This work deals with the automated creation of a design model for butterfly valves. The method of parameterization was chosen to solve the complex task. The used construction program communicates with a central control file which contains the analytical formulas of the underlying design process. The state of the art for butterfly valves is presented in the first part of the work. The structural requirements for these safety-critical machine elements are explained and the usual valve design concepts discussed. In the second part, the process of parameterization is examined and its internal and external interfaces for data processing are explained. In the third part, the invoked mechanical engineering rules are discussed on the basis of characteristic components to highlight the features of the implemented parameterization method. Finally, the concluding part compares the results of the automated model design with existing plants. The work facilitated a much faster model deduction in the project phase of butterfly valves. The automated design process can also support the entire pre-dimensioning. Exemplarily, a butterfly assembly consists of about 127 components, which are grouped into 11 subassemblies, and is controlled by approximately 1500 geometry-generating parameters via about 300 independent input values. The developed design tool can represent sixteen different main variants and thus covers already most of the different customer requirements. Due to the high accuracy in the determination of component wall thicknesses, cost-effective loops between the design and calculation department were minimized during the design process. The entire construction process is shortened by 30 - 50% and meets the general demand for constructive lightweight construction due to high utilization rates. Offers for new equipment can also be derived more quickly, efficiently and accurately. Hence, the entrepreneurial risk of complex offers can be decisively reduced by invocation of this reliable pre-dimensioning tool.