Adobe 12040118 Using Help - Page 4

Help Using Help Overview Back 4 Motion math is no longer included in After Effects; its functionality has been superseded by scripting and expressions. All mathematical and logical operators common to ECMAScript are available in scripting. For example, with expressions it is possible to simulate the physics of a a bouncing ball by applying mathematical rules to a "ball" layer. But using scripting, you can create a whole user interface that allows a bouncing ball and shadow layer to be animated using criteria entered by the user. About this guide This guide is for users who manage a graphics pipeline (which may include other scriptable applications as well) and who want to write scripts to add custom capabilities to After Effects. This functionality is also offered via third-party network rendering management solutions. These products feature software designed to help manage this process, so it is possible to take advantage of this functionality without having to perform manual editing of scripts. Although this guide is intended to provide an understanding of the extensions that have been added to the ECMAScript/JavaScript language for scripting of After Effects projects, to take full advantage of what is possible with scripting you will also need an understanding of writing scripts at the system level (for integration with AppleScript on the Mac and DOS shell scripts on Windows systems) and a background in how to work with JavaScript. Much of what scripting can accomplish replicates what can be done via the After Effects user interface, so a thorough knowledge of the application itself is also essential to understanding how to use this functionality. Note that JavaScript objects normally referred to as "properties" are consistently called "attributes" in this guide, to avoid confusion with After Effects' own definition of a Property (an animatable value of an effect or transform within an individual layer). Activating full scripting features For security reasons, the scripting features that operate outside the After Effects application (such as adding and deleting files and folders on volumes, or accessing the network) are disabled by default. To enable these features, choose Preferences > General, and select Allow Scripts to Write Files and Access Network. By selecting this box, you enable the following: • Writing files • Creating folders • Setting the current folder • Creating a socket • Opening a socket • Listening to a socket The JavaScript Debugger is disabled by default so that casual users do not encounter it. When editing or writing scripts, the JavaScript Debugger can help you diagnose script problems more quickly. To activate the JavaScript Debugger on the local machine when a script error is encountered, choose Preferences > General, and select Enable JavaScript Debugger. Note that the JavaScript Debugger operates only when executing a script, not with expressions, even though expressions also make use of JavaScript. Using Help Back 4