...
RealFlow's “Particle Mesh” provides three modes to create completely different results and looks. To get a better understanding of how these methods work, please read the introduction “Isotropic vs Anisotropic” in the particle mesh description. The first method is called “Metaballs”. Metaballs can be seen as spheres which can influence one another to create an organic-looking, smooth surface. Metaball-based fluid meshes often show thick borders and require a certain amount of filtering or correspondingly high particle counts to achieve a better quality.
...