This work proposes a representation scheme that uses CAD as a design tool for generating two-dimensional decorative patterns. The proposed scheme is hierarchical and represented as a tree with nodes corresponding to different shapes of pattern. In this work, decorative patterns are viewed as a set of shapes created at three hierarchical levels which are labeled as: Primitive, Motif, and Compound-motif. This CAD paradigm helps the designers/artists to manipulate a set of fundamental shapes (primitive, motif and compound-motif) by transformation rules and to arrange them into some definite order for generating a decorative pattern.