Extend lines to intersection

[erhan.lale]

I have a drawing like on left side:

a closed rectangle as polyline and 4 lines. I want to strech all lines to poyline, like the drawing on the right side.

Is it possible?

[norman.yuan · Accepted solution]

for each line inside the rectangle polyline, you can call:

Dim insPoints As Variant

insPoints = OneOfTheLine.IntersectWith(TheRectanglePoly, acExtendThis)

This is supposed to return you back an array of Double numbers (6 elements), representing 2 points., then you can set the line's Start/End points to these 2 points, thus extends it.

[erhan.lale]

How can i select a line, which created by explode?

I send an example code:

Sub extend_lines()
' Create polyline
Dim plineObj As AcadLWPolyline
Dim points(0 To 7) As Double
points(0) = 1: points(1) = 1
points(2) = 1: points(3) = 3
points(4) = 3: points(5) = 3
points(6) = 5: points(7) = 1

Set plineObj = ThisDrawing.ModelSpace.AddLightWeightPolyline(points)
plineObj.Closed = True

'create border
Dim plineBorder As AcadPolyline
Dim pntArr(0 To 11) As Double
Dim borderMin As Variant
Dim borderMax As Variant
Dim borderOffset As Double
plineObj.GetBoundingBox borderMin, borderMax

borderOffset = 1
borderMin(0) = borderMin(0) - borderOffset
borderMin(1) = borderMin(1) - borderOffset
borderMax(0) = borderMax(0) + borderOffset
borderMax(1) = borderMax(1) + borderOffset

pntArr(0) = borderMin(0): pntArr(1) = borderMin(1): pntArr(2) = borderMin(2):
pntArr(3) = borderMax(0): pntArr(4) = borderMin(1): pntArr(5) = borderMin(2):
pntArr(6) = borderMax(0): pntArr(7) = borderMax(1): pntArr(8) = borderMax(2):
pntArr(9) = borderMin(0): pntArr(10) = borderMax(1): pntArr(11) = borderMax(2)

Set plineBorder = ThisDrawing.ModelSpace.AddPolyline(pntArr)
plineBorder.Closed = True
plineBorder.Layer = "0"

'mirror plineObj
If MsgBox("Mirror?", vbYesNo) = vbYes Then
Dim mirrorPoint1(2) As Double
Dim mirrorPoint2(2) As Double
mirrorPoint1(0) = (borderMin(0) + borderMax(0)) / 2: mirrorPoint1(1) = borderMax(1): mirrorPoint1(2) = 0
mirrorPoint2(0) = (borderMin(0) + borderMax(0)) / 2: mirrorPoint2(1) = 0: mirrorPoint2(2) = 0
Set plineMirrored = plineObj.mirror(mirrorPoint1, mirrorPoint2)
plineMirrored.Explode
plineObj.Erase

Else
plineObj.Explode
End If
'extend lines to plineBorder

'how can i select lines, which created with explode?
End Sub

[Ed__Jobe · Accepted solution]

The return value of the Explode method is an array of objects. From the help chm:

' Explode the polyline
    MsgBox "Explode the polyline?", , "Explode Example"
    Dim explodedObjects As Variant
    explodedObjects = plineObj.Explode
    
    ' Loop through the exploded objects
    Dim I As Integer
    For I = 0 To UBound(explodedObjects)
        explodedObjects(I).Update
        MsgBox "Exploded Object " & I & ": " & explodedObjects(I).ObjectName, , "Explode Example"
        explodedObjects(I).Color = acByLayer
        explodedObjects(I).Update
    Next

You can then iterate the array to access the entities. Keep in mind that the Explode method does not explode the original pline. I give you a copy. You will probably want to delete the original.

[erhan.lale]

Thank you, you are the best!