  We present an overview of the current status of our efforts to derive the
microturbulence and macroturbulence parameters (ximic and ximac) from the
CIFIST grid of CO5BOLD 3D model atmospheres as a function of the basic stellar
parameters Teff, log g, and [M/H]. The latest results for the Sun and Procyon
show that the derived microturbulence parameter depends significantly on the
numerical resolution of the underlying 3D simulation, confirming that
`low-resolution' models tend to underestimate the true value of ximic.
Extending the investigation to twelve further simulations with different Teff,
log g, and [M/H], we obtain a first impression of the predicted trend of ximic
over the Hertzsprung-Russell diagram: in agreement with empirical evidence,
microturbulence increases towards higher effective temperature and lower
gravity. The metallicity dependence of ximic must be interpreted with care,
since it also reflects the deviation between the 1D and 3D photospheric
temperature stratifications that increases systematically towards lower
metallicity.
