A TopographyBuilder builds a Topography-Object step by step. After the Topography-Object is build it can no longer modified but the TopographyBuilder can be modified (there is no possibility to remove/set members). To solve this problem, use this TopographyBuilder but only in the topographycreator-package! Each build Topography is a new Object. The references of the members of two Topography-Object can be the same because they wont be cloned.