Graphics Programs Reference
In-Depth Information
playback. You can also scrub your timeline to see your particle animation. If you make
changes to your animation, the scene won't reflect the changes until you delete the cache
from memory by selecting the particle object and unchecking the Memory Cache check
box in the Attribute Editor. The amount of information the memory cache can hold
depends on your machine's system RAM.
Although memory caching is generally faster than disk caching, creating a disk cache
lets you cache all the particles as they exist throughout their duration in your scene and
ensures that the particles are rendered correctly, especially if you're rendering on multiple
computers or across a network. You should create a particle disk cache before rendering.
If you make changes to your particle simulation but you don't see the changes reflected
when you play back the scene, make sure you've turned off any memory or deleted any disk
cache from previous versions of the simulation.
Creating an nCache on Disk
After you've created a particle scene, and you want to be able to scrub the timeline back
and forth to see your particle motion and how it acts in the scene, you can create a
particle
nCache
to disk. This lets you play back the entire scene as you like, without running the
simulation from the start and by every frame.
To create an nCache, switch to the nDynamics menu, select the nParticle object, and
choose nCache
➔
Create New Cache. Maya will run the simulation according to the time-
line and save the position of all the particle systems in the scene to cache files in your cur-
rent project's data\cache folder. You can then play or even scrub your animation back and
forth, and the particles will run properly.
If you make any dynamics changes to the particles, such as emission rate or speed,
you'll need to detach the cache file from the scene for the changes to take effect. Choose
nCache
➔
Delete Cache. You can open the option box to select whether you wish to delete
the cache files physically or merely detach them from the current nParticles.
Now that you understand the basics of particle dynamics, it's time to see for yourself
how they work.
Animating a Particle Effect: Locomotive Steam
You'll create a spray of steam puffing out of the steam pump on the side of the locomotive
that drives the wheels on the model you started creating in Chapter 4, “Beginning Polygonal
Modeling,” and Chapter 5, “Modeling with NURBS, Subdivisions, and Deformers.” You'll
use the more detailed locomotive model from Chapter 8, “Introduction to Animation,”
and Chapter 9, “More Animation!”
