Creating an nParticle system

In this part of this lesson, you create an nParticle object and its emitter object. An emitter controls the position, direction, quantity and initial velocity of the emitted nParticles when they are born (emitted into the scene).

Creating an nParticle and emitter object

To create an nParticle and emitter objects

Select nParticles > Create nParticles > Cloud.

Selecting Cloud presets some nParticleShape attributes that are suitable for simulations such as smoke, dust, or fog.
To create an nParticle emitter object, select nParticles > Create nParticles > Create Emitter > .
The Emitter Options (Create) window appears.
In the Emitter Options (Create) window, select Edit > Reset Settings.
In the Emitter name field, type Emitter_Smoke.
Naming your emitter object makes it easier to identify in the Outliner when you want to select it and make attribute adjustments.
From the Solver list, select Create New Solver.
Selecting a solver determines which Maya Nucleus system your nParticles belong to.
In the Basic Emitter Attributes section, set the following:
- Emitter type: Directional.
- Rate (particles/sec): 120
  This sets the number of particles that are emitted into the scene. The higher the emission rate the thicker the smoke appears.
In the Basic Emission Speed Attributes section, set the following:
- Speed: 2.5.
- Speed random: 5.0.
  When Speed random is set to a positive value, the emitter generates random speeds for each nParticle.
Click Create.
An Emitter_Smoke1, nParticleShape1, and a nucleus1 node appear in the Attribute Editor.
To rename the nParticle object, in the Outliner, double-click nParticle1 and type nParticle_Smoke then press .
Renaming your nParticle object makes it easier to identify when you have more than one in your scene.

Moving the nParticle emitter

When you create an nParticle and emitter objects, they are placed at the scene origin. For this lesson, you need to move the emitter so that the particles are emitted near the tip of the cigarette.

To move the nParticle emitter object

In the Outliner, select the Emitter_Smoke1 object.
Display the Channel Box by clicking .
In the Channel Box enter the following values:
- Translate X: 49.3
- Translate Y: 121
- Translate Z: -27.3
In the scene view, dolly and tumble so that you get a close-up view of the cigarette.
The nParticle emitter is now positioned near the tip of the cigarette.
Play back the simulation.
nParticles are emitted from the end of the cigarette, however, they moving along the X axis and away from the cigarette. This is because the force of the Nucleus Gravity is not yet affecting the nParticles. By default, the Cloud type nParticles are created with Ignore Solver Gravity on, so you need to turn this option off.
In the Outliner, select nParticle_Smoke.
Open the Attribute Editor by clicking .
In the Attribute Editor, click the nParticle_SmokeShape tab.
In the Dynamic Properties section, turn off Ignore Solver Gravity.
Play back the simulation.
nParticles are emitted from the end of the cigarette, however, they are falling down and out of the scene. This is because the force of Nucleus Gravity is negative, so it pulls the nParticles down. You must change the direction of gravity to force the nParticles up.
In the Attribute Editor, click the nucleus1 tab.
In the Gravity and Wind section, change the Gravity Direction for Y from -1.0 to 1.0.
Play back your simulation.
The smoke now rises.