xpDirection controls a particle’s direction of travel.

Object Properties

Object tab menu for xpDirection.

Enabled

Enabled by default.

Uncheck to disable xpDirection.

Mode

Set at Independent, by default.

You can change this to Action-Controlled.

Independent Mode

In this mode, particles will be affected if they come into the field of effect of the modifier.

Action-Controlled Mode

When in the Action-Controlled Mode setting, the modifier will only act on a particle when told to do so by an action.

Visible in Editor

When checked, the direction for the particles will be shown by an arrow in the viewport.