_thomson at yahoo.de> wrote:
>> Dear All,
>>
>> I have finally solved my little problem, by using SetScalarModeToUsePointFieldData in conjunction with SelectColorArray (in the end nothing special, but I had to find the correct combination of commands...).
>>
>> I came across about 5 other unresolved threads on this same issue, so I have pasted a demonstrative code below in case this helps anyone in the future.
>>
>> Regards, MT
>>
>> // VTK: Spiral with vtkTubeFilter
>> // Varying tube radius and independent RGB colors with an unsignedCharArray
>>
>> #include <math.h>
>> #include <iostream>
>> using namespace std;
>>
>> #include <vtkPolyData.h>
>> #include <vtkPoints.h>
>> #include <vtkCellArray.h>
>> #include <vtkDoubleArray.h>
>> #include <vtkPolyData.h>
>> #include <vtkPointData.h>
>>
>> #include <vtkCell.h>
>> #include <vtkCellData.h>
>> #include <vtkDataSet.h>
>> #include <vtkDataSetAttributes.h>
>> #include <vtkProperty.h>
>> #include <vtkSmartPointer.h>
>> #include <vtkTubeFilter.h>
>>
>> #include <vtkDataSetMapper.h>
>> #include <vtkPolyDataMapper.h>
>> #include <vtkActor.h>
>> #include <vtkRenderer.h>
>> #include <vtkRenderWindow.h>
>> #include <vtkRenderWindowInteractor.h>
>> #include <vtkInteractorStyleTrackballCamera.h>
>>
>> #define PI 3.14159265
>>
>> int main()
>> {
>>        // Spiral tube
>>        double vx, vy, vz;
>>        unsigned int nV=256;            // No. of vertices
>>        unsigned int ncyc=5;    // No. of spiral cycles
>>        double Rt1=0.1, Rt2=0.5;                                // Start/end tube radii
>>        double Rs=2;                            // Spiral radius
>>        double h=10;                            // Height
>>        unsigned int Ntv=8;             // No. of surface elements for each tube vertex
>>
>>        unsigned int i;
>>
>>        vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();
>>        for(i=0; i<nV; i++) {
>>                // Spiral coordinates
>>                vx = Rs*cos(2*PI*ncyc*i/(nV-1));
>>                vy = Rs*sin(2*PI*ncyc*i/(nV-1));
>>                vz = h*i/nV;
>>                points->InsertPoint(i,vx,vy,vz);
>>        }
>>
>>        vtkSmartPointer<vtkCellArray> lines = vtkSmartPointer<vtkCellArray>::New();
>>        lines->InsertNextCell(nV);
>>        for (i=0; i<nV; i++) lines->InsertCellPoint(i);
>>
>>        vtkSmartPointer<vtkPolyData> polyData = vtkSmartPointer<vtkPolyData>::New();
>>        polyData->SetPoints(points);
>>        polyData->SetLines(lines);
>>        polyData->BuildLinks();
>>
>>        // Varying tube radius - vary using sine-function
>>        vtkSmartPointer<vtkDoubleArray> tuberad = vtkSmartPointer<vtkDoubleArray>::New();
>>        tuberad->SetName("tuberad");
>>        tuberad->SetNumberOfTuples(nV);
>>        for (i=0 ;i<nV ; i++) tuberad->SetTuple1(i,Rt1+(Rt2-Rt1)*sin(PI*i/(nV-1)));
>>        polyData->GetPointData()->AddArray(tuberad);
>>        polyData->GetPointData()->SetActiveScalars("tuberad");
>>
>>        // RBG array (could add A channel too I guess...)
>>        // Varying from blue to red
>>        vtkSmartPointer<vtkUnsignedCharArray> cols = vtkSmartPointer<vtkUnsignedCharArray>::New();
>>        cols->SetName("cols");
>>        cols->SetNumberOfComponents(3);
>>        cols->SetNumberOfTuples(nV);
>>        for (i=0; i<nV ; i++) {
>>                cols->InsertTuple3(i, int(255*i/(nV-1)) , 0 , int(255*(nV-1-i)/(nV-1)) );
>>        }
>>        polyData->GetPointData()->AddArray(cols);
>>
>>        vtkSmartPointer<vtkTubeFilter> tube = vtkSmartPointer<vtkTubeFilter>::New();
>>        tube->SetNumberOfSides(Ntv);
>>        tube->SetInput(polyData);
>>        tube->SetVaryRadiusToVaryRadiusByAbsoluteScalar();
>>
>>        vtkSmartPointer<vtkPolyDataMapper> mapper = vtkSmartPointer<vtkPolyDataMapper>::New();
>>        mapper->SetInput(tube->GetOutput());
>>        mapper->ScalarVisibilityOn();
>>        mapper->SetScalarModeToUsePointFieldData();
>>        mapper->SelectColorArray("cols");
>>
>>        vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();
>>        actor->SetMapper(mapper);
>>
>>        vtkRenderer *renderer = vtkRenderer::New();
>>        renderer->AddActor(actor);
>>
>>        vtkRenderWindow *renWin = vtkRenderWindow::New();
>>        vtkRenderWindowInteractor *iren = vtkRenderWindowInteractor::New();
>>
>>        iren->SetRenderWindow(renWin);
>>        renWin->AddRenderer(renderer);
>>        renWin->SetSize(500,500);
>>        renWin->Render();
>>
>>        vtkInteractorStyleTrackballCamera *style =
>>                vtkInteractorStyleTrackballCamera::New();
>>        iren->SetInteractorStyle(style);
>>
>>        iren->Start();
>>
>>        renderer->Delete();
>>        renWin->Delete();
>>        iren->Delete();
>>        style->Delete();
>>
>>        return 0;
>> }
>>
>>
>>
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