Using vectors, the line is easy, so have a go at adding that
[CommandMethod("MultiLine")]
public void MultiLine()
{
Document doc = acadApp.DocumentManager.MdiActiveDocument;
Editor ed = doc.Editor;
Database db = HostApplicationServices.WorkingDatabase;
Matrix3d ucs = ed.CurrentUserCoordinateSystem;
CoordinateSystem3d Cs = ucs.CoordinateSystem3d;
Plane pn = new Plane(Point3d.Origin, Cs.Zaxis);
Vector3d normal = Cs.Zaxis;
//First point
PromptPointResult Pres = ed.GetPoint("\nPick the first point:");
if (Pres.Status != PromptStatus.OK) return;
Point3d U1 = Pres.Value;
//Second point
PromptPointOptions PPO = new PromptPointOptions
("\nPick the second point:");
PPO.UseBasePoint = true;
PPO.BasePoint = U1;
Pres = ed.GetPoint(PPO);
if (Pres.Status != PromptStatus.OK) return;
Point3d U2 = Pres.Value;
if (U1.Z != U2.Z) U2 = new Point3d(U2.X, U2.Y, U1.Z);
//Add pline
Polyline oPline = new Polyline(7);
oPline.Normal = Cs.Zaxis;
oPline.Elevation = -new Plane(Cs.Origin, Cs.Zaxis).Coefficients.D;
if (U1.Z != 0) oPline.Elevation = oPline.Elevation + U1.Z;
Point2d P1 = U1.TransformBy(ucs).Convert2d(pn);
Point2d P2 = U2.TransformBy(ucs).Convert2d(pn);
oPline.AddVertexAt(0, P1, 0, 0, 0);
oPline.AddVertexAt(1, P2, 0, 0, 0);
Vector2d v = (P2 - P1).GetNormal().RotateBy(Math.PI * 0.5);
using (Transaction tr = doc.Database.TransactionManager.StartTransaction())
{
BlockTableRecord Cspace = tr.GetObject(db.CurrentSpaceId, OpenMode.ForWrite) as BlockTableRecord;
Cspace.AppendEntity(oPline);
tr.AddNewlyCreatedDBObject(oPline, true);
tr.Commit();
}
Double dOffset = 51;
//Always on the bottom
int iOffset = 1;
if (P2.X < P1.X) iOffset = -1;
v = v * iOffset * -dOffset;
using (Transaction tr = doc.Database.TransactionManager.StartTransaction())
{
oPline = tr.GetObject(oPline.Id, OpenMode.ForWrite) as Polyline;
oPline.AddVertexAt(2, P2.Add(v), 0, 0, 0);
oPline.AddVertexAt(3, P1.Add(v), 0, 0, 0);
oPline.Closed = true;
tr.Commit();
}
} //End MultiLine
