Apple MA434Z/A User Manual - Page 939

• Slider Low Val: For float and int variables, the lowest value the slider will represent. • Slider Hi Val: For float and int variables, the highest value the slider will represent. 4 When you're done, click OK to create the variable and go back to your project, cancel to close the window without creating a new variable, or next to continue creating new variables. New local variables that you create appear within a subtree at the bottom of the other node parameters. This subtree appears only after at least one new variable has been created, and is named localParameters. Once created, your own local variables can be used and referenced by expressions just like any other parameter in Shake. To remove a local variable: 1 Right-click anywhere within the Parameters tab (not directly on a field), then choose Delete Local Variable from the shortcut menu. 2 When the Delete local variable window appears, choose a local variable to delete from the pop-up menu, then click OK. For a tutorial on using local variables in expressions, see Tutorial 4, "Working With Expressions," in the Shake 4 Tutorials. Expressions The following section provides examples of using expressions (which can help out the lazy compositor by doing your work for you). In any parameter, you can combine any value with a math expression, trigonometry function, an animated curve, a variable, or even a conditional expression. For example, as mentioned above, the center of an image can be found by using: xCenter = width/2 yCenter = height/2 These take the per-image width and height variables and divide them by 2. Chapter 31 Expressions and Scripting 939