In This Chapter
Special effects can grab viewers' attention and rivet them to the story you are telling better than almost any aspect of computer animationif it is done well. Gratuitous special effects, however, can get in the way of a good story and distract from the focal point of your work. You will learn to set up short collision effects scenes that can enhance a storyline and still be cost effective in production time.
This chapter introduces you to a new feature: Reactor. Reactor is a rigid body and soft body dynamics system that calculates the collision of moving bodies in your animated scenes. You will work through two different scenes involving collisions to show you typical uses for the Dynamics system. In one scene, you try to catch a barrel fired from a catapult in a net strung across the street, as an example of rigid bodies interacting with cloth realistically. In another scene, you animate a transporter being thrown from the local palm reader's shop and reacting to the hanging beads in the doorway to learn about the interaction of rope objects, rigid bodies, and Reactor attachment modifiers.
Using the Dynamics system instead of hand-animating similar effects can save production time. Among the concepts and techniques you will learn are
Rigid bodies Classifying and grouping rigid bodies that are inflexible or unyielding often set the basis for collision detection.
Cloth collections These flexible, draping, open-edged objects can interact with other elements in the scene.
Rope collections This group of objects collides like strands of rope and can be attached to other objects.
Mass properties Assigning mass properties to objects gives them weight and friction so that they interact believably with other objects in collisions.
Keyframes and Dynamics animation This method enables you to animate objects to set their velocity and then pass the control to collision detection.
Background image Acts as a backdrop in your scene with very little overhead in computer resources.
Matte/Shadow material This material makes an object invisible in the rendered image, but allows a background image to show through and receives shadows from other objects. With this material, you can use a simple box object, for example, to represent a street in a collision scene.
background image An image displayed as a backdrop in the rendered image or in the display viewports. This is a basic form of compositing a 3D scene against a 2D background to save rendering time.
Cloth Animated open-edged surfaces with no thickness that simulate draping cloth in collisions with other objects in Reactor.
Reactor A plug-in included with 3ds max 5 that calculates collisions between objects in an animated scene.
Reactor collection A grouping of objects to be included in a Reactor collision detection simulation. Rigid Bodies, Rope, and Cloth are some of the collection types.
Rigid Bodies A class of Reactor objects that have inflexible surfaces and can be unyielding to other objectsfor example, a road or floor surface.
Rope A fixed-end or free ropelike structure used in Reactor collisions.
Hotkeys and Keyboard Shortcuts
m Open the Material Editor
Shift+Q Quick render
F10 Render scene