/// <summary>
/// Returns the tangents between the active CircularArc3d instance complete circle and a point.
/// </summary>
/// <remarks>
/// Tangents start points are on the object to which this method applies, end points on the point passed as argument.
/// Tangents are always returned in the same order: the tangent on the left side of the line from the circular arc center
/// to the point before the one on the right side.
/// </remarks>
/// <param name="arc">The instance to which this method applies.</param>
/// <param name="pt">The Point3d to which tangents are searched</param>
/// <returns>An array of LineSegement3d representing the tangents (2) or null if there is none.</returns>
/// <exception cref="Autodesk.AutoCAD.Runtime.Exception">
/// eNonCoplanarGeometry is thrown if the objects do not lies on the same plane.</exception>
public static LineSegment3d[] GetTangentsTo(this CircularArc3d arc, Point3d pt)
{
// check if arc and point lies on the plane
Vector3d normal = arc.Normal;
Matrix3d WCS2OCS = Matrix3d.WorldToPlane(normal);
double elevation = arc.Center.TransformBy(WCS2OCS).Z;
if (Math.Abs(elevation - pt.TransformBy(WCS2OCS).Z) < Tolerance.Global.EqualPoint)
throw new Autodesk.AutoCAD.Runtime.Exception(
Autodesk.AutoCAD.Runtime.ErrorStatus.NonCoplanarGeometry);
Plane plane = new Plane(Point3d.Origin, normal);
Matrix3d OCS2WCS = Matrix3d.PlaneToWorld(plane);
CircularArc2d ca2d = new CircularArc2d(arc.Center.Convert2d(plane), arc.Radius);
LineSegment2d[] lines2d = ca2d.GetTangentsTo(pt.Convert2d(plane));
if (lines2d == null)
return null;
LineSegment3d[] result = new LineSegment3d[lines2d.Length];
for (int i = 0; i < lines2d.Length; i++)
{
LineSegment2d ls2d = lines2d[i];
result[i] = new LineSegment3d(ls2d.StartPoint.Convert3d(normal, elevation), ls2d.EndPoint.Convert3d(normal, elevation));
}
return result;
}
private Line getLine(LineSegment3d segment, Curve curve)
{
Vector3d vectorIsoline = segment.Direction.GetPerpendicularVector() * Commands.Options.DashLength;
if (IsNegate)
{
vectorIsoline = vectorIsoline.Negate();
}
Point3d ptEndIsoline = segment.MidPoint + vectorIsoline;
Line line = new Line(segment.MidPoint, ptEndIsoline);
line.Layer = curve.Layer;
line.LineWeight = curve.LineWeight;
line.Color = curve.Color;
line.Linetype = SymbolUtilityServices.LinetypeContinuousName;
return line;
}
public List<Line> GetLines(Curve curve)
{
List<Line> lines = new List<Line>();
if (curve is Polyline)
{
Polyline pl = (Polyline)curve;
for (int i = 0; i < pl.NumberOfVertices; i++)
{
SegmentType segmentType = pl.GetSegmentType(i);
if (segmentType == SegmentType.Line)
{
var lineSegment = pl.GetLineSegmentAt(i);
var line = getLine(lineSegment, curve);
lines.Add(line);
}
}
}
else if (curve is Line)
{
Line lineCurve = (Line)curve;
LineSegment3d segment = new LineSegment3d(lineCurve.StartPoint, lineCurve.EndPoint);
var line = getLine(segment, curve);
lines.Add(line);
}
return lines;
}
private double GetPolylineShape(LineSegment3d l1, LineSegment3d l2, Vector3d normal)
{
Vector3d v1 = l1.EndPoint - l1.StartPoint;
Vector3d v2 = l2.EndPoint - l2.StartPoint;
return v1.GetAngleTo(v2, normal);
}
public static void Breakatpoint()
{
Document acDoc = acApp.DocumentManager.MdiActiveDocument;
Database acDb = acDoc.Database;
Editor acEd = acDoc.Editor;
PromptSelectionResult psr = acEd.GetSelection();
if (psr.Status != PromptStatus.OK)
{
return;
}
foreach (ObjectId id in psr.Value.GetObjectIds())
{
using (Transaction acTrans = acDb.TransactionManager.StartTransaction())
{
BlockTable acBlkTbl;
acBlkTbl = acTrans.GetObject(acDb.BlockTableId,
OpenMode.ForRead) as BlockTable;
BlockTableRecord acBlkTblRec;
acBlkTblRec = acTrans.GetObject(acBlkTbl[BlockTableRecord.ModelSpace],
OpenMode.ForWrite) as BlockTableRecord;
Line line = (Line)acTrans.GetObject(id, OpenMode.ForRead);
PromptPointResult pr = acEd.GetPoint("Select break point");
if (pr.Status != PromptStatus.Cancel)
{
ObjectId objId;
Point3d pointPr = pr.Value;
//Test to ensure that point selected actually lies on the line
if (IsPointOnCurve(line, pointPr))
{
//create new line from selected line start point to point chosen
var lineseg = new LineSegment3d(line.StartPoint, pointPr);
var vec = lineseg.Direction.MultiplyBy(2).Negate();
Line line_seg1 = new Line(line.StartPoint, pointPr.Add(vec));
line_seg1.Layer = line.Layer;
objId = acBlkTblRec.AppendEntity(line_seg1);
acTrans.AddNewlyCreatedDBObject(line_seg1, true);
//create new line from point chosen to end point on selected line
lineseg = new LineSegment3d(pointPr, line.EndPoint);
vec = lineseg.Direction.MultiplyBy(2).Negate();
Line line_seg2 = new Line(pointPr.Subtract(vec), line.EndPoint);
line_seg2.Layer = line.Layer;
objId = acBlkTblRec.AppendEntity(line_seg2);
acTrans.AddNewlyCreatedDBObject(line_seg2, true);
//remove origionally selected line
Entity acEnt = acTrans.GetObject(id, OpenMode.ForWrite) as Entity;
acEnt.Erase();
acEnt.Dispose();
}
else
{
MessageBox.Show("Point chosen does not lie on the line selected");
}
}
else
{
return;
}
acTrans.Commit();
}
}
}