DeformPointSet

VTKEx/Python/Meshes/DeformPointSet

Description

An example that shows how to use the vtkDeformPointSet filter to deform a sphere with arbitrary polydata. This example uses a vtkSphereSource to generate polydata to use, however any polydata could be used, including stl files.

Other languages

See (Cxx)

Question

If you have a simple question about this example contact us at VTKExProject If your question is more complex and may require extended discussion, please use the VTK Discourse Forum

Code

DeformPointSet.py

import vtk


def main():
    colors = vtk.vtkNamedColors()

    # Set the background color.
    colors.SetColor("bkg", [0.2, 0.3, 0.4, 1.0])

    # Create a sphere to deform
    sphere = vtk.vtkSphereSource()
    sphere.SetThetaResolution(51)
    sphere.SetPhiResolution(17)
    sphere.Update()
    bounds = sphere.GetOutput().GetBounds()

    # Create a filter to color the sphere
    ele = vtk.vtkElevationFilter()
    ele.SetInputConnection(sphere.GetOutputPort())
    ele.SetLowPoint(0,0,-0.5);
    ele.SetHighPoint(0,0,0.5);
    ele.SetLowPoint((bounds[1] + bounds[0]) / 2.0,
                    (bounds[3] + bounds[2]) / 2.0,
                    -bounds[5]);
    ele.SetHighPoint((bounds[1] + bounds[0]) / 2.0,
                     (bounds[3] + bounds[2]) / 2.0,
                     bounds[5]);
    ele.Update()

    # Create a mesh to deform the sphere
    pts = vtk.vtkPoints()
    pts.SetNumberOfPoints(6)
    pts.SetPoint(0,
                 bounds[0] - 0.1 * (bounds[1] - bounds[0]),
                 (bounds[3] + bounds[2]) / 2.0,
                 (bounds[5] + bounds[4]) / 2.0)
    pts.SetPoint(1,
                 bounds[1] + 0.1 * (bounds[1] - bounds[0]),
                 (bounds[3] + bounds[2]) / 2.0,
                 (bounds[5] + bounds[4]) / 2.0)
    pts.SetPoint(2,
                 (bounds[1] + bounds[0]) / 2.0,
                 bounds[2] - 0.1 * (bounds[3] - bounds[2]),
                 (bounds[5] + bounds[4]) / 2.0)
    pts.SetPoint(3,
                 (bounds[1] + bounds[0]) / 2.0,
                 bounds[3] + 0.1 * (bounds[3] - bounds[2]),
                 (bounds[5] + bounds[4]) / 2.0)
    pts.SetPoint(4,
                 (bounds[1] + bounds[0]) / 2.0,
                 (bounds[3] + bounds[2]) / 2.0,
                 bounds[4] - 0.1 * (bounds[5] - bounds[4]))
    pts.SetPoint(5,
                 (bounds[1] + bounds[0]) / 2.0,
                 (bounds[3] + bounds[2]) / 2.0,
                 bounds[5] + 0.1 * (bounds[5] - bounds[4]))
    tris = vtk.vtkCellArray()

    cells = [[2, 0, 4], [1, 2, 4], [3, 1, 4], [0, 3, 4], [0, 2, 5], [2, 1, 5], [1, 3, 5], [3, 0, 5]]

    for cell in cells:
        tris.InsertNextCell(3)
        for c in cell:
            tris.InsertCellPoint(c)

    pd = vtk.vtkPolyData()
    pd.SetPoints(pts)
    pd.SetPolys(tris)

    meshMapper = vtk.vtkPolyDataMapper()
    meshMapper.SetInputData(pd)
    meshActor = vtk.vtkActor()
    meshActor.SetMapper(meshMapper)
    meshActor.GetProperty().SetRepresentationToWireframe()
    meshActor.GetProperty().SetColor(colors.GetColor3d("Black"))

    deform = vtk.vtkDeformPointSet()
    deform.SetInputData(ele.GetOutput())
    deform.SetControlMeshData(pd)
    deform.Update()

    controlPoint = pts.GetPoint(5)
    pts.SetPoint(5, controlPoint[0],
                 controlPoint[1],
                 bounds[5] + .8 * (bounds[5] - bounds[4]))
    pts.Modified()

    polyMapper = vtk.vtkPolyDataMapper()
    polyMapper.SetInputConnection(deform.GetOutputPort())
    polyActor = vtk.vtkActor()
    polyActor.SetMapper(polyMapper)

    renderer = vtk.vtkRenderer()
    renWin = vtk.vtkRenderWindow()
    renWin.AddRenderer(renderer)
    iren = vtk.vtkRenderWindowInteractor()
    iren.SetRenderWindow(renWin)

    renderer.AddActor(polyActor)
    renderer.AddActor(meshActor)

    renderer.GetActiveCamera().SetPosition(1,1,1)
    renderer.ResetCamera()
    renderer.SetBackground(colors.GetColor3d("bkg"))

    renWin.SetSize(300,300)
    renWin.Render()

    iren.Start()

if __name__ == '__main__':
    main()