# CapClip

VTKExamples/CSharp/Meshes/CapClip

### Description

This example shows how to generate a "cap" on a clipped polydata. It uses a clever trick to convert polylines into polygons. If a polydata file (.vtp) is provided, it will cap it. Otherwise it caps a clipped sphere.

A tutorial on how to setup a Windows Forms Application utilizing ActiViz.NET can be found here: Setup a Windows Forms Application to use ActiViz.NET
Note: As long as ActiViz.NET is not build with VTK version 6.0 or higher you have to define the preprocessor directive VTK_MAJOR_VERSION_5.

### Code

CapClip.cs

    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Windows.Forms;
    using System.Diagnostics;

    using Kitware.VTK;

    namespace ActiViz.Examples {
       public partial class Form1 : Form {
          public Form1() {
             InitializeComponent();
          }

          private void renderWindowControl1_Load(object sender, EventArgs e) {
             try {
                CapClip(null);
             }
             catch(Exception ex) {
                MessageBox.Show(ex.Message, "Exception", MessageBoxButtons.OK);
             }
          }

          private void CapClip(string filePath) {
             // PolyData to process
             vtkPolyData polyData;

             if(filePath != null) {
                vtkXMLPolyDataReader reader = vtkXMLPolyDataReader.New();
                reader.SetFileName(filePath);
                reader.Update();
                polyData = reader.GetOutput();
             }
             else {
                // Create a sphere
                vtkSphereSource sphereSource = vtkSphereSource.New();
                sphereSource.SetThetaResolution(20);
                sphereSource.SetPhiResolution(11);

                vtkPlane plane = vtkPlane.New();
                plane.SetOrigin(0, 0, 0);
                plane.SetNormal(1.0, -1.0, -1.0);

                vtkClipPolyData clipper = vtkClipPolyData.New();
                clipper.SetInputConnection(sphereSource.GetOutputPort());
                clipper.SetClipFunction(plane);
                clipper.SetValue(0);
                clipper.Update();

                polyData = clipper.GetOutput();
             }

             vtkDataSetMapper clipMapper = vtkDataSetMapper.New();
    #if VTK_MAJOR_VERSION_5
             clipMapper.SetInput(polyData);
    #else
             clipMapper.SetInputData(polyData);
    #endif

             vtkActor clipActor = vtkActor.New();
             clipActor.SetMapper(clipMapper);
             clipActor.GetProperty().SetColor(1.0000, 0.3882, 0.2784);
             clipActor.GetProperty().SetInterpolationToFlat();

             // Now extract feature edges
             vtkFeatureEdges boundaryEdges = vtkFeatureEdges.New();
    #if VTK_MAJOR_VERSION_5
             boundaryEdges.SetInput(polyData);
    #else
             boundaryEdges.SetInputData(polyData);
    #endif
             boundaryEdges.BoundaryEdgesOn();
             boundaryEdges.FeatureEdgesOff();
             boundaryEdges.NonManifoldEdgesOff();
             boundaryEdges.ManifoldEdgesOff();

             vtkStripper boundaryStrips = vtkStripper.New();
             boundaryStrips.SetInputConnection(boundaryEdges.GetOutputPort());
             boundaryStrips.Update();

             // Change the polylines into polygons
             vtkPolyData boundaryPoly = vtkPolyData.New();
             boundaryPoly.SetPoints(boundaryStrips.GetOutput().GetPoints());
             boundaryPoly.SetPolys(boundaryStrips.GetOutput().GetLines());

             vtkPolyDataMapper boundaryMapper = vtkPolyDataMapper.New();
    #if VTK_MAJOR_VERSION_5
             boundaryMapper.SetInput(boundaryPoly);
    #else
             boundaryMapper.SetInputData(boundaryPoly);
    #endif

             vtkActor boundaryActor = vtkActor.New();
             boundaryActor.SetMapper(boundaryMapper);
             boundaryActor.GetProperty().SetColor(0.8900, 0.8100, 0.3400);
             // get a reference to the renderwindow of our renderWindowControl1
             vtkRenderWindow renderWindow = renderWindowControl1.RenderWindow;
             // renderer
             vtkRenderer renderer = renderWindow.GetRenderers().GetFirstRenderer();
             // set background color
             renderer.SetBackground(.2, .3, .4);
             // add our actor to the renderer
             renderer.AddActor(clipActor);
             renderer.AddActor(boundaryActor);
             // Generate an interesting view
             //
             renderer.ResetCamera();
             renderer.GetActiveCamera().Azimuth(30);
             renderer.GetActiveCamera().Elevation(30);
             renderer.GetActiveCamera().Dolly(1.2);
             renderer.ResetCameraClippingRange();
          }
       }
    }