The vector-field sampler (also named turbulence sampler) allows you to sample vector-fields from procedural curl noises or on-disk files. It is useful to fake fluid movement, such as particles of smoke, sparks, or ashes, flowing through a turbulent medium:

Turbulence affecting particles physics

Vector fields are sampled with a 3D position and return a 3D vector.

Vector field samplers are most commonly used with the following templates:

• Physics
• TurbulenceSample

Note: If you need a coherent random-looking value, you can use the Noise node or script function instead of the vector field sampler set to ‘procedural’ mode: It will be much cheaper during simulation.