In this article, we discuss how to create a 3D Triangle in WPF. For that follow these steps.

Step 1: First we take a Button Control and ViewPort in our .xaml page like this:

<Grid>
 <Button Name="TriangleButton" Click="triangleButtonClick">Triangle</Button>
 <Viewport3D Name="MainViewPort" ClipToBounds="True">
 <Viewport3D.Camera>
 <PerspectiveCamera
FarPlaneDistance="100"
 LookDirection="-12,-11,-10"
 UpDirection="0,1,0"
 NearPlaneDistance="1"
Position="11,10,9"
FieldOfView="75" />
 </Viewport3D.Camera>
 <ModelVisual3D>
 <ModelVisual3D.Content>
 <DirectionalLight
Color="White"
Direction="-2,-3,-1" />
 </ModelVisual3D.Content>
 </ModelVisual3D>
 </Viewport3D>
 </Grid>

Step 2: After that, we take this namespace in our .cs page:

using System.Windows.Media.Media3D;

Step 3: After that, we declare a MeshPoint3D like this:

MeshGeometry3D mymesh = new MeshGeometry3D();

It is used to get the Positions Collection, TriangleIndices Collection and a Normals Collection.

Step 4: Now we create the three points of the triangle:

mymesh.Positions.Add(p0);
mymesh.Positions.Add(p1);
mymesh.Positions.Add(p2);

After that, we add the Normals and TriangleIndices in this:

mymesh.TriangleIndices.Add(0);
mymesh.TriangleIndices.Add(1);
mymesh.TriangleIndices.Add(2);
Vector3D Normal = CalculateTraingleNormal(p0, p1, p2);
mymesh.Normals.Add(Normal);
mymesh.Normals.Add(Normal);
mymesh.Normals.Add(Normal);

After that, we add the Normal Vectors, which is used for the Mesh Points like this:

Vector3D Normal = CalculateTraingleNormal(p0, p1, p2);
mymesh.Normals.Add(Normal);
mymesh.Normals.Add(Normal);
mymesh.Normals.Add(Normal);

Here we take a function CalculateTriangleNormal; it is used to take the triangle indices, which we can get by the CrossProduct method of the Vector3D Structure.

Step 5: After that we add a DiffuseMaterial and set its color BlueViolet like this:

Material Material = new DiffuseMaterial(
new SolidColorBrush(Colors.BlueViolet));
GeometryModel3D model = new GeometryModel3D(
mymesh, Material);
Model3DGroup Group = new Model3DGroup();
Group.Children.Add(model);
 return Group;

Step 6: Now we write the function CalculateTriangleNormal:

private Vector3D CalculateTraingleNormal(Point3D p0, Point3D p1, Point3D p2)

{
Vector3D v0 = new Vector3D(
p1.X - p0.X, p1.Y - p0.Y, p1.Z - p0.Z);
Vector3D v1 = new Vector3D(
p2.X - p1.X, p2.Y - p1.Y, p2.Z - p1.Z);
return Vector3D.CrossProduct(v0, v1);
}

Step 7: Now we write the code for the Click event of the Button (TriangleButton):

private void triangleButtonClick(object sender, RoutedEventArgs e)

{
Model3DGroup triangle = new Model3DGroup();
Point3D p0 = new Point3D(0, 0, 0);
Point3D p1 = new Point3D(5, 0, 0);
Point3D p2 = new Point3D(5, 0, 5);
Point3D p3 = new Point3D(0, 0, 5);
Point3D p4 = new Point3D(0, 5, 0);
Point3D p5 = new Point3D(5, 5, 0);
Point3D p6 = new Point3D(5, 5, 5);

triangle.Children.Add(CreateTriangleModel(p1, p4, p3));
triangle.Children.Add(CreateTriangleModel(p1, p4, p6));

triangle.Children.Add(CreateTriangleModel(p3, p1, p6));

ModelVisual3D Model = new ModelVisual3D();
Model.Content = triangle;
this.MainViewPort.Children.Add(Model);
}

The Output will Be:

WPF.jpg