Models based on the dispersed barrier hardening (DBH) approach are often used for interpreting experimental results and estimating the mechanical response of irradiated materials. However, weakly physically based approaches and phenomenological fitting to the experimental data do not allow accurate accounting for obstacle size and temperature effects. In this work, we developed a simple approach that combines early parametric continuum modeling with current atomic scale dislocation dynamics. This approach allows us to estimate size and temperature dependent values of obstacle strength parameters, using the available atomistic modeling data. Examples are presented for cases in two materials of practical significance. These are voids, helium bubbles, copper precipitates, and rigid obstacles (imitating oxide particles) in bcc iron and voids and rhenium-rich precipitates in tungsten. The implication of these results to the understanding of experimental observations is discussed.