Creating Expressions

You can create an expression in different ways, depending on how complex it is and which tools you want to use. You can create simple expressions using the explorer, parameter connection editor, or property editor, as described below, or write more complex expressions using the expression editor, as described in Writing Expressions.

You cannot create an expression on a parameter that already has other animation, such as a function curve or another expression. You must remove the existing animation first — see Removing Animation.

However, you can combine expressions and other animation using actions and the animation mixer (see Storing Expressions [Nonlinear Animation in the Animation Mixer]). Using a similar method, you can also have more than one expression on a parameter — see Multiple Expressions on the Same Parameter.

Creating a Default Expression

A default expression is simply an expression that states the selected parameter's current value.

To open the expression editor and create a default expression

You can use the Set Expression command in either of the following ways.

In the explorer or a property editor, right-click a parameter's animation icon and choose Set Expression. In the explorer, you can also right-click the parameter's name and choose this command.

or
Mark one or more parameters, then choose Create Parameter Set Expression on the Animate toolbar or Animation Set Expression from the Animation panel.

Creating an Equal (=) Expression

While writing expressions allows you to create more complex expressions, you can also create simple expressions easily using any of the following methods.

In a property editor, drag unanimated parameter A's animation icon onto parameter B's animation icon. Parameter B's animation icon shows an equal sign in it and its value changes to be equal to Parameter A.

If there is already animation on the animation icon being dragged, the animation is copied to the other parameter, but no expression is set.
Press Ctrl when you drag and drop the animation icon to create the equal expression without opening the expression editor.

In the explorer, drag the name of an unanimated parameter and drop it on another parameter's name.

In the parameter connection editor, select one or more parameters as the Driven Target and a single parameter as the Driving Source, then select Equals (=) Expression from the link list and click the Link button.

See Linking to a Single Driving Parameter for more information.