Intersectwith方法得出错误结果

Sub LevelFromTria2()
    Dim objPLine As AcadLWPolyline
    Dim objTria As Acad3DFace
    Dim varCoords As Variant  '
    Dim objBlock As AcadBlock
    Dim lngCount As Long
    Dim objTriaSides As AcadLWPolyline
    Dim varIntPoints As Variant
    Dim dblTriaSidesCoords(0 To 5) As Double
    Dim varPnt As Variant
    
    
    On Error Resume Next '* Do so that if layer exists no error
    ThisDrawing.Layers.Add ("Temp Triangles")
    On Error GoTo 0
    ThisDrawing.Utility.GetEntity objPLine, varPnt, "Select polyline: "
    Set objBlock = ThisDrawing.Blocks("draw tria exploded")
    
    '* Go through all the items in the xref
    For lngCount = 0 To objBlock.Count - 1
    
        '* See if the item is a 3d face
        If objBlock.Item(lngCount).ObjectName = "AcDbFace" Then
            '* If it is get the face element
            Set objTria = objBlock.Item(lngCount)
            '* See if the face intersects with the polyline
            varIntPoints = objTria.IntersectWith(objPLine, acExtendNone)
            
            '* If it does, draw the triangle - TEMP MEASURE TO SEE IF IT IS FINDING THE RIGHT TRIANGLES
            If VarType(varIntPoints)  vbEmpty Then
                '* Get co-ords of the 3d face
                varCoords = objTria.Coordinates
                '* Set up 2d coords for the triangle edge
                dblTriaSidesCoords(0) = varCoords(0)
                dblTriaSidesCoords(1) = varCoords(1)
                dblTriaSidesCoords(2) = varCoords(3)
                dblTriaSidesCoords(3) = varCoords(4)
                dblTriaSidesCoords(4) = varCoords(6)
                dblTriaSidesCoords(5) = varCoords(7)
                '* Add a LW polyline to show the triangle which intersects with the polyline
                Set objTriaSides = ThisDrawing.ModelSpace.AddLightWeightPolyline(dblTriaSidesCoords)
                objTriaSides.Closed = True
                objTriaSides.Layer = "Temp Triangles"
                objTriaSides.color = acMagenta
                objTriaSides.Update
            End If
            
        End If
    
    Next lngCount
                        
End Sub