Introduction

A field is a grid of voxels. A voxel is a 3D pixel that contains the following data:

  • “Ink”RGBA Colour information
  • “Movement Vector”XYZ Vector

By holding colour / “ink” information in the voxel, we can render it, like a drop of ink suspended in a liquid or a puff of cloud. By holding a vector of movement we can simulate complex fluid-like motions through the grid.

With every newly rendered frame, the simulation of the field is stepped forward. During this simulation step, each voxel calculates it’s movement vector by understanding how the movement of the surrounding voxels are affecting it. For example, if a voxel to the left has a movement vector pushing to the right it will transfer some of its movement into the voxels to it’s right. In this way, it simulates the real world of motion in liquids or gases.

Likewise, in each step of the simulation, a portion of the ink follows the direction of the movement vector.

The way voxels are rendered can vary greatly, allowing smoke, clouds or more solid forms.

There are three primary types of field nodes:

  • Emitters, these emit colour / “ink” into voxels in the grid.
  • Affectors, these add movement to the “movement vector” of voxels in the grid.
  • Rendering, these nodes render the voxels of the field in different ways.

You can also use the Movement Vector data from the field to affect particle systems using the Particle -> Affectors -> Field Affector node. This is very useful for fluid-like particle simulations.

Method

Field nodes are nodes used in a Field system. This system starts with a Root node, and is built out with Emitter and Affector nodes, before finally being rendered to the camera with a Rendering node.

Fields are generally hooked into the Root node, although they can be applied to any node – they will still appear in the scene as long as there is a path to a Root node; they will inherit the transformation values of parent nodes.

Some commonly used terms

Node Spawn Mode

The shape of the affector falloff.

Mode Description
Point The affector falls off in distance from a point.
Line The affector falls off in distance from a line.
Plane The affector falls off in distance from a 2D plane.

Gallery

Affectors

Curl Noise Affector Fluid Affector Image Affector Primitive Affector Turbulence Affector
Velocity Affector Vortex Affector

Emitters

3D Object Emitter Image Emitter Particle Emitter Primitive Emitter

Rendering

Field Lighting Field Renderer Field Shadows Render To Object Surfaces