Integrating into the design process the needs of those involved in the product life-cycle

Numerous design methods exist but models and tools used by these design methods do not realize a complete coherence between customers' needs, professionals' needs and solutions that can be found. So, in this paper we will examine the functional analysis method that was specifically developed to allow needs to be taken into account during the design stages. We will present our interpretation of that method and how it could serve to assure this coherence. We will put forward a design activities model, integrating into the design process the needs of those involved in the product life-cycle. Our observations relative to the implementation of the functional analysis method will lead us to supplement this initial model and suggest tools to help designers.