Returns a String with the name of the .prj or .lib file containing the object. In E3 Studio, this property returns the project's or library's full path (c:\folder\folder\volume.prj). At run time, the objects executing in E3 Viewer always return an empty String. However, objects executing in a server return the project's or library's relative path, according to the way it is stored in the Domain (volume.prj). This value is determined only at request, thus it is not recommended to create Links to this property. This is a read-only property.