# PolygonIntersection

VTKExamples/Python/GeometricObjects/PolygonIntersection

Other Languages

See (Cxx), (CSharp)

### Code

PolygonIntersection.py

    #!/usr/bin/env python
    from __future__ import print_function

    import vtk

    def main():
        # Create a square in the x-y plane.
        points = vtk.vtkPoints()
        points.InsertNextPoint(0.0, 0.0, 0.0)
        points.InsertNextPoint(1.0, 0.0, 0.0)
        points.InsertNextPoint(1.0, 1.0, 0.0)
        points.InsertNextPoint(0.0, 1.0, 0.0)

        # Create the polygon
        polygon = vtk.vtkPolygon()
        polygon.GetPoints().DeepCopy(points)
        polygon.GetPointIds().SetNumberOfIds(4)  # The 4 corners of the square
        for i in range(4):
            polygon.GetPointIds().SetId(i, i)

        # Inputs
        p1 = [0.1, 0, -1.0]
        p2 = [0.1, 0, 1.0]
        tolerance = 0.001

        # Outputs
        t = vtk.mutable(0)  # Parametric coordinate of intersection (0 (corresponding to p1) to 1 (corresponding to p2))
        x = [0.0, 0.0, 0.0]
        pcoords = [0.0, 0.0, 0.0]
        subId = vtk.mutable(0)
        iD = polygon.IntersectWithLine(p1, p2, tolerance, t, x, pcoords, subId)

        print("intersected? ", 'Yes' if iD == 1 else 'No')
        print("intersection: ", x)

    if __name__ == '__main__':
        main()