When you right-click on a file, using Windows Explorer, and pick "Properties...", to bring up the File Properties dialog, you can add summary information to a file by clicking on the Summary tab and entering the appropriate information. For example:

Is there a way to bring up this dialog when saving Rhino files?
Rhino does not have this capability. But, it is possible to create a script, using RhinoScript that will do this.
The following sample script will save the Rhino file by scripting Rhino's Save command. If the command was successful in saving the file, script will then display the File Properties dialog and display the summary information for that file.
Sub SuperSaver()
Rhino.Command "_Save"
If (0 = Rhino.LastCommandResult()) Then
Dim objShell, objFolder, objFolderItem, objInfo
Set objShell = CreateObject("Shell.Application")
Set objFolder = objShell.NameSpace(Rhino.DocumentPath)
If (Not objFolder Is Nothing) Then
Set objFolderItem = objFolder.ParseName(Rhino.DocumentName)
If (Not objFolderItem Is Nothing) Then
Call objFolderItem.InvokeVerbEx("properties", "summary")
End If
Set objFolderItem = Nothing
End If
Set objFolder = Nothing
Set objShell = Nothing
End If
End Sub
_-NoEcho _-RunScript (
Rhino.Command "_Save"
If (0 = Rhino.LastCommandResult()) Then
Set objShell = CreateObject("Shell.Application")
Set objFolder = objShell.NameSpace(Rhino.DocumentPath)
If (Not objFolder Is Nothing) Then
Set objFolderItem = objFolder.ParseName(Rhino.DocumentName)
If (Not objFolderItem Is Nothing) Then
Call objFolderItem.InvokeVerbEx("properties", "summary")
End If
Set objFolderItem = Nothing
End If
Set objFolder = Nothing
Set objShell = Nothing
End If
)