The following values are allowed
- Default -> The settings from the rulebook will be applied to the (default) duct
- Force inner ducts -> Regardless of the settings in the rule set, inner pipes are always created (Comsof Fiber Designer only)
- Force direct cables -> cables are placed directly in the stock pipe (currently not supported)
The project validation checks whether the attribute is supported by the selected optimizer and the installed version. It also checks that the "Default" duct in the "Already exists" attribute is set to "Yes". For "Default" ducts with the attribute "Already exists" = NO, only the value "Default" is accepted.