private void TriangulateButton_OnClick(object sender, RoutedEventArgs e)
{
List <int> triangleIndices;
// We will manually create the triangle indices with Triangulator
// This way we can catch the FormatException in case the _points are not correct (for example if lines intersect each other)
// If we do not need to show the exception message we could simply call the CreateExtrudedMeshGeometry without triangleIndices as second parameter.
// Than in case the _points were not correct we would simply get null back.
// Triangulator takes a list of 2D points and connects them with creating triangles (it creates triangle indices that are declared as Int32Collection).
// If we would only need triangle indices, we could also use static Triangulate method, but we need IsClockwise property later
//triangleIndices = Ab3d.Utilities.Triangulator.Triangulate(_points);
// Adjust shape positions so that (0,0) is at the center of the area
// We also invert y so that y increased upwards (as the blue arrows shows) and not downwards as in Canvas coordinate system
var centeredShapePositions = InvertYAndCenterPoints(_shapePositions);
Ab3d.Utilities.Triangulator triangulator = new Ab3d.Utilities.Triangulator(centeredShapePositions);
try
{
triangleIndices = triangulator.CreateTriangleIndices();
}
catch (FormatException ex)
{
// Usually thrown when the polygon lines intersect each other
MessageBox.Show(ex.Message);
return;
}
Vector3D extrudeVector, shapeYVector3D;
bool isSuccess = GetExtrudeAndUpVectors(out extrudeVector, out shapeYVector3D);
if (!isSuccess)
{
return;
}
// Get the 3D vector for the positions x axis direction (upVector3D is direction of y axis)
Vector3D shapeXVector3D = Vector3D.CrossProduct(extrudeVector, shapeYVector3D);
if (shapeXVector3D.LengthSquared < 0.001)
{
MessageBox.Show("Cannot extrude shape because extrudeVector and shapeYVector are parallel and not perpendicular.");
return;
}
// Convert list of 2D positions into a list of 3D positions with specifying custom X axis and Y axis
Point3DCollection positions = Convert2DTo3DPositions(centeredShapePositions, shapeXVector3D, shapeYVector3D);
//for (int i = 0; i < _shapePositions.Count; i++)
// positions.Add(new Point3D(_shapePositions[i].X + xOffset, yOffset, _shapePositions[i].Y + zOffset));
var mesh = new MeshGeometry3D();
mesh.Positions = positions;
mesh.TriangleIndices = new Int32Collection(triangleIndices);
CreateGeometryModel(mesh);
_isExtrudedModelShown = false;
}
public ExtrudeAlongPathSample()
{
InitializeComponent();
// First prepare two 2D shapes:
var letterTShapePositions = new Point[]
{
new Point(5, 0),
new Point(-5, 0),
new Point(-5, 40),
new Point(-20, 40),
new Point(-20, 50),
new Point(20, 50),
new Point(20, 40),
new Point(5, 40),
};
var ellipsePositionList = new List <Point>();
for (int i = 0; i < 360; i += 20)
{
ellipsePositionList.Add(new Point(Math.Sin(i / 180.0 * Math.PI) * 20, Math.Cos(i / 180.0 * Math.PI) * 10));
}
// Now define a simple 3D path:
var extrudePath = new Point3D[]
{
new Point3D(0, 0, 0),
new Point3D(0, 90, 0),
new Point3D(-20, 110, 0),
new Point3D(-50, 130, 20),
new Point3D(-50, 130, 100),
};
// Create extruded models:
MeshGeometry3D extrudedMesh1 = Mesh3DFactory.CreateExtrudedMeshGeometry(
shapePositions: ellipsePositionList,
extrudePathPositions: extrudePath,
shapeYVector3D: new Vector3D(0, 0, -1),
isClosed: true,
isSmooth: true);
CreateGeometryModel(extrudedMesh1, offset: new Vector3D(-150, 0, -50), setBackMaterial: false);
var extrudedMesh2 = Mesh3DFactory.CreateExtrudedMeshGeometry(
shapePositions: ellipsePositionList,
extrudePathPositions: extrudePath,
shapeYVector3D: new Vector3D(0, 0, -1),
isClosed: false,
isSmooth: false);
// Because this mesh will not be closed, we will be able to see inside - so set the back material to dim gray.
CreateGeometryModel(extrudedMesh2, offset: new Vector3D(0, 0, -50), setBackMaterial: true);
// Until now we only provided the shape positions to the CreateExtrudedMeshGeometry.
// This method then triangulated the shape in case it was closed.
// Here we manually triangulate the shape and provide the shapeTriangleIndices to CreateExtrudedMeshGeometry:
var triangulator = new Ab3d.Utilities.Triangulator(letterTShapePositions);
// NOTE: CreateTriangleIndices can throw FormatException when the positions are not correctly defined (for example if the lines intersect each other).
List <int> triangleIndices = triangulator.CreateTriangleIndices();
MeshGeometry3D extrudedMesh = Mesh3DFactory.CreateExtrudedMeshGeometry(
shapePositions: letterTShapePositions,
shapeTriangleIndices: triangleIndices,
extrudePathPositions: extrudePath,
shapeYVector3D: new Vector3D(0, 0, -1),
isClosed: true,
isSmooth: false,
flipNormals: triangulator.IsClockwise); // If true than normals are flipped - used when positions are defined in a counter clockwise order
CreateGeometryModel(extrudedMesh, offset: new Vector3D(150, 0, -50), setBackMaterial: false);
}
