A method for extracting material information on sheet metal parts from an assembly model is proposed. In order to estimate the cost and order the required sheet metals, their outline profiles, thicknesses, quantities, and etc. are needed. The proposed method consists of two steps: First, sheet metal parts are selected through a feature recognition process from an assembly model. Then, some geometric information for the parts is calculated. In the later step a flattening process of bent parts is included. The method is implemented on a commercial CAD/CAM system Unigraphics with API routines and applied to steam turbine generators and large scale boilers.