A method is developed of incorporating the effects of change of geometry in the analysis of rigidly jointed plane frames when using the displacement method. Where members are split into a moderate number of submembers the effects of change of geometry can be sufficiently represented by means of a nonlinear displacement transformation alone. Accurate results can be obtained with few submembers if the approximate nonlinear behavior of the submembers are taken into account. The method remains valid for cases of extreme deformation as long as the exact mathematical form of the displacement transformation is used.