Layout design plays an important role in the design and usability of many engineering products and systems. Because of the great complexity of most of industrial layout problems, the decision of the acceptable layout is a hard and critical task since the special layout can have a significant consequence on the global performances. Thus, in order to propose to the designer an optimal spatial arrangement in a reasonable time, this paper develops an interactive optimization strategy that is tested on the facilities layout problem of a shelter. This problem is innovative because it introduces the concept of space of accessibility.