VTK/Tutorials/TriangleGeometryOnly

This example writes the coordinates of the corners of a triangle to a vtp file. There is geometry (points), but there is no topology (vertices), so if you open this file in Paraview, you will not see anything. You can "glyph" the points to see them, but generally some type of topology exists. We will see topology in the next example.

<source lang="cpp">

1. include <iostream>
2. include <vector>

1. include "vtkCellArray.h"
2. include "vtkPoints.h"
3. include "vtkXMLPolyDataWriter.h"
4. include "vtkPolyData.h"

struct Point { double x,y,z; Point(const double xin, const double yin, const double zin) : x(xin), y(yin), z(zin) {} };

int main() { //setup points std::vector<Point> Coords; Coords.push_back(Point(-1.0, 1.0, 0.0)); Coords.push_back(Point(1.0, 1.0, 0.0)); Coords.push_back(Point(1.0, -1.0, 0.0));

vtkPoints* Points = vtkPoints::New();

for (unsigned int i = 0; i < Coords.size(); ++i ) { Point P = Coords[i]; Points->InsertNextPoint(P.x, P.y, P.z); }

vtkPolyData* polydata = vtkPolyData::New();

polydata->SetPoints(Points);

vtkXMLPolyDataWriter* writer = vtkXMLPolyDataWriter::New(); writer->SetFileName("Square.vtp"); writer->SetInput(polydata); writer->Write();

}</source>