A new approach to power spectrum calculation of structures characterized by a spatial distribution of localized physical events, which has the advantage of being flexible enough to describe practically any type of local order and of giving the results in a very compact and general form, is given. Starting from a completely ordered three‐dimensional structure, with the elementary events arranged according to an arbitrary crystallographic order, the disorder is introduced by displacing the elementary events from their lattice position. The displacements are described from a probabilistic point of view by means of three general distribution functions which can be related to the interaction forces acting between nearest neighbour events and using a convolution technique for describing self‐consistently the whole structure, whose statistical properties remain translationally invariant. A simple analytic expression is obtained where different degrees of short‐range order with any local crystallographic configuration can be introduced and characterized.