Creating polyLine Arc using C# for AutoCAD 2014
Hi,
There is a lack of information to respond to your request.
What exactly are the input data?
AutoCAD manages the arc polyline segments with the bulge concept. The bulge of a segment is equal to the tangent of the quarter of the angle of the arc (IOW, the arc sagitta divided by half of the chord).
Here is an example that reproduces the behavior of the _PLINE native command by computing the bulge so that the arc is tangent to the previous segment.
[CommandMethod("Test")]
public void Test()
{
Document doc = AcAp.DocumentManager.MdiActiveDocument;
Database db = doc.Database;
Editor ed = doc.Editor;
// prompt for first point
var options = new PromptPointOptions("\nFirst point: ");
var result = ed.GetPoint(options);
if (result.Status != PromptStatus.OK)
return;
var pt1 = result.Value;
// prompt for second point
options.Message = "\nSecond point: ";
options.BasePoint = pt1;
options.UseBasePoint = true;
result = ed.GetPoint(options);
if (result.Status != PromptStatus.OK)
return;
var pt2 = result.Value;
// prompt for third point
options.Message = "\nThird point: ";
options.BasePoint = pt2;
result = ed.GetPoint(options);
if (result.Status != PromptStatus.OK)
return;
var pt3 = result.Value;
// convert points to 2d points
var plane = new Plane(Point3d.Origin, Vector3d.ZAxis);
var p1 = pt1.Convert2d(plane);
var p2 = pt2.Convert2d(plane);
var p3 = pt3.Convert2d(plane);
// compute the bulge of the second segment
var angle1 = p1.GetVectorTo(p2).Angle;
var angle2 = p2.GetVectorTo(p3).Angle;
var bulge = Math.Tan((angle2 - angle1) / 2.0);
// add the polyline to the current space
using (Transaction tr = db.TransactionManager.StartTransaction())
{
var curSpace = (BlockTableRecord)tr.GetObject(db.CurrentSpaceId, OpenMode.ForWrite);
using (var pline = new Polyline())
{
pline.AddVertexAt(0, p1, 0.0, 0.0, 0.0);
pline.AddVertexAt(1, p2, bulge, 0.0, 0.0);
pline.AddVertexAt(2, p3, 0.0, 0.0, 0.0);
pline.TransformBy(ed.CurrentUserCoordinateSystem);
curSpace.AppendEntity(pline);
tr.AddNewlyCreatedDBObject(pline, true);
}
tr.Commit();
}
}
Can you give more help Please, to create PolyLine from First point to Second point with fixed length (Current LTSCALE). Actually, After getting the first point the Polyline Automatically drawn a polyline as per current LTSCALE value (Current LTSCALE = Auto drawn polyline) followed the second point angle now the Arc will be drawn after getting the second vertex..
Sorry, I cannot understand what you want to do.
Could you provide a clearer explaination, maybe with some picture, and try to think at all necessary inputs to create the polyline (a length from a point is not enough to define another point).
You can also prompt the user for the first segment angle instead of a second point and compute the second point according to the angle and the LTSCALE value:
[CommandMethod("Test")]
public void Test()
{
Document doc = AcAp.DocumentManager.MdiActiveDocument;
Database db = doc.Database;
Editor ed = doc.Editor;
// prompt for first point
var options = new PromptPointOptions("\nSpecify the first point: ");
var result = ed.GetPoint(options);
if (result.Status != PromptStatus.OK)
return;
var pt1 = result.Value;
// prompt for the first segment angle
var angleOptions = new PromptAngleOptions("\nSpecify the first segment angle: ");
angleOptions.BasePoint = pt1;
angleOptions.UseBasePoint = true;
var angleResult = ed.GetAngle(angleOptions);
if (angleResult.Status != PromptStatus.OK)
return;
// compute the second point
var pt2 = new Point3d(
pt1.X + Math.Cos(angleResult.Value) * db.Ltscale,
pt1.Y + Math.Sin(angleResult.Value) * db.Ltscale,
pt1.Z);
// prompt for third point
options.Message = "\nSpecify the arc end point: ";
options.BasePoint = pt2;
options.UseBasePoint = true;
result = ed.GetPoint(options);
if (result.Status != PromptStatus.OK)
return;
var pt3 = result.Value;
// convert points to 2d points
var plane = new Plane();
var p1 = pt1.Convert2d(plane);
var p2 = pt2.Convert2d(plane);
var p3 = pt3.Convert2d(plane);
// compute the bulge of the second segment
var angle1 = p1.GetVectorTo(p2).Angle;
var angle2 = p2.GetVectorTo(p3).Angle;
var bulge = Math.Tan((angle2 - angle1) / 2.0);
// add the polyline to the current space
using (Transaction tr = db.TransactionManager.StartTransaction())
{
var curSpace = (BlockTableRecord)tr.GetObject(db.CurrentSpaceId, OpenMode.ForWrite);
using (var pline = new Polyline())
{
pline.AddVertexAt(0, p1, 0.0, 0.0, 0.0);
pline.AddVertexAt(1, p2, bulge, 0.0, 0.0);
pline.AddVertexAt(2, p3, 0.0, 0.0, 0.0);
pline.TransformBy(ed.CurrentUserCoordinateSystem);
curSpace.AppendEntity(pline);
tr.AddNewlyCreatedDBObject(pline, true);
}
tr.Commit();
}
}
Hi Gilles,
We have an option in autocad, when we drawing Polyline with ARc option. Here is my need is to draw multiline with arc option, when user given command to draw a acr in a multiline.
Screen shots provided below. Request you to Please provide the code to accomplish the requirement.
Note : I want to built it in Autocad 2016
Regards
Alex Andrews.
Hi Gilles,
Could you please help me to draw polyline with Arc options in AutoCAD using C#.net. And the same Polyline with the combination of Arc to placed with some Offset distance.
The Screen shot which I shown below.
@Anonymous
In view of the screenshots you send, it seems that you are ignoring some AutoCAD basics (like the _OFFSET command).
In my opinion, it is not possible to pretend to customize AutoCAD with code without mastering these databases.
You should start by learning how to use the _OFFSET command, then you can better understand how the GetOffsetCurves() method works (if the offset distance is positive the curve is offseted to the right, if it is negative, to the left).
