Join Aaron F. Ross for an in-depth discussion in this video Creating an nParticle volume emitter, part of Maya: Particle and Fire Effects (2011).
Now, we are ready to add nParticles to the scene. N stands for Nucleus and Nucleus is Maya's advanced dynamic engine. The idea of Nucleus is all the parts sort of fit together and you can have particles interact with cloth and so on and it's very cool and it's very advanced. We're really only going to be using some of the most basic features of nParticle in this exercise. First thing we'll do is go to the nDynamics menu set, then to nParticles menu, and under Create nParticles you'll see that there are some presets here and yours is probably going to say Cloud.
Just go ahead and click on Points. Then in the second step we will go back into that same menu, Create nParticles. We want to create an emitter. I'll go into the Options box for the nParticle emitter and make sure that the Emitter Type is Volume. Yours will probably say Omni. We want to make sure that it says Volume emitter. And scrolling down a little bit you'll see that the Volume Shape is Cube and that's what we want.
Go ahead and click Create. It's created at the origin. I will go ahead and grab the Move tool and pull it a little bit closer to the camera. You'll also see this big N. That's the Nucleus node and it doesn't matter where the Nucleus node is in the scene and it doesn't even matter if it's visible but it's there. All right! So getting a little bit closer into the camera, here is the emitter and I just want to position it so that it's not visible to the camera.
I don't need to drop snowflakes over my entire world. Just right up close to the camera is fine. In my Perspective view I will press the F key and frame that to get in closer. I am going to set the emitter to about maybe 15 units above the ground plane and maybe about 90 units, so that it's about 15 units away from the camera itself. I will also need to scale the emitter. I can just go ahead and grab the Scale tool and scale that up in X maybe about 10 times size, and I also want to scale it in Z to maybe about 5 or so.
It's approximately about the right size for the emitter. Now that that's been done, let's take a look at what we get when we press the Play button here. So we already get something. Notice that they're falling of their own accord and that's sort of what happens with Nucleus because Nucleus has gravity built into it. Let's go to the Outliner and select the Nucleus node. Hit Ctrl+A to go to the Attribute Editor. So we can see the Nucleus node attributes and you can see there is an Enable switch here.
I can turn it on and off, and there's Gravity built-in, so I don't need to add a field. The particles will fall without any field. Let's play around with some of the nParticle attributes in here. So I will click nParticle in the Outliner. And currently they're set to Live Forever, so I want to open up the Lifespan and set that to a constant of maybe about 5 seconds. What we want to have happen is the particles will fall through the floor but then after they go through, eventually they'll just disappear and die out.
We are going to add some turbulence and make them blow around a little bit more. When we are finished, they won't fall so far through the floor. Okay, back in the emitter we've got the Rate. I am actually going to knock that Rate down a little bit to about 50 while we are testing this, so that we don't overload the machine. The nParticles or Nucleus particles are a little bit heavier than the classic particles so we need to be kind of conservative about the number that we're using here. Great! So we've got our particles in the scene and next we're going to actually attach a piece of geometry to those particles with the instancer.
- Laying out the scene
- Sketching particles on a Live object
- Connecting particles to Fields such as Gravity
- Emitting particles from particles
- Varying particle shader attributes
- Modeling and shading for the Particle Instancer
- Importing and instancing geometry onto particles
- Randomizing particle rotation with Creation and Runtime Expressions
- Adding Turbulence
- Rendering depth of field with mental ray
- Creating 3D Fluid containers
- Emitting dynamic fluid attributes from an object
- Animating a dynamic fluid
- Using a fluid for atmosphere
- Modulating light intensity with a noise expression