An Overview of Dynamics and Maya Nucleus

Dynamics is the simulation of motion through the application of the principles of physics. Rather than assigning keyframes to objects to animate them, with Maya dynamics you assign physical characteristics that define how an object behaves in a simulated world. You create the objects as usual in Maya, and then you convert them to dynamic bodies. Dynamic bodies are defined through dynamic attributes you add to them, which affect how the objects behave in a dynamic simulation.

Dynamic bodies are affected by external forces called fields, which exert a force on them to create motion. Fields can range from wind forces to gravity and can have their own specific effects on dynamic bodies. You’ll learn how to use fields later in this chapter.

In Maya, dynamic objects are categorized as bodies, particles, hair, and fluids. Dynamic bodies are created from geometric surfaces and are used for physical objects such as bouncing balls. Particles are points in space that have renderable properties and that behave dynamically. Particles are used for numerous effects, such as fire and smoke; they’re also useful in tons of other situations and, as such, are a specialty of their own for professional animators. We’ll cover particle basics in the latter half of this chapter. Hair consists of curves that behave dynamically, such as strings. Fluids are, in essence, volumetric particles that can exhibit surface properties. You can use fluid dynamics for natural effects such as billowing clouds or plumes of smoke.

Nucleus, which was introduced in Maya 8.5 with nCloth, is a more stable and interactive way of calculating dynamic simulations in Maya than the traditional dynamics engine. Nucleus speeds up the creation and increases the stability of some dynamic effects in Maya, including particle effects and cloth simulation (through nCloth).

In the Maya 2009 release, Autodesk introduced nParticles. They’re closely related to traditional particles in Maya but have been made easier to create and manage, requiring less explicit expression controls than before.

We’ll introduce nParticles (instead of traditional particles) later in this chapter; however, soft bodies, hair, nCloth, and fluid dynamics are advanced topics and won’t be covered in this book.