An important characteristic of liquids is surface tension. Surface tension is the attractive force between the molecules of liquids, and is most noticeable in phenomena such as the formation of water beads or liquid droplets on surfaces. You can use the Surface Tension attribute to add realistic surface tension to your liquid simulation.

The Surface Tension attribute adds an attractive force between nParticles which keeps them together. The effect of Surface Tension is most visible in liquid simulations after the nParticles object is converted to an output mesh.

To add surface tension

1. Go to frame 115, then dolly and tumble the scene so that you a close-up view of the mesh pouring into the glass.
2. In the Outliner, select Water_Mesh.
3. In the Attribute Editor, click the nParticle_WaterShape tab.
4. In the Liquid Simulation section, set Surface Tension to 0.3.
5. Hide the Water_Mesh object and cache your simulation.

   To cache your simulation, follow the steps in Cache your nParticle simulation. You can replace your existing nCache by selecting nCache> Replace Cache instead of nCache > Create New Cache.

6. Go to frame 122.

   The mesh is noticeably more uniform, and looks more like a flowing liquid.