When you create any type of emitter, a particle object is also automatically created and connected to it. Emitters can be points (CVs, vertices), surfaces (NURBS, polygons), curves (NURBS curves) or volumes (spheres, cylinders).
With volume axis fields, you can funnel or swirl particles within the boundaries of common volumetric shapes. Although this lesson showed how to use a pair of volume axis fields to control the motion of particles, Maya has several other types of fields such as Gravity and Turbulence for simulating natural phenomena. You can use the fields to animate the motion of curves and surfaces in addition to particles.
You can also change ramp colors by editing other ramp attributes, such as Noise and Noise Frequency. To do so, right-click the attribute box for rgbPP, then select arrayMapper1.outColorPP > Edit Ramp. See the Maya Help for details on ramp attributes. You can also control other particle attributes with ramps; for example, opacity. See the Maya Help for more information.
The majority of particle rendering types are visible only when using the hardware render. Software rendering does not display them. However, if you use a particle render type of Blobby Surface, Cloud, or Tube, you must render the particles using the software renderer as hardware rendering does not display those types.
If you create a scene that includes both particles and geometric surfaces, you may need to render the scene twice, once with hardware rendering and once with software rendering. In such cases, you’ll need to composite the two sets of rendered images using a compositing software package.