The Volume Axis field lets you move objects, including particles and nParticles, in various directions in a volume. The motion imparted on the object is relative to the axis of the volume.
You can use the Volume Axis field to create effects such as particles flowing around obstacles, solar flares, mushroom clouds, explosions, tornadoes, and rocket exhaust.
For example, you can specify the speed at which particles move around the central axis of a volume. If you use a a cylinder volume shape, this can create swirling gaseous effects.
The Volume Axis field provides most of the volume speed controls of the volume emitter in the form of a field, and its attributes work just like the corresponding volume emitter attributes. You can also invert the attenuation (see Invert Attenuation).
Like the volume emitter, the volume field draws arrows to illustrate the speed values you have set. These are not manipulators. As with the emitter, you can turn them off, if you wish. See Fields > Volume Axis. You can create a volume axis curve by selecting Fields > Volume Curve. See Work with volume axis curves.