[en] The method of a choice of self-similar variables for the description of multi-dimension wave collapse (WC) evolution is offered. It is based on the requirement that self-similar variables should provide preservation of an average square of radius of a wave package. Proposed self-similar substitutions do not break convertibility of the initial equation and allow us to present an average square of width of a wave package in a universal kind. In offered self-similar variables a spherical-symmetric stretched in the one of directions WC is investigated