Toss That Ball, Fire That Gun, Shoot That Arrow; Projectiles in 3D Games, Part 1

April 8, 2002
by Allen Partridge

In this series of articles, I'll explain the basic elements involved in shooting 3D objects of varying velocities and trajectories toward targets. I'll also demonstrate a collision system that takes advantage of Director's native 3D collision modifier. If you thirst for more you'll probably find it in my book, Real-Time Interactive 3D Games: Creating 3D Games with Macromedia Director 8.5 / Shockwave Studio. In the book I describe various implementations of projectiles and collision in greater detail.

By reading and understanding this article you should:

learn the process of creating model resources dynamically;
learn the process of creating models dynamically;
learn the process of creating and manipulating shaders dynamically;
learn how to tile textures;
learn how and why to subtract vectors;
learn how to perform math functions on #rgb color objects;
learn to work with the pointAtOrientation property of a model;
learn to work with the pointAt command;
learn to work with the collision modifier and collision callback objects;
find the basic formulas for simulating the effects of gravity, drag, and force on a 3D model.

Conversely, you will not learn anything about making the shooting aspect of your game exciting or engaging, from the technical information found here. This tutorial is meant only to provide you with the technical information related to animating projectiles. I would be hard pressed to make a game less engaging than this demo.

Sample Director 8.5 movie source is available for download in ZIP or SIT archive format (each file is approximately 70K). Before we begin, amuse yourself for a moment tinkering with the demo movie. (6K, Requires Shockwave 8.5)

Figure 1.1. Demo Simulating Projectiles, Gravity and Collision.

Al Partridge is an independent game developer, host of dirGames-L, and Professor of Dramatic Media at The University of Georgia. Partridge's recent publications include Real-time Interactive 3D Games: Creating 3D Games in Macromedia Director 8.5 Shockwave Studio.