public override void OnDraw(GeometryBuilder dc)
{
dc.Clear();
// Define the basic points for drawing
Point3d pnt1 = _pnt1;
Point3d pnt2 = new Point3d(_pnt2.X, pnt1.Y, 0);
Point3d pnt3 = new Point3d(pnt2.X, pnt1.Y + 150, 0);
Point3d pnt4 = new Point3d(pnt1.X, pnt3.Y, 0);
// Set the color to ByObject value
dc.Color = McDbEntity.ByObject;
Vector3d hvec = new Vector3d(0, 0, _h);
// Draw the upper and lower sides
dc.DrawPolyline(new Point3d[] { pnt1, pnt2, pnt3, pnt4, _pnt1 });
dc.DrawPolyline(new Point3d[] { _pnt1.Add(hvec),
pnt2.Add(hvec), pnt3.Add(hvec), pnt4.Add(hvec), pnt1.Add(hvec) });
// Draw the edges
dc.DrawLine(pnt1, pnt1.Add(hvec));
dc.DrawLine(pnt2, pnt2.Add(hvec));
dc.DrawLine(pnt3, pnt3.Add(hvec));
dc.DrawLine(pnt4, pnt4.Add(hvec));
// Create contours for the front and rear sides and hatch them
// In this demo, we hatch only two sides, you can tailor the others yourself
List <Polyline3d> c1 = new List <Polyline3d>();
c1.Add(new Polyline3d(
new List <Point3d>()
{
pnt1, pnt1.Add(hvec), pnt2.Add(hvec), pnt2, pnt1,
}));
dc.DrawGeometry(new Hatch(c1, "BRICK", 0, 20, false, HatchStyle.Normal, PatternType.PreDefined, 30), 1);
List <Polyline3d> c2 = new List <Polyline3d>();
c2.Add(new Polyline3d(
new List <Point3d>()
{
pnt4, pnt4.Add(hvec), pnt3.Add(hvec), pnt3, pnt4,
}));
dc.DrawGeometry(new Hatch(c2, "BRICK", 0, 20, false, HatchStyle.Normal, PatternType.PreDefined, 30), 1);
}