If your nParticle object emits particles (has an attached emitter node) you can control some emission settings using the nParticleShape node’s Emission Attributes. Most emission properties, such as initial position, direction, quantity, and speed of the emitted particles, are controlled by emitter node attributes. For information about emitter node attributes, see Work with emitters in the Dynamics guide.
To set nParticleShape node Emission Attributes