topic Re: convert Arc to polyline in .NET Forum

convert Arc to polyline

youssefGC — Sat, 11 Feb 2023 21:28:06 GMT

Hi everyone,

There is a way to convert arc segment to polyline object ?

Re: convert Arc to polyline

MGO-Norsyn — Sat, 11 Feb 2023 21:42:50 GMT

Yes, create new Polyline, add the two arc ends as vertices, calculate bulge and set it for the polyline segment.

Re: convert Arc to polyline

MGO-Norsyn — Sat, 11 Feb 2023 21:47:15 GMT

double r = arc.Radius; double u = arcStartPoint.GetDistanceTo(arcEndPoint); double b = (2 * (r - Math.Sqrt(r.Pow(2) - u.Pow(2) / 4))) / u;

Re: convert Arc to polyline

_gile — Sun, 12 Feb 2023 08:08:45 GMT

Hi,

Here's an example (refactored code):

var pline = new Polyline(); double angle = arc.EndAngle - arc.StartAngle; if (angle < 0.0) angle += 2.0 * Math.PI; double bulge = Math.Tan(angle / 4.0); var plane = new Plane(Point3d.Origin, arc.Normal); pline.AddVertexAt(0, arc.StartPoint.Convert2d(plane), bulge, 0.0, 0.0); pline.AddVertexAt(1, arc.EndPoint.Convert2d(plane), 0.0, 0.0, 0.0); pline.Normal = arc.Normal;

Re: convert Arc to polyline

youssefGC — Sat, 11 Feb 2023 23:10:23 GMT

Thank you _gile, I'm still learning from your tricks.

Re: convert Arc to polyline

youssefGC — Sat, 11 Feb 2023 23:14:37 GMT

Thank you, but it doesn't march when I put an arc with an angle greater than 180 degrees