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This article mainly introduces the method of attribute selection and cutting of Python-VTK implicit function. In daily operation, I believe that many people have doubts about the method of attribute selection and cutting of Python-VTK implicit function. The editor consulted all kinds of data and sorted out simple and easy-to-use operation methods. I hope it will be helpful for you to answer the doubts of "Python-VTK implicit function attribute selection and cutting method". Next, please follow the editor to study!

Foreword:

VTK, (visualizationtoolkit) is an open source free software system, mainly used for three-dimensional computer graphics, image processing and visualization. Vtk is designed and implemented on the basis of object-oriented principle. Its kernel is built with C++. It contains about 250000 lines of code, more than 2000 classes, and several conversion interfaces, so it is also free to use vtk through various languages of Java,Tcl/Tk and Python.

Using an implicit function to select or extract data means selecting units and points (and related attribute data) that are located within a specific area of the function. To determine whether the point x-y-z is in an area, we just need to calculate the point and check the coordinate symbols of the result. If all the points of the cell are in the area, the cell is in that area. Here, a combination of two ellipses is used to select voxels in the volume dataset. Note that extracting data usually changes the structure of the dataset. In this case, the input type is an image dataset and the output type is an unstructured grid dataset.

Function introduction:

VtkQuadricClustering is a class used to cut triangles to get an approximate geometry. Its input is vtkPolyData type data, can handle all types of polygonal meshes, its speed is very fast. It can quickly reduce the large grid model, and support grid fragment reduction (using startAppend, Append, endAppend methods), which can avoid loading the whole model into memory. For the large-scale network model, it has a good effect, but when the mesh becomes smaller, the triangulation effect is not very good, so it needs to be combined with other methods.

Vtk.vtkSampleFunction is an implicit function representation class in VTK, which can be used to sample surfaces point by point at equal intervals.

VtkShrinkFilter shrinks to form cells for any dataset of its centroid. The average position of the cell point is used as the center of mass of the calculation unit. The result of atrophy interrupting another cell. The output of this filter is the generic dataset type vtkUnstructuredGrid of.

Import vtkdef main (): colors = vtk.vtkNamedColors () ren1 = vtk.vtkRenderer () renWin = vtk.vtkRenderWindow () renWin.AddRenderer (ren1) iren = vtk.vtkRenderWindowInteractor () iren.SetRenderWindow (renWin) quadric = vtk.vtkQuadric () quadric.SetCoefficients (0.5,1,0.2,0,0.1,0,0.2,0,0) sample = vtk.vtkSampleFunction () sample.SetSampleDimensions (50,50) 50) sample.SetImplicitFunction (quadric) sample.ComputeNormalsOff () trans = vtk.vtkTransform () trans.Scale (1,0.5,0.5) sphere = vtk.vtkSphere () sphere.SetRadius (0.25) sphere.SetTransform (trans) trans2 = vtk.vtkTransform () trans2.Scale (0.25,0.5) Sphere2 = vtk.vtkSphere () sphere2.SetRadius (0.25) sphere2.SetTransform (trans2) booleanUnion = vtk.vtkImplicitBoolean () booleanUnion.AddFunction (sphere) booleanUnion.AddFunction (sphere2) booleanUnion.SetOperationType (0) # booleanUnion extract = vtk.vtkExtractGeometry () extract.SetInputConnection (sample.GetOutputPort ()) extract.SetImplicitFunction (booleanUnion) shrink = vtk.vtkShrinkFilter () shrink.SetInputConnection (extract.GetOutputPort () shrink .SetShrinkFactor = vtk.vtkDataSetMapper () dataMapper.SetInputConnection (shrink.GetOutputPort ()) dataActor = vtk.vtkActor () dataActor.SetMapper (dataMapper) # outline outline = vtk.vtkOutlineFilter () outline.SetInputConnection (sample.GetOutputPort ()) outlineMapper = vtk.vtkPolyDataMapper () outlineMapper.SetInputConnection (outline.GetOutputPort ()) outlineActor = vtk.vtkActor () outlineActor.SetMapper (outlineMapper) outlineActor.GetProperty (). SetColor (0) 0,0) # add actor to the window And set the size of the related window # ren1.AddActor (outlineActor) ren1.AddActor (dataActor) ren1.SetBackground (colors.GetColor3d ("SlateGray")) renWin.SetWindowName ('ExtractData') renWin.Render () ren1.GetActiveCamera (). Azimuth (30) ren1.GetActiveCamera (). Elevation (30) renWin.Render () iren.Start () if _ name__ = =' _ main__': main ()

The results are as follows:

At this point, the study of "Python-VTK implicit function attribute selection and cutting method" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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