Question

我想要显示纹理的表面。我希望三角形边界在表面上以不同的颜色可见（比如红色）。我从vtk代码示例中找到了以下代码，但它不显示三角形边界，而是显示填充的三角形。

   import vtk

   # create a rendering window and renderer
   ren = vtk.vtkRenderer()
   renWin = vtk.vtkRenderWindow()
   renWin.AddRenderer(ren)

   # create a renderwindowinteractor
   iren = vtk.vtkRenderWindowInteractor()
   iren.SetRenderWindow(renWin)

   # create points
   points = vtk.vtkPoints()
   points.InsertNextPoint(1.0,0.0,0.0)
   points.InsertNextPoint(0.0,0.0,0.0)
   points.InsertNextPoint(0.0,1.0,0.0)

   triangle = vtk.vtkTriangle()
   triangle.GetPointIds().SetId(0,0)
   triangle.GetPointIds().SetId(1,1)
   triangle.GetPointIds().SetId(2,2)

   triangles = vtk.vtkCellArray()
   triangles.InsertNextCell(triangle)

   # polydata object
   trianglePolyData = vtk.vtkPolyData()
   trianglePolyData.SetPoints( points )
   trianglePolyData.SetPolys( triangles )

   # mapper
   mapper = vtk.vtkPolyDataMapper()
   mapper.SetInput(trianglePolyData)

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

   # assign actor to the renderer
   ren.AddActor(actor)

   # enable user interface interactor
   iren.Initialize()
   renWin.Render()
   iren.Start()

任何人都可以告诉我如何只显示具有特定颜色边界的三角形。

理想情况下，我想在纹理表面上显示三角形。我的数据由三角形组成。也可能使得给予vtk的三角形的顶点可见。

我在python中编码。

非常感谢

Answer 1

您需要从vtkPolyData对象中提取边缘：

edges = vtk.vtkExtractEdges()
edges.SetInput(trianglePolyData)
edge_mapper = vtk.vtkPolyDataMapper()
edge_mapper.SetInput(edges.GetOutput())

edge_actor = vtk.vtkActor()
edge_actor.SetMapper(edge_mapper)
edge_actor.GetProperty().SetColor(1,0,0)

ren.AddActor(edge_actor)

vtk.vtkPolyDataMapper().SetResolveCoincidentTopologyToPolygonOffset()

首先，您必须通过vtkExtractEdges过滤器提取边缘。您将该过滤器的结果映射到vtkPolyData对象，并为该数据构造一个actor。然后我们通过直接修改actor将网格的颜色设置为红色。

对vtk.vtkPolyDataMapper().SetResolveCoincidentTopologyToPolygonOffset()的调用可以防止边缘与曲面发生冲突（由于z缓冲区精度问题，两个几何对象重合并且撕裂相互穿过）。

为了完整起见，这是完整的代码：

import vtk

# create a rendering window and renderer
ren = vtk.vtkRenderer()
renWin = vtk.vtkRenderWindow()
renWin.AddRenderer(ren)

# create a renderwindowinteractor
iren = vtk.vtkRenderWindowInteractor()
iren.SetRenderWindow(renWin)

# create points
points = vtk.vtkPoints()
points.InsertNextPoint(1.0,0.0,0.0)
points.InsertNextPoint(0.0,0.0,0.0)
points.InsertNextPoint(0.0,1.0,0.0)

triangle = vtk.vtkTriangle()
triangle.GetPointIds().SetId(0,0)
triangle.GetPointIds().SetId(1,1)
triangle.GetPointIds().SetId(2,2)

triangles = vtk.vtkCellArray()
triangles.InsertNextCell(triangle)

# polydata object
trianglePolyData = vtk.vtkPolyData()
trianglePolyData.SetPoints( points )
trianglePolyData.SetPolys( triangles )

# mapper
mapper = vtk.vtkPolyDataMapper()
mapper.SetInput(trianglePolyData)

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

# assign actor to the renderer
ren.AddActor(actor)

#++++++++++++++++++++++++++++++++++++++++++++++++
# Get the edges from the mesh
edges = vtk.vtkExtractEdges()
edges.SetInput(trianglePolyData)
edge_mapper = vtk.vtkPolyDataMapper()
edge_mapper.SetInput(edges.GetOutput())

# Make an actor for those edges    
edge_actor = vtk.vtkActor()
edge_actor.SetMapper(edge_mapper)

# Make the actor red (there are other ways of doing this also)
edge_actor.GetProperty().SetColor(1,0,0)

ren.AddActor(edge_actor)

# Avoid z-buffer fighting
vtk.vtkPolyDataMapper().SetResolveCoincidentTopologyToPolygonOffset()
#------------------------------------------------

# enable user interface interactor
iren.Initialize()
renWin.Render()
iren.Start()

如何在vtk中仅在纹理表面上显示三角形边界？

1 个答案: