Difference between in GetOpenDocumentByName and OpenDoc6

GetOpenDocumentByName ------------- Not open File,Solidowrks file established and communications.

Function SetSwNamePart(FileName)
  Dim SwApp As Object
  Dim SelMgr As Object, boolstatus As Boolean
  Dim longstatus As Long, longwarnings As Long

  Set SwApp = GetObject(, "sldworks.application")
  'Debug.Print IsNull(swApp)
  Set SetSwNamePart = SwApp.GetOpenDocumentByName(FileName)
  'swApp.Visible = True
End Function

-------

OpenDoc6-----Must file open, and establish communication with solidowrks

Function SwOpenFile(SwApp, OpenFile)
    'Debug.Print OpenFile
'    SwApp.Visible = True
    Dim SwPart             As Object
    Dim nDocType            As Long
    Dim nErrors             As Long
    Dim nWarnings           As Long
    Dim swOpenDocOptions_Silent
    swOpenDocOptions_Silent = 1
    ' Determine type of SolidWorks file based on file extension

    If InStr(LCase(OpenFile), "sldprt") > 0 Then
        nDocType = 1 'swDocPART
    ElseIf InStr(LCase(OpenFile), "sldasm") > 0 Then
        nDocType = 2 'swDocASSEMBLY
    ElseIf InStr(LCase(OpenFile), "slddrw") > 0 Then
        nDocType = 3 'swDocDRAWING
    Else
        ' Probably not a SolidWorks file...
        nDocType = swDocNONE
        '...so the file cannot be opened
        Exit Function
    End If
    ''
    'Set SwPart = SwApp.OpenDoc6(OpenFile, nDocType, _
                    swOpenDocOptions_Silent, "", nErrors, nWarnings)
    'Set SwPart = SwApp.OpenDoc6(OpenFile, 1, 1, "", nErrors, nWarnings)
   
    Set SwOpenFile = SwPart
   'Debug.Print SwPart.GetPathName
End Function

SolidworksApi macros