Abstract: A method and an apparatus reduce the complexity of the design of product platforms, of the design of product lines and of variant management. A product is broken down into systems, which are subdivided into modules. In any given product, each module is realized by one concrete module variant out of a set of possible module variants, where unwanted combinations are avoided. Packaging is supported across one or more systems. Variant management manages the set of all variants as a whole. The introduced method and the apparatus holds the advantage, that products, which comprise common module variants and variable module variants, can be designed more efficiently.