Draw (2D) Polygon with given 3D-Vertices and Transformation with VTK - drawing

Question

I have some 3d models and I want to display each face of the model seperately. For each face, I have a list of the vertices (as pcl::PointCloud), the Translation vector (as Eigen::Vector3f) and the Rotation Matrix (as Eigen::Quaternionf). The faces can have different shapes. It will be rectangular, round (n-verts polygon) and trapezial.
For the rectangular faces, I used vtkCubeSource so far and it works good. For the round faces, I could maybe use vtkCylinderSource. For trapezial faces, I didn't found a solution so far.
The best would be a class like vtkPolyLineSource, where I just need a list of vertices for any polygons. But as far as I see, vtkPolyLineSource would just draw the the line and don't fill the polynom with a color.
Is there a way to draw a polygon into 3d-space with vtk? Since it is possible to directly draw a 3d-model from a file, I think there should be a method for drawing a model (or just one face), but I couldn't find it so far. That's my first contact with VTK, so I think I just overlooked the right classes.
One reason why I don't just load a model-file is, that I need the faces in different colors and opacitys (defiend at runtime).

Answer 1

Use vtkPolygon
vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();
// ... fill in your points with n points
// Create the polygon
vtkSmartPointer<vtkPolygon> polygon = vtkSmartPointer<vtkPolygon>::New();
polygon->GetPointIds()->SetNumberOfIds(n);
for (int j = 0; j < n; j++)
{
polygon->GetPointIds()->SetId(j, j);
}
// Add the polygon to a list of polygons
vtkSmartPointer<vtkCellArray> polygons = vtkSmartPointer<vtkCellArray>::New();
polygons->InsertNextCell(polygon);
// Create a PolyData
vtkPolyData* polygonPolyData = vtkPolyData::New();
polygonPolyData->SetPoints(points);
polygonPolyData->SetPolys(polygons);
// create mapper and actor using this polydata - the usual stuff