wpf Viewport3d.GeometryModel3D.LinesCollec

Question

hi.
I want to add an ObservableCollection of Lines and ObservableCollection of arcsegment to Viewport3d.
the goal is to draw arcs based on the Lines so whenever line.x/line.y updated it automatically updates the arcs,
however my question is not about how to draw arcs or lines my question is how to add an ObservableCollection of Lines to Viewport3d.
thanks in advance, any help would be appreciated.

I'm using c#, wpfCore3.1, MS VS2019.

Answer 1

Hi, if you want see line you must create triangles. Try following code:

  <Window.DataContext>  
    <local:ViewModel/>  
  </Window.DataContext>  
  
  
    <Viewport3D>  
      <Viewport3D.Camera>  
        <PerspectiveCamera Position="-10,20,10" LookDirection="40,-40,-40" UpDirection="0,0,1"/>  
      </Viewport3D.Camera>  
      <ModelVisual3D Content="{Binding MGroup}"/>  
    </Viewport3D>  
  
  
  public class ViewModel  
Hi, if you want see line you must create triangles. try following code:  
  
  {  
    public Model3DGroup MGroup { get => GetData(); }  
  
    private ObservableCollection<Line> col = new ObservableCollection<Line>();  
  
    private Model3DGroup GetData()  
    {  
      // collection of lines  
      Point pt1 = new Point(0, 0);  
      Point pt2 = new Point(10, 0);  
      for (int i = 0; i < 10; i++) col.Add(new Line() { X1 = pt1.X, X2 = pt2.X, Y1 = pt1.Y + i, Y2 = pt2.Y + i });  
      // create ModelGroup  
      Model3DGroup gr = new Model3DGroup();  
      gr.Children.Add(new DirectionalLight(Colors.White, new Vector3D(-1, -1, -3)));  
      foreach (var item in col)  
      {  
        GeometryModel3D mod = AddLine(new Point3D(item.X1, item.Y1, 0), new Point3D(item.X2, item.Y2, 0));  
        gr.Children.Add(mod);  
      }  
      return gr;  
    }  
  
    private GeometryModel3D AddLine(Point3D startPoint, Point3D endPoint)  
    {  
      var material = new DiffuseMaterial(new SolidColorBrush(Colors.Red));  
      var mesh = new MeshGeometry3D();  
      mesh.Positions.Add(startPoint);  
      mesh.Positions.Add(endPoint);  
      mesh.Positions.Add(new Point3D(startPoint.X, startPoint.Y + .1, startPoint.Z));  
      mesh.Positions.Add(new Point3D(endPoint.X, endPoint.Y + .1, endPoint.Z));  
      mesh.TriangleIndices.Add(0);  
      mesh.TriangleIndices.Add(1);  
      mesh.TriangleIndices.Add(3);  
      mesh.TriangleIndices.Add(3);  
      mesh.TriangleIndices.Add(2);  
      mesh.TriangleIndices.Add(0);  
      return new GeometryModel3D(mesh, material);  
    }  
  }  
  
  public class MyViewPort  
  {  
    private Viewport3D _vPort;  
    public Viewport3D VPort  
    {  
      get => this._vPort;  
      set  
      {  
        if (this._vPort == null)  
        {  
          this._vPort = value;  
          this._vPort.MouseDown += _vPort_MouseDown;  
          this._vPort.MouseMove += _vPort_MouseMove;  
          this._vPort.MouseUp += _vPort_MouseUp;  
          this._vPort.Loaded += _vPort_Loaded;  
        }  
      }  
    }  
  
    private AxisAngleRotation3D rot = new AxisAngleRotation3D(new Vector3D(0, 2, 0), 0);  
    private void _vPort_Loaded(object sender, RoutedEventArgs e)  
    {  
      var mod = this._vPort.Children[0] as ModelVisual3D;  
      mod.Transform = new RotateTransform3D(rot);  
    }  
  
    private Point pt = new Point(double.NaN, double.NaN);  
    private void _vPort_MouseDown(object sender, MouseButtonEventArgs e) => pt = e.GetPosition(this._vPort);  
    private void _vPort_MouseMove(object sender, MouseEventArgs e)  
    {  
      if (!double.IsNaN(pt.X))  
      {  
        Point pt1 = e.GetPosition(this._vPort);  
        double ang = pt1.X - pt.X;  
        rot.Angle = ang;  
      }  
    }  
    private void _vPort_MouseUp(object sender, MouseButtonEventArgs e) => pt = new Point(double.NaN, double.NaN);  
  }