You define a C# namespace using a package.
PowerDesigner models namespaces as standard packages with the Use Parent Namespace property deselected.
In the following example, class Architect is declared in package Design which is a sub-package of Factory. The namespace declaration is the following:
namespace Factory.Design
{
 public class Architect
 {
 }
}
        Classifiers defined directly at the model level fall into the C# global namespace.