如何创建vtk七角棱镜（7个面有4个顶点，2个面有7个顶点）

Question

在vtk中，您可以使用vtkUnstructuredGrid将六角形棱镜单元添加到InsertNextCell (int type, vtkIdType npts, vtkIdType *ptIds)。这很好，但我想在vtkUnstructuredGrid中包含一个七边形和八边形棱镜。单元格类型未在vtk中定义...

只是为了澄清我对c#使用的疑问，但c++或python示例就足以将其翻译为c#。

回到问题，我首先复制并稍微修改了代码in this example以获得体素（8分和celltype = 11）

            vtkPoints points = vtkPoints.New();
            points.InsertNextPoint(-1.0, -1.0, -1.0);
            points.InsertNextPoint(1.0, -1.0, -1.0);
            points.InsertNextPoint(1.0, 1.0, -1.0);
            points.InsertNextPoint(-1.0, 1.0, -1.0);
            points.InsertNextPoint(-1.0, -1.0, 1.0);
            points.InsertNextPoint(1.0, -1.0, 1.0);
            points.InsertNextPoint(1.0, 1.0, 1.0);
            points.InsertNextPoint(-1.0, 1.0, 1.0);
            vtkUnstructuredGrid unstructuredGrid1 = vtkUnstructuredGrid.New();
            unstructuredGrid1.SetPoints(points);
            int[] ptIds = new int[] { 0, 1, 2, 3, 4, 5, 6, 7 };
            IntPtr ptIdsPointer = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(int)) * 8);
            Marshal.Copy(ptIds, 0, ptIdsPointer, 8);
            unstructuredGrid1.InsertNextCell(11, 8, ptIdsPointer);
            Marshal.FreeHGlobal(ptIdsPointer);
            // Create a mapper and actor
            vtkDataSetMapper mapper = vtkDataSetMapper.New();
                  mapper.SetInputConnection(unstructuredGrid1.GetProducerPort());

            vtkActor actor = vtkActor.New();
            actor.SetMapper(mapper);
            actor.GetProperty().SetColor(1, 0, 0);
            actor.GetProperty().SetPointSize(3);
            actor.GetProperty().SetOpacity(1);
            actor.GetProperty().SetLineWidth(2);
            actor.GetProperty().EdgeVisibilityOn();
            Renderer3D.AddActor(actor);

正确显示体素获取：

但是因为我想要一个七面体，我试图使用VTK_POLYHEDRON来调整这个想法，更改告诉pf单元格添加到unstructuredgrid的行

            unstructuredGrid1.InsertNextCell(11, 8, ptIdsPointer);

to（42代表VTK_POLYHEDRON，11代表VTK_VOXEL）和 points = 14

            unstructuredGrid1.InsertNextCell(42, 14, ptIdsPointer);

喜欢this example。我尝试过类似c ++的东西，但我没有得到任何结果

int numberOfVertices = 14;
int numberOfFaces = 9; //how to tell heptagonal prism has 2 faces with 7 vertices and 7 with 4 vertices?
int numberOfFaceVertices = 4;
vtkIdType heptagonPointsIds[14] =  
    {0, 1,  2,  3,  4,  5,  6
     7,  8, 9, 10, 11, 12,13};

//points that only change in z
vtkSmartPointer<vtkPoints> points =  vtkSmartPointer<vtkPoints>::New();
        points->InsertNextPoint(454.6, 678.534, 1.1009301757813); //id 0
        points->InsertNextPoint(454.6, 678.545, 1.1500146484375);//id 1
        points->InsertNextPoint(454.6, 678.556, 1.2255187988281);//id 2
        points->InsertNextPoint(455.1, 678.556, 1.6478076171875);//id 3
        points->InsertNextPoint(455.1, 678.534, 1.7926538085938);//id 4
        points->InsertNextPoint(455.1, 678.545, 1.7166479492188);//id 5
        points->InsertNextPoint(454.85, 678.534, 1.0092297363281);//id 6

        points->InsertNextPoint(454.6, 678.534, 5.1009301757813);//id 7
        points->InsertNextPoint(454.6, 678.545, 5.1500146484375);//id 8
        points->InsertNextPoint(454.6, 678.556, 5.2255187988281);//id 9
        points->InsertNextPoint(455.1, 678.556, 5.6478076171875);//id 10
        points->InsertNextPoint(455.1, 678.534, 5.7926538085938);//id 11
        points->InsertNextPoint(455.1, 678.545, 5.7166479492188);//id 12
        points->InsertNextPoint(454.85, 678.534, 5.0092297363281);//id13    
vtkIdType heptagonPrismFace[9][4] = {
      {0, 1, 7, 8},
      {1, 2, 8, 9},
      {2, 3, 9, 10},
      {3, 4, 10, 11},
      {4, 5, 11, 12},
      {5, 6, 12, 13},
      {6, 1, 13, 8},
      //last two faces how to tel they should be 0 1 2 3 4 5 6 and  7 8 9 10 11 12 13 ?
      {0, 1, 2, 3},
      {7, 8, 9, 10},
      };

  vtkSmartPointer<vtkCellArray> heptagonFaces=
    vtkSmartPointer<vtkCellArray>::New();
  for (int i = 0; i < numberOfFaces; i++)
    {
    heptagonFaces->InsertNextCell(numberOfFaceVertices, heptagonPrismFace[i]);
    }

  vtkSmartPointer<vtkUnstructuredGrid> uGrid = vtkSmartPointer<vtkUnstructuredGrid>::New();
  uGrid->InsertNextCell(VTK_POLYHEDRON,
          numberOfVertices, heptagonPointsIds,
        numberOfFaces, heptagonFaces->GetPointer());
  uGrid->SetPoints(points);

vtkSmartPointer<vtkDataSetMapper> mapper =     vtkSmartPointer<vtkDataSetMapper>::New();
  mapper->SetInputConnection(uGrid->GetProducerPort());


  //add actor to render and stuff...

我如何获得类似图片的内容：

Answer 1

使用vtkLinearExtrusionFilter要容易得多。我写了一些c ++代码来生成带有可变边的多边形棱镜。我希望这会有所帮助：

    vtkSmartPointer<vtkVectorText> vecText = 
vtkSmartPointer<vtkVectorText>::New();
vecText->SetText("Text!");
vecText->Update();
vtkSmartPointer<vtkPoints> points =
vtkSmartPointer<vtkPoints>::New();
double Radius=1;
int NumberOfSides=7;
for (int i=0;i<NumberOfSides;i++)
    points->InsertNextPoint(Radius*cos((double)i*2*vtkMath::Pi()/NumberOfSides), Radius*sin((double)i*2*vtkMath::Pi()/NumberOfSides), 0.0); 
// Create the polygon
vtkSmartPointer<vtkPolygon> polygon =
vtkSmartPointer<vtkPolygon>::New();
polygon->GetPointIds()->SetNumberOfIds(NumberOfSides); 

for(int i=0;i<NumberOfSides;i++)
    polygon->GetPointIds()->SetId(i, i);

// Add the polygon to a list of polygons
vtkSmartPointer<vtkCellArray> polygons =
vtkSmartPointer<vtkCellArray>::New();
polygons->InsertNextCell(polygon);

// Create a PolyData
vtkSmartPointer<vtkPolyData> polygonPolyData =
vtkSmartPointer<vtkPolyData>::New();
polygonPolyData->SetPoints(points);
polygonPolyData->SetPolys(polygons);

// Apply linear extrusion 
vtkSmartPointer<vtkLinearExtrusionFilter> extrude = 
vtkSmartPointer<vtkLinearExtrusionFilter>::New();
extrude->SetInputData( polygonPolyData);
extrude->SetExtrusionTypeToNormalExtrusion();
extrude->SetVector(0, 0, 1 );
extrude->SetScaleFactor (2);
extrude->Update(); 
vtkSmartPointer<vtkRenderWindow> renderWindow = 
vtkSmartPointer<vtkRenderWindow>::New();
vtkSmartPointer<vtkPolyDataMapper> mapper=vtkSmartPointer<vtkPolyDataMapper>::New();
vtkSmartPointer<vtkActor> actor=vtkSmartPointer<vtkActor>::New();
mapper->SetInputData( extrude->GetOutput());
actor->SetMapper(mapper);
vtkSmartPointer<vtkRenderer> renderer=vtkSmartPointer<vtkRenderer>::New();
renderer->AddActor(actor);
renderWindow->AddRenderer(renderer);

vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =  vtkSmartPointer<vtkRenderWindowInteractor>::New();
renderWindow->SetInteractor( renderWindowInteractor);
renderWindow->Render(); 

我运行了代码并获得了七角形棱镜的三维形状：

Answer 2

由于没有七边形或八边形棱镜的定义，您必须手动定义所有面，然后将每个面添加到vtkUnstructuredGrid，例如检查这个八角形棱镜定义（这应该让你开始）：

            vtkPoints points = vtkPoints.New();
            //up
            points.InsertNextPoint(0.0, 0.0, 0.0 );//0
            points.InsertNextPoint(0.3, -0.5, 0.0);//1
            points.InsertNextPoint(0.6, -.8, 0.0);//2
            points.InsertNextPoint(0.7, -.9, 0.0);//3
            points.InsertNextPoint(0.8, -0.8, 0.0);//4
            points.InsertNextPoint(1.0, 0.0, 0.0);//5
            points.InsertNextPoint(1.0, 1.0, 0.0);//6
            points.InsertNextPoint(0.0, 1.0, 0.0);//7
            //down
            points.InsertNextPoint(0.0, 0.0, 1.0);//8
            points.InsertNextPoint(0.3, -0.5, 1.0);//9
            points.InsertNextPoint(0.6, -.8, 1.0);//10
            points.InsertNextPoint(0.7, -0.9, 1.0);//11
            points.InsertNextPoint(0.8, -0.8, 1.0);//12
            points.InsertNextPoint(1.0, 0.0, 1.0);//13
            points.InsertNextPoint(1.0, 1.0, 1.0);//14
            points.InsertNextPoint(0.0, 1.0, 1.0);//15
            vtkUnstructuredGrid ugrid = vtkUnstructuredGrid.New();
            int[] ptIds; IntPtr ptIdsPointer;
            //8 quad faces 
            ptIds = new int[] { 0, 1, 9, 8 }; ptIdsPointer = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(int)) * ptIds.Length); Marshal.Copy(ptIds, 0, ptIdsPointer, ptIds.Length); ugrid.InsertNextCell(9, ptIds.Length, ptIdsPointer); Marshal.FreeHGlobal(ptIdsPointer);
            ptIds = new int[] { 1, 2, 10, 9 }; ptIdsPointer = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(int)) * ptIds.Length); Marshal.Copy(ptIds, 0, ptIdsPointer, ptIds.Length); ugrid.InsertNextCell(9, ptIds.Length, ptIdsPointer); Marshal.FreeHGlobal(ptIdsPointer);
            ptIds = new int[] { 2, 3, 11, 10 }; ptIdsPointer = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(int)) * ptIds.Length); Marshal.Copy(ptIds, 0, ptIdsPointer, ptIds.Length); ugrid.InsertNextCell(9, ptIds.Length, ptIdsPointer); Marshal.FreeHGlobal(ptIdsPointer);
            ptIds = new int[] { 3, 4, 12, 11 }; ptIdsPointer = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(int)) * ptIds.Length); Marshal.Copy(ptIds, 0, ptIdsPointer, ptIds.Length); ugrid.InsertNextCell(9, ptIds.Length, ptIdsPointer); Marshal.FreeHGlobal(ptIdsPointer);
            ptIds = new int[] { 4, 5, 13, 12 }; ptIdsPointer = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(int)) * ptIds.Length); Marshal.Copy(ptIds, 0, ptIdsPointer, ptIds.Length); ugrid.InsertNextCell(9, ptIds.Length, ptIdsPointer); Marshal.FreeHGlobal(ptIdsPointer);
            ptIds = new int[] { 5, 6, 14, 13 }; ptIdsPointer = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(int)) * ptIds.Length); Marshal.Copy(ptIds, 0, ptIdsPointer, ptIds.Length); ugrid.InsertNextCell(9, ptIds.Length, ptIdsPointer); Marshal.FreeHGlobal(ptIdsPointer);
            ptIds = new int[] { 6, 7, 15, 14 }; ptIdsPointer = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(int)) * ptIds.Length); Marshal.Copy(ptIds, 0, ptIdsPointer, ptIds.Length); ugrid.InsertNextCell(9, ptIds.Length, ptIdsPointer); Marshal.FreeHGlobal(ptIdsPointer);
            ptIds = new int[] { 7, 0, 8, 15 }; ptIdsPointer = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(int)) * ptIds.Length); Marshal.Copy(ptIds, 0, ptIdsPointer, ptIds.Length); ugrid.InsertNextCell(9, ptIds.Length, ptIdsPointer); Marshal.FreeHGlobal(ptIdsPointer);
            //2 octagonal faces 
            ptIds = new int[] { 0, 1, 2, 3, 4, 5, 6, 7 }; ptIdsPointer = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(int)) * ptIds.Length); Marshal.Copy(ptIds, 0, ptIdsPointer, ptIds.Length); ugrid.InsertNextCell(9, ptIds.Length, ptIdsPointer); Marshal.FreeHGlobal(ptIdsPointer);
            ptIds = new int[] { 8, 9, 10, 11, 12, 13, 14, 15 }; ptIdsPointer = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(int)) * ptIds.Length); Marshal.Copy(ptIds, 0, ptIdsPointer, ptIds.Length); ugrid.InsertNextCell(9, ptIds.Length, ptIdsPointer); Marshal.FreeHGlobal(ptIdsPointer);
            ugrid.SetPoints(points);
            vtkGeometryFilter geometryFilter = vtkGeometryFilter.New();
            geometryFilter.SetInput(ugrid);
            vtkActor loActor = new vtkActor();
            vtkPolyDataMapper pdm = vtkPolyDataMapper.New();
            pdm.SetInputConnection(geometryFilter.GetOutputPort());
            loActor.SetMapper(pdm);
            loActor.GetProperty().SetPointSize(5);
            loActor.GetProperty().SetColor(.9, 0, 0);
            Renderer3D.AddActor(loActor);
            vtkIdFilter ids = new vtkIdFilter();
            ids.SetInputConnection(ugrid.GetProducerPort());
            ids.PointIdsOn();
            ids.CellIdsOn();
            ids.FieldDataOn();
            vtkLabeledDataMapper ldm = new vtkLabeledDataMapper();
            ldm.SetInputConnection(ids.GetOutputPort());
            ldm.SetLabelModeToLabelFieldData();
            vtkActor2D pointLabels = new vtkActor2D();

将导致：

Answer 3

我认为你可以使用vtkPolyhedron例如：

import vtk
import math

class Point:
    def __init__(self, x, y, z):
        self.x =float(x)
        self.y = float(y)
        self.z = float(z)
    def like_list(self):
        return [self.x,self.y,self.z]


def generate_points(n):
    l = []
    centre = Point(0.0,0.0,0.0)
    angle = (360.0/float(n))
    r_len = 1.0
    l.append(Point(1.0,0.0,0.0))
    for i in xrange(1,n):
        alpha = math.radians(float(i)*angle)
        x = r_len * math.cos(alpha)
        y = r_len * math.sin(alpha)
        l.append(Point(x, y, 0.0))
    #down face simple translate points on 1 up
    l2 = [Point(p.x,p.y,p.z + 1.0) for p in l]
    l.extend(l2)
    return l

def MakeHeptagonalPrism():
    p_list = generate_points(7) # 7 is a number of vertices in base of polyhedron
    points = vtk.vtkPoints()
    for p in p_list:
        points.InsertNextPoint(p.like_list())
    #You should fix list of faces if change number of vertices but 
    #I think it's posible to write aloritm to make it automaticaly
    heptagonalFace = [
        [0, 1, 2, 3, 4, 5, 6],
        [7, 8, 9, 10, 11, 12, 13],
        [0, 1, 8, 7],
        [1, 2, 9, 8],
        [2, 3, 10, 9],
        [3, 4, 11, 10],
        [4, 5, 12, 11],
        [5, 6, 13, 12],
        [6, 0, 7, 13]
        ]
    numberOfFaces = 9
    heptagonalFacesIdList = vtk.vtkIdList()
    # Number faces that make up the cell.
    heptagonalFacesIdList.InsertNextId(numberOfFaces)
    for face in heptagonalFace:
        # Number of points in the face == numberOfFaceVertices
        heptagonalFacesIdList.InsertNextId(len(face))
        # Insert the pointIds for that face.
        [heptagonalFacesIdList.InsertNextId(i) for i in face]

    uGrid = vtk.vtkUnstructuredGrid()
    uGrid.InsertNextCell(vtk.VTK_POLYHEDRON, heptagonalFacesIdList)
    uGrid.SetPoints(points)

    # Visualize
    mapper = vtk.vtkDataSetMapper()
    mapper.SetInput(uGrid)

    actor = vtk.vtkActor()
    actor.SetMapper(mapper)

    renderer = vtk.vtkRenderer()
    renderWindow = vtk.vtkRenderWindow()
    renderWindow.AddRenderer(renderer)
    renderWindowInteractor = vtk.vtkRenderWindowInteractor()
    renderWindowInteractor.SetRenderWindow(renderWindow)

    renderer.AddActor(actor)
    renderer.SetBackground(.2, .3, .4)

    renderWindow.Render()
    renderWindowInteractor.Start()


if __name__ == '__main__':
    MakeHeptagonalPrism()

仅仅是为了获取信息在我看来真的很棘手，但您也可以使用vtkCylinderSource从here取示并将分辨率更改为7 source.SetResolution(7.0)（它应该像棱镜一样绘制棱镜，但是它将是一个圆柱:)）

希望它会有所帮助。