VB's getPointAtDist?

Is there a VB analog to LISP's getPointAtDist function?
My goal is actualy to get a midpoint of a polyline.

 

Yes, sortof, using Frank Oquendo's VLAX and Curve classes. See a request by
me for these from a month or two ago. I don't have them on this machine or
I'd post them again.

Jeff

 

Or simply find the polyline's midst segment, then find the mid point of that
segment. Pure VBA.

Regards,
Maksim Sestic

 

And if a polyline has an even number of segments?

Besides, what makes you think these classes are not pure VBA?

 

What if the pline had a bunch of short segs on one side and long one(s) on
other side(of center)?

 

Also, that would require that each segment be equal length, e.g. a 3 segment pl with lengths of 10,10,1 units. The midpoint would not be on the *middle* of the second segment, but weighted toward the first segment.

--
----
Ed
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And if a polyline has an even number of segments?

Besides, what makes you think these classes are not pure VBA?

 

Allright, allright, my mistake - here's the coded answer (more or less): It
solves LWPlines with line segments only - no arcs included. Also no error
trapping of any kind. Pass the function the LWPline length (search the code
down the NG) divided by 2 and the LWPline itself.

'===========================================================================
====
' Stationery point along LWPolyline
' Input: polyline length/2 and polyline itself
' Result: forced 2D point (three element array of doubles)
'===========================================================================
====
Function StacionazaTacka(valStacionaza As Double, obj As AcadLWPolyline) As
Variant
Dim Coords As Variant
Dim UBnd As Long
Dim PntA(0 To 2) As Double
Dim PntB(0 To 2) As Double
Dim PntX As Variant
Dim RunDist As Double
Dim DistAB As Double
Dim i as Long

RunDist = 0
DistAB = 0
Coords = obj.Coordinates
UBnd = UBound(Coords)

i = 0
Do While True
PntA(0) = Coords(i): PntA(1) = Coords(i + 1): PntA(2) = 0
PntB(0) = Coords(i + 2): PntB(1) = Coords(i + 3): PntB(2) = 0
DistAB = XYDistance(PntA, PntB)
PrevDist = RunDist
RunDist = RunDist + DistAB
If RunDist >= valStacionaza Then
ugao = ThisDrawing.Utility.AngleFromXAxis(PntA, PntB)
Razlika = DistAB - (RunDist - valStacionaza)
PntX = ThisDrawing.Utility.PolarPoint(PntA, ugao, Razlika)
StacionazaTacka = Array(PntX(0), PntX(1), 0#)
Exit Do
End If
If i + 2 > UBnd Then
StacionazaTacka = Array(0#, 0#, 0#)
Exit Do
Else
i = i + 2
End If
Loop
End Function