Planning multi-variant products in the early stage of the design process is still a challenge. In the present paper, a specification technique is introduced in order to define multi-variant products using degrees of freedom of shape attributes (in the following shape-DoFs) within the product structure. Our goal is to plan variety actively at the beginning of product development and not to describe variety by change of parameter values of the product's components as introduced in variant trees. Shape-DoFs are classified in the fields of shape attributes (dimension, position, shape as well as their combinations) on the one hand and mandatory or optional components on the other hand. Set up on this taxonomy graphical symbols are introduced to be used in product modeling. As application example, a welded pipe rack based upon the assembly structure modeling the product structure in this way is visualized in the first step. The second step is to translate the shape-DoFs into design parameters and identify relationships between them. The result is a parameter plan, as well as a configuration concept. Both can be seen as basis for CAD-modeling the product as design template which is the third step. In case of our example, Autodesk Inventor (without the ETO-Environment) is used to create the CAD-data. Discussing the effects of the proposed method, it will be shown that different shape-DoFs may cause various impacts in the whole product development process. Regarding these effects, scenarios can be performed in order to identify the cost and resource optimal variation possibilities of the product. In addition, it will be shown that different kinds of modularity according to PINE (e.g. cut-to-fit-modularity) can be predefined in the product model by using shape-DoFs.