Geometric modelling is an established approach for gathering detailed knowledge about the chronological sequence of process conditions and for determining technological values of machining processes such as milling, turning, grinding or additive manufacturing. Performance and accuracy essentially depend on the chosen workpiece model and its parametrization. Furthermore, several influences on the investigated machine tool system lead to errors, which must be modeled separately. This paper shows approaches to increase performance and accuracy of the simulation by choosing an appropriate combination of different geometric representations of the workpiece and by considering possible errors within the kinematic model. Examples for different applications in metal cutting are given.