For a long time, the deposition mechanism of pyrocarbon (PyC) from the gas phase has been interpreted in terms of diverse models. Today, the so-called droplet or agglomerate model shows a high degree of reliability. It quantitatively describes the growth mechanism of agglomerates, initiated by chemical and physical processes, taking place in the gas phase. From this model, one can deduce the morphology of the originating agglomerates, i.e., their final size as well as their composition of different components, and can correlate these results to the physical properties of the resulting PyC material.