topic Re : Polyline with Arc in .NET Forum

Polyline with Arc

ditran7577 — Fri, 23 Aug 2013 07:36:30 GMT

Hi everyone,

I'm having a problem when I create polyline with arc using vb.net. The arc is a quarter of ellipse. Please see picture below for detail.

Thanks any helps.

Re: Polyline with Arc

R.Gerritsen4967 — Fri, 23 Aug 2013 07:52:49 GMT

An ellipse is not an arc and cannot be joined to a polyline.

Maybe you can try to facet the ellipse. With this you turn the ellipse into a polyline that's almost (but not exactly!) following the same path as the ellipse.

Here's an excellent explanation, including some code...

http://through-the-interface.typepad.com/through_the_interface/2009/12/faceting-autocad-curves-using-net.htmlhttp://

Re: Polyline with Arc

ditran7577 — Fri, 23 Aug 2013 08:10:23 GMT

How about SPLINE! Can we create a spline like blue arc (in picture)?

Thanks,

Re : Polyline with Arc

_gile — Fri, 23 Aug 2013 11:38:19 GMT

Hi,

Have a look at the GeometryExtensions library, specialy the PolylineSegment and PolylineSegmentCollection classes.

There's an example on how to use them here.

Re : Polyline with Arc

ditran7577 — Sat, 24 Aug 2013 07:31:52 GMT

Thank for help. Are there any way to draw only a quarter of ellipse.

Re : Polyline with Arc

_gile — Sat, 24 Aug 2013 10:47:13 GMT

You can set the StartAngle and EndAngle properties of the Ellipse instance. Angles are measured in radians CCW from the MajorAxis vector.

Re : Polyline with Arc

ditran7577 — Wed, 28 Aug 2013 05:39:20 GMT

Thank Gilles. This is exactly what I’m looking for.