Access a Curves Control Points

Replies to This Discussion

Permalink Reply by Damien Alomar on December 4, 2009 at 7:37am

You'll have to convert the OnCurve to an OnNurbsCurve, and then get the control vertices from that. Your special case of a polyline doesn't really matter, so this should work for getting the CVs from any curve. The example below assumes two inputs, crv and i, which are typed as an OnCurve and Integer, respectively

Dim nCrv As New OnNurbsCurve
crv.NurbsCurve(nCrv)

If i < nCrv.CVCount Then
Dim cvPt As New On3dPoint()
nCrv.GetCV(i, cvPt)
A = cvPt
Else
A = "Beyond Last Index"
End If

Permalink Reply by Suryansh Chandra on December 5, 2009 at 10:26am

Damien's code would get you a specific CV by index.. you could use the same code and put it in a FOR loop to get all CVs..

If you are dealing with a polyline, you dont even need to script.. just use a 'decompose' (I'm not sure about the name.. it could be called Explode or shatter) component which will give you lines, and then use Curve.EndPoints to get all the start pts or end pts of the lines..

Permalink Reply by matthias rümmele on December 5, 2009 at 10:54am

Thank you guys!

I'm glad to have Damiens answer, even if i don't need it for that special case of a polyline. But i can remember a situation about a month ago where i have been looking for a curves control points and couldn't find it in the SDK. Can't remember the workaround i did then, but in the future i will be able to get them through scripting.

Permalink Reply by Dave Johnson on March 6, 2012 at 1:31pm

Even quicker is to use the Discontinuities component, it will give you polyline vertices directly.

Permalink Reply by Dirk Anderson on December 8, 2009 at 4:17am

here's a specific VB script that extracts all points of a polyLine:

Private Sub RunScript(ByVal x As OnCurve, ByRef A As Object)
Dim ptList As New List( Of On3dPoint)
Dim pLine As New OnPolyline

If x.IsPolyline(pLine) Then
For i As Int32 = 0 To pLine.Count() - 1
ptList.Add(pLine(i))
Next
End If

A = ptList

End Sub

Permalink Reply by dumo on December 8, 2009 at 12:57pm

hello

does anyone know how to create polylines from on3points in a vb node?
without having to write a function?

thank you

Permalink Reply by Suryansh Chandra on December 9, 2009 at 5:36am

Dim mycrv as new OnPolylineCurve(CVarray)

Thats it!