nxConstraints - Viscocity

Overview Video

This layer simulates the internal friction within fluid.

It can be used to create gloopy liquids like honey.

For high viscosity simulations it will be necessary to increase the Iterations value.

Weight

The Weight setting alters the influence each constraint type provides to the overall, global solution.

If you are only using one layer, this can be left at the default, 100%.

If you are combining different constraints in several layers, you could reduce this weight to lessen the effects of the connections and blend in other layers.

Connection Limit

A limit on the number of connections each particle can make.

Animation to demonstrate a comparison of the Connection Limit value of 1, on the left, and 5, on the right.

Radius

This is the maximum distance to which surrounding particles are included in the viscosity solution.

This animation is comparing Radius values of 5cm, on the left, and 15cm, on the right.

Stiffness

Much like the other constraints, the stiffness represents how strong the viscosity is.

However, the actual viscosity depends on both this and the Iterations value in the Object Properties.

You can get a higher and more stable viscosity with this at a lower (not 100%) value, together with a higher Iterations setting.

By having a softer constraint and more iterations, you enable the particles to avoid large changes, which can result in instability, especially when solving against other constraints.

In this animation, you can see a comparison of the Stiffness value of 5%, on the left, and 100%, on the right.