Subdivision
Repository source: Subdivision
Description¶
In this example a mesh is read from a file and then subdivided using linear subdivision. The SetNumberOfSubdivisions(n) function controls how many times the mesh is subdivided. For each n, the number of triangles will increase by approximately a factor of 4. For example, if n=2, the number of triangles in the resulting mesh will be 16x the number of triangles in the original mesh.
Different types of subdivisions can be obtained by replacing [vtkLinearSubdivisionFilter](https://www.vtk.org/doc/nightly/html/classvtkLinearSubdivisionFilter.html) with either [vtkLoopSubdivisionFilter](https://www.vtk.org/doc/nightly/html/classvtkLoopSubdivisionFilter.html) or [vtkButterflySubdivisionFilter](https://www.vtk.org/doc/nightly/html/classvtkButterflySubdivisionFilter.html).
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 must define the preprocessor directive VTK_MAJOR_VERSION_5.
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Code¶
Subdivision.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 {
Subdivision(null); // you may provide a full path to a *.vtu file
}
catch(Exception ex) {
MessageBox.Show(ex.Message, "Exception", MessageBoxButtons.OK);
}
}
private void Subdivision(string filePath) {
vtkPolyData originalMesh;
if(filePath != null) {
vtkXMLPolyDataReader reader = vtkXMLPolyDataReader.New();
reader.SetFileName(filePath);
// Subdivision filters only work on triangles
vtkTriangleFilter triangles = vtkTriangleFilter.New();
triangles.SetInputConnection(reader.GetOutputPort());
triangles.Update();
originalMesh = triangles.GetOutput();
}
else {
vtkSphereSource sphereSource = vtkSphereSource.New();
sphereSource.Update();
originalMesh = sphereSource.GetOutput();
}
Debug.WriteLine("Before subdivision");
Debug.WriteLine(" There are " + originalMesh.GetNumberOfPoints()
+ " points.");
Debug.WriteLine(" There are " + originalMesh.GetNumberOfPolys()
+ " triangles.");
int numberOfViewports = 3;
vtkRenderWindow renderWindow = renderWindowControl1.RenderWindow;
this.Size = new System.Drawing.Size(200 * numberOfViewports + 12, 252);
this.Text += " - Subdivision";
Random rnd = new Random(2);
int numberOfSubdivisions = 2;
// Create one text property for all
vtkTextProperty textProperty = vtkTextProperty.New();
textProperty.SetFontSize(14);
textProperty.SetJustificationToCentered();
for(int i = 0; i < numberOfViewports; i++) {
// Note: Here we create a superclass pointer (vtkPolyDataAlgorithm) so that we can easily instantiate different
// types of subdivision filters. Typically you would not want to do this, but rather create the pointer to be the type
// filter you will actually use, e.g.
// <vtkLinearSubdivisionFilter> subdivisionFilter = <vtkLinearSubdivisionFilter>.New();
vtkPolyDataAlgorithm subdivisionFilter;
switch(i) {
case 0:
subdivisionFilter = vtkLinearSubdivisionFilter.New();
( (vtkLinearSubdivisionFilter)subdivisionFilter ).SetNumberOfSubdivisions(numberOfSubdivisions);
break;
case 1:
subdivisionFilter = vtkLoopSubdivisionFilter.New();
( (vtkLoopSubdivisionFilter)subdivisionFilter ).SetNumberOfSubdivisions(numberOfSubdivisions);
break;
case 2:
subdivisionFilter = vtkButterflySubdivisionFilter.New();
( (vtkButterflySubdivisionFilter)subdivisionFilter ).SetNumberOfSubdivisions(numberOfSubdivisions);
break;
default:
subdivisionFilter = vtkLinearSubdivisionFilter.New();
( (vtkLinearSubdivisionFilter)subdivisionFilter ).SetNumberOfSubdivisions(numberOfSubdivisions);
break;
}
#if VTK_MAJOR_VERSION_5
subdivisionFilter.SetInputConnection(originalMesh.GetProducerPort());
#else
subdivisionFilter.SetInputData(originalMesh);
#endif
subdivisionFilter.Update();
vtkRenderer renderer = vtkRenderer.New();
renderWindow.AddRenderer(renderer);
renderer.SetViewport((float)i / numberOfViewports, 0, (float)( i + 1 ) / numberOfViewports, 1);
renderer.SetBackground(.2 + rnd.NextDouble() / 8, .3 + rnd.NextDouble() / 8, .4 + rnd.NextDouble() / 8);
vtkTextMapper textMapper = vtkTextMapper.New();
vtkActor2D textActor = vtkActor2D.New();
textMapper.SetInput(subdivisionFilter.GetClassName());
textMapper.SetTextProperty(textProperty);
textActor.SetMapper(textMapper);
textActor.SetPosition(100, 16);
//Create a mapper and actor
vtkPolyDataMapper mapper = vtkPolyDataMapper.New();
mapper.SetInputConnection(subdivisionFilter.GetOutputPort());
vtkActor actor = vtkActor.New();
actor.SetMapper(mapper);
renderer.AddActor(actor);
renderer.AddActor(textActor);
renderer.ResetCamera();
}
renderWindow.Render();
}
}
}