Features allow one to associate human knowledge and product geometry. The authors proposed, in earlier publications, a unified feature modeling scheme with the aim to maintain the integrity and consistency of a product model. Different application feature models within and across different product life-cycle stages are integrated, and especially, nongeometric relations (besides geometric ones) are handled. In this paper, as an improvement to the previous work, two types of associations are introduced: sharing and dependency. In the context of conceptual and detail design stages, these associations are described and the implementation is discussed in detail.