如何創建vtk七棱柱（具有4個頂點和7個頂點的2個面）

Question

在vtk中，您最多可以將一個六角棱柱單元添加到帶有InsertNextCell (int type, vtkIdType npts, vtkIdType *ptIds)的vtkUnstructuredGrid。這很好，但我想包括一個七邊形和八角形棱鏡到vtkUnstructuredGrid。細胞類型在VTK定義...

只是爲了澄清一些疑問，我與c#工作，但一個c++或python例子就足以將其翻譯爲c#。

回到問題，我先複製並稍微修改了代碼in this example獲得體素（8分和單元格類型= 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); 

這顯示正確的體素獲得：

但因爲我想一個七面體，我努力適應使用VTK_POLYHEDRON的想法，改變它告訴PF類型的細胞中添加行非結構網格

  unstructuredGrid1.InsertNextCell(11, 8, ptIdsPointer); 

至（42代表VTK_POLYHEDRON，11個代表VTK_VOXEL）和點= 14

  unstructuredGrid1.InsertNextCell(42, 14, ptIdsPointer); 

this example等。我triedsomething像C++，但我沒有得到任何結果

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... 

我怎麼會得到這樣的形象：

Answer 1

至於有一個七邊形也不八角棱鏡沒有定義，你必須手動定義所有面，然後每增加vtkUnstructuredGrid，例如檢查此八棱柱定義（這應該讓你開始）：

  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(); 

，這將導致：

Answer 2

我認爲你可以使用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() 

只是爲了信息，在我看來很麻煩，但你也可以使用vtkCylinderSource只取例如從here和更改分辨率到7 source.SetResolution(7.0)（它應該畫形狀的棱鏡，但它將是一個圓柱:)）

希望它會有幫助。

Answer 3

使用vtkLinearExtrusionFilter更容易。我寫了一些C++代碼來生成可變面的多邊形棱鏡。我希望這將有助於：

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(); 

我跑的代碼，並得到了七角柱這種3D形狀：