In the multimedia documents authoring systems the management of spatial and temporal inter-objects relations is the most delicate task. Spatial relations management refers to the appropriate means to express relations between the document objects and guarantee their consistency. Usually it is represented by spatial model which performances depend on its expressivity degree, on its positioning precision and on the ability to express a desired overlap. One of the most important factor that affects performnaces is the distance associated to the relations. To enhance the expressivity and precision degrees and to allow the specification of desired overlap, we introduce, in this paper, the flexible distance concept