LineSegment.IntersectWithSurface method failing - showing 'fake' intersection

[basnederveen]

Hi

I'm trying to find the intersection of a line with a cylinder, but it is giving me fake results. Included is a screenshot  of the line and surface I am using. Somehow the method intersectwithsurface is returning 1 intersection here.

I've just created an assembly with 2 parts, both having 1 work point. Between these points I create 1 line. I've added the transientobjects to see the linesegment and the cylinder. 

How come this returns an intersection, when it does not? Also the intersection point is not even remotely close to the cylinder..?

Code for testing:

Sub TestRopes()

Dim asm As AssemblyDocument
Set asm = ThisApplication.ActiveDocument

Dim occ1 As ComponentOccurrence, occ2 As ComponentOccurrence
Set occ1 = asm.ComponentDefinition.Occurrences.Item(2)
Set occ2 = asm.ComponentDefinition.Occurrences.Item(3)

Dim wp1 As WorkPoint, wp2 As WorkPoint
Dim wpp1 As WorkPoint, wpp2 As WorkPoint
Set wp1 = occ1.Definition.WorkPoints.Item(2)
Set wp2 = occ2.Definition.WorkPoints.Item(2)

Call occ1.CreateGeometryProxy(wp1, wpp1)
Call occ2.CreateGeometryProxy(wp2, wpp2)

Call DisplayLine(wpp1.Point, wpp2.Point)
End Sub

Public Sub DisplayLine(MinPoint As Point, maxpoint As Point)

    ' Set the active document
    Dim oDoc As Document
    Set oDoc = ThisApplication.ActiveDocument

    ' Set a reference to component definition of the active document.
    ' This assumes that a part or assembly document is active.
    Dim oCompDef As ComponentDefinition
    Set oCompDef = ThisApplication.ActiveDocument.ComponentDefinition
    
    ' Check to see if the test graphics data object already exists.
    ' If it does clean up by removing all associated of the client graphics
    ' from the document.  If it doesn't create it.
    On Error Resume Next
    Dim oGraphicsData As GraphicsDataSets
    Set oGraphicsData = oDoc.GraphicsDataSetsCollection.Item("SampleGraphicsID")
    If Err.Number = 0 Then
    
        On Error GoTo 0
        ' An existing client graphics object was successfully obtained so clean up.
        oGraphicsData.Delete
        oCompDef.ClientGraphicsCollection.Item("SampleGraphicsID").Delete
    
        ' update the display to see the results.
        ThisApplication.ActiveView.Update
        Call DisplayLine(MinPoint, maxpoint)
    Else
    
        Err.Clear
        On Error GoTo 0
        
        ' Set a reference to the transient geometry object for user later.
        Dim oTransGeom As TransientGeometry
        Set oTransGeom = ThisApplication.TransientGeometry
    
        ' Create a graphics data set object.  This object contains all of the
        ' information used to define the graphics.
        Dim oDataSets As GraphicsDataSets
        Set oDataSets = oDoc.GraphicsDataSetsCollection.Add("SampleGraphicsID")
        
        ' Create a coordinate set.
        Dim oCoordSet As GraphicsCoordinateSet
        Set oCoordSet = oDataSets.CreateCoordinateSet(1)

        ' Create an array that contains coordinates that define a set
        ' of outwardly spiraling points.
        Dim oPointCoords(1 To 6) As Double
        oPointCoords(1) = MinPoint.X
        oPointCoords(2) = MinPoint.y
        oPointCoords(3) = MinPoint.z
        oPointCoords(4) = maxpoint.X
        oPointCoords(5) = maxpoint.y
        oPointCoords(6) = maxpoint.z
        
        ' Assign the points into the coordinate set.
        Call oCoordSet.PutCoordinates(oPointCoords)
        
        ' Create the ClientGraphics object.
        Dim oClientGraphics As ClientGraphics
        Set oClientGraphics = oCompDef.ClientGraphicsCollection.Add("SampleGraphicsID")
        
        ' Create a new graphics node within the client graphics objects.
        Dim oLineNode As GraphicsNode
        Set oLineNode = oClientGraphics.AddNode(1)
        
        ' Create a LineGraphics object within the node.
        Dim oLineSet As LineGraphics
        Set oLineSet = oLineNode.AddLineGraphics
        
        ' Assign the coordinate set to the line graphics.
        oLineSet.CoordinateSet = oCoordSet
        
        ' Assign a color to the node using an existing appearance asset.
        Dim oAppearance As Asset
        Set oAppearance = oDoc.AppearanceAssets(1)

        oLineNode.Appearance = oAppearance
        
        Dim oColorSet As GraphicsColorSet
        Set oColorSet = oDataSets.CreateColorSet(1)
        
        ' Add a single color to the set that is red.
        Call oColorSet.Add(1, 255, 0, 0)
        oLineSet.ColorSet = oColorSet
        
        ' Create a new graphics node within the client graphics objects
        Dim oSurfacesNode As GraphicsNode
        Set oSurfacesNode = oClientGraphics.AddNode(1)
        
        Dim oTransientBRep As TransientBRep
        Set oTransientBRep = ThisApplication.TransientBRep
        
        ' Create a point representing the center of the bottom of
        ' the cone
        Dim oBottom As Point
        Set oBottom = _
        ThisApplication.TransientGeometry.CreatePoint(0, -1050, 330)
        
        ' Create a point representing the tip of the cone
        Dim oTop As Point
        Set oTop = _
        ThisApplication.TransientGeometry.CreatePoint(13000, -1050, 330)
        
        ' Create a transient cylinder body
        Dim oCylBody As SurfaceBody
        Set oCylBody = oTransientBRep.CreateSolidCylinderCone( _
        oBottom, oTop, 330, 330, 330)
        
        ' Create client graphics based on the transient body
        Dim oSurfaceGraphics As SurfaceGraphics
        Set oSurfaceGraphics = oSurfacesNode.AddSurfaceGraphics(oCylBody)
         
        ' Update the view to see the resulting line.
        ThisApplication.ActiveView.Update
        
        ' Create reference to transient geo
    Dim oTG As TransientGeometry
    Set oTG = ThisApplication.TransientGeometry
 
    ' Create a linesegment
    Dim l As LineSegment
    Set l = oTG.CreateLineSegment(MinPoint, maxpoint)
            
    ' Create a point, unitvector and then a cylinder 
    Dim p As Point
    Set p = oTG.CreatePoint(0, -1050, 330)

    Dim uv As UnitVector
    Set uv = oTG.CreateUnitVector(1, 0, 0)
    
    Dim cyl As Cylinder
    Set cyl = oTG.createCylinder(p, uv, 330)
    
    Dim cylClashes As ObjectsEnumerator
    Set cylClashes = l.IntersectWithSurface(cyl)
    Stop
        
    End If
End Sub

So a cylinder with origin (0,-1050,330) would mean its rangebox min/max is respectively (0,-1380,0) (x,-720,660), x being infinite.

How come the intersectwithsurface method returns an intersection with coordinate (1375, -840, 3667) ??

Am I doing something wrong?