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Precipitation hardening is a widely used method for increasing the critical resolved shear stress (CRSS) of a material. Our simulations offer a flexible means to calculate the CRSS as a function of many parameters involved, e.g. the average precipitate size. For this, one or more dislocations are simulated while gliding through obstacle fields of arbitrary type or spatial arrangement. The elastic self-interaction is fully allowed for. Unlike analytical approaches and simulations known from literature, our method covers both shearing and circumventing of obstacles in a single model. To start with, the obstacles used in this contribution were chosen to be spheres with a constant obstacle stress inside; the distribution of the radii and the spatial arrangement suit the case of Ostwald-ripened particles. This corresponds to the case of the nickel base superalloy NIMONIC PE16 where a dislocation has to create an antiphase boundary in order to shear the long range ordered precipitates. Typical examples for dislocation arrangements are presented, and the results for various obstacle concentrations and mean radii are compared with published results.