// Return a MeshGeometry3D representing this mesh's wireframe.
public static MeshGeometry3D ToWireframe(this MeshGeometry3D mesh, double thickness)
{
// Make a mesh to hold the wireframe.
MeshGeometry3D wireframe = new MeshGeometry3D();
// Make a HashSet to keep track of edges
// that have already been added.
HashSet <Edge> already_added = new HashSet <Edge>();
// Loop through the mesh's triangles.
for (int triangle = 0; triangle < mesh.TriangleIndices.Count; triangle += 3)
{
// Get the triangle's corner indices.
int index1 = mesh.TriangleIndices[triangle];
int index2 = mesh.TriangleIndices[triangle + 1];
int index3 = mesh.TriangleIndices[triangle + 2];
Point3D point1 = mesh.Positions[index1];
Point3D point2 = mesh.Positions[index2];
Point3D point3 = mesh.Positions[index3];
// Make the triangle's three segments.
wireframe.AddEdge(already_added, point1, point2, thickness);
wireframe.AddEdge(already_added, point2, point3, thickness);
wireframe.AddEdge(already_added, point3, point1, thickness);
}
return(wireframe);
}
// Add an outline wireframe for a polygon.
public static void AddPolygonWireframe(this MeshGeometry3D mesh,
double thickness, params Point3D[] points)
{
// Make a HashSet to keep track of edges
// that have already been added.
HashSet <Edge> already_added = new HashSet <Edge>();
// Loop through the polygon's vertices.
for (int i = 0; i < points.Length - 1; i++)
{
mesh.AddEdge(already_added, points[i], points[i + 1], thickness);
}
mesh.AddEdge(already_added, points[points.Length - 1], points[0], thickness);
}
// Define the model.
private void DefineModel(Model3DGroup group)
{
// Axes.
MeshExtensions.AddAxes(group);
// Make the generator.
const int numPoints = 20;
const double tmin = 1.1 * Math.PI;
const double tmax = tmin + 1.8 * Math.PI;
Point3D[] generator = new Point3D[numPoints];
double t = tmin;
double dt = (tmax - tmin) / (numPoints - 1);
for (int i = 0; i < numPoints; i++)
{
generator[i] = new Point3D(1 + 0.5 * Math.Sin(t), 3 - t * 0.5, 0);
t += dt;
}
// Make the transformation.
const int numRot = 20;
const double dangle = 360.0 / numRot;
RotateTransform3D rot = D3.Rotate(D3.YVector(), D3.Origin, dangle);
// Make the surface of transformation.
MeshGeometry3D mesh1 = new MeshGeometry3D();
mesh1.AddTransformSurface(generator, rot, numRot,
false, false, true, true,
false);
group.Children.Add(mesh1.MakeModel(Brushes.LightBlue));
// Make a wireframe.
HashSet <Edge> edges = new HashSet <Edge>();
MeshGeometry3D mesh2 = new MeshGeometry3D();
mesh2.AddTransformSurface(generator, rot, numRot,
false, false, true, true,
false, edges, 0.02);
group.Children.Add(mesh2.MakeModel(Brushes.Blue));
// Display the generator.
edges = new HashSet <Edge>();
MeshGeometry3D mesh3 = new MeshGeometry3D();
for (int i = 1; i < numPoints; i++)
{
mesh3.AddEdge(edges, 0.1, generator[i - 1], generator[i]);
}
group.Children.Add(mesh3.MakeModel(Brushes.Black));
}
