A method, system and apparatus for visualization of versions of a BOM. In accordance with an embodiment of the invention, at least two different versions of a BOM can be loaded into a versioning data processing system of a modeling tool executing in memory of a computer. The data from both versions of the BOM can be loaded into a single table in which each row of the table can include columns for a class name of a corresponding class specified by one of the versions of the BOM, a version of the corresponding class and at least one characteristic of the corresponding class such as a member name, type, date, argument, or other annotations such as vocabulary, comments, date. Subsequently, the single table can be visualized in at least two different treemaps for at least two different attributes of the versions of the BOM set forth in the single table.