SPH neighbour interactions

In this video, I show the links between interacting particles. Each particle may interact with other particles : these particles are called its neighbours. Since pressure force is symetrical, each particle is also the neighbour for every particles it is interacting with. For the lisibility purpose of this video, space resolution is really, really coarse, it starts with 50 pixels between particles, and it ends with 10 pixels between particles. Interaction radius is also coarse to avoid to many links : interaction radius is twice the aimed space between particles, so it starts à 100 pixels and ends at 20 pixels. In my high resolution simulation, I use a space resolution of 1 pixel. I always use an interaction radius of 3 x particle spacing. It allows great incompressibility, without showing too much space between particle clusters near the surface. With higher interaction radius, for example 4 x particle spacing, particles seems to slip too far away from other particles, which is the result of the viscosity a