In This Chapter

Sometimes, instead of using the keyframe animation techniques described in Chapter 11, "Animation Basics," you might want to use a feature of Maya called Particle Systems to create motion. Particles can be particularly helpful when you want to create and animate dozens, hundreds, or thousands of similar objects that vary slightly in their geometry or animation. You can also use Maya's Dynamics mode to simulate reality in how objects behave for example, animating the way bowling pins react when struck with a bowling ball. Another feature in Maya's Dynamics mode is the ability to create "soft-body" effects, in which objects deform as though they were made from rubber or gelatin. Some of the topics covered in this chapter include the following:

• Creating rigid-body dynamics simulations Setting up your scene for objects to react to forces and collide with each other.

• Applying forces Dynamics simulations can take into account gravity, wind, and many other types of simulated physical effects.

• Applying constraints Objects might not always be free to fly around; they can be hinged or tied down in many ways, and Maya takes these constraint factors into account.

• Creating particles You can define where particles are created in Maya by painting them or by using particle emitters.

• Particle types Maya offers many unique types of hardware-rendered and software-rendered particles that you can customize to create rain, splatter, or breakup effects, among others.

• Creating soft-body dynamics You'll learn the steps of setting up a soft-body effect so that objects bend and deform when they're hit by other objects or acted on by forces in your scene.

Key Terms

active body Objects that collide and react when collisions occur.

passive body Objects that active bodies can collide with and react to but do not react themselves.

fields Forces such as gravity used to animate the motion of rigid and soft bodies and particles.

constraints A restraint on the kind of motion a Dynamics object is allowed. For example, a hinge constraint restrains an object to rotating on one axis.

emitter A particle source that controls variables such as speed and direction for particles; you can think of the emitter as a hose and particles as a stream of water.

soft body An object that can deform during a dynamics simulation. A soft body object is influenced by a related particle system or emitter. Dynamic collisions move particles, which can then move the soft body.

goal A position target for particles, usually defined by a NURBS or polygon object. The particles seek to distribute themselves on the CV or vertex positions of the goal object.

Hotkeys to Memorize

F4 Dynamics mode.

Alt+h Hypershade.

Ctrl+h Hide selected object.

F4 Switch to Dynamics mode.

This chapter covers a set of tools in Maya that automate animation based on controlled parameters. These tools particles, rigid-body dynamics, and soft-body dynamics are related in how they function and how you control their use. To access them, you need to make sure you're in Dynamics mode in Maya.

These functions dynamics and particles work together to create animation that would otherwise be difficult to hand-key. With rigid-body dynamics, the idea is to simulate physics so that objects collide with each other and deflect. With soft-body dynamics, objects change (deform) as a result of their collisions. With particles, you can easily control the animation of large numbers of objects. For all these functions, you can create forces such as gravity or wind that affect the animation.