topic Re: pick polyline and get nearest vertex coordinate in .NET Forum

pick polyline and get nearest vertex coordinate

wang890 — Mon, 28 Jun 2010 22:37:59 GMT

i am making a command in vb.net which user pick a polyline and the program get it's layer name and place a text that lines up with the polyline.

i can pick the polyline and get layer and put text no problem. but how do i go from GetSelection() to getting a proximity coordinate and get the vertex and previous (or next) vertex and get an angle and apply to the text?

see attached picture for what i am trying to do.

Re: pick polyline and get nearest vertex coordinate

Anonymous — Mon, 28 Jun 2010 23:39:50 GMT

Set the PromptSelectionOptions.PrepareOptionalDetails argument to true, and

then if the user picks the polyline, the object in the selection set will be a

PickPointSelectedObject, and you can examine it to find out where it was

picked. You can use Curve.GetParameterAtPoint() to get the index of the

vertex/segment that was picked based on the pick point.

Re: pick polyline and get nearest vertex coordinate

wang890 — Tue, 29 Jun 2010 00:46:59 GMT

hi Tony

i found out how to get the point user selected, but can you tell me how the curve.GetParameterAtPoint works?

thanks.

Re: pick polyline and get nearest vertex coordinate

wang890 — Tue, 29 Jun 2010 01:41:34 GMT

i got the point like this:

Dim poly As Polyline = TryCast(tr.GetObject(prResult.Value(0).ObjectId, OpenMode.ForRead), Polyline)

Dim ppso As PickPointSelectedObject = DirectCast(prResult.Value(0), PickPointSelectedObject)

Dim p3d As Point3d = poly.GetClosestPointTo(ppso.PickPoint.PointOnLine, False)

but it's not the point i want. i want the closest vertex. so i can get it's index and get the next one and calculated an angle.

right now it's giving the picked point on the polyline. it's what some people want not for me this time.

Re: pick polyline and get nearest vertex coordinate

Anonymous — Tue, 29 Jun 2010 08:49:35 GMT

The GraphicsSystemMarker property of the PickPointSelectedObject

gives you the index of the selected polyline segment.

Re: pick polyline and get nearest vertex coordinate

wang890 — Tue, 29 Jun 2010 16:47:09 GMT

ha, you are genius. there is no way i can figure this out on my own.

thank you so much!