Transitions

Transitions move your story from one state to another. In essence, when one clip in your story finishes playing, a transition determines which clip will play next.

Transitions are represented in the Graph Editor by arrows leading from a source state to a target state. You can also have multiple transitions from a single source state to different target states.

A Transition Arrow

By default, a transition happens as soon as the source state is "done." But you can control when to follow a transition by using events, actions and conditions.

Creating a Transition

Notice that, when you hover your mouse over the right-side end of a state node, the end section changes color. This is where you start dragging a transition arrow.

Dragging a New Transition

Click on your new transition arrow to see it’s properties in the Properties window. The properties are described below.

Note that you can use a transition to loop back to an earlier state in your story. This can be useful if you want to go back and replay a series of clips.

Transition Loop to Previous State

Properties of a Transition

With your transition arrow selected in the Graph Editor, you will see its properties displayed in the Properties window. They are described below.

Transition Properties

Source and Target

The names of the source and target states in the Story Graph.

On Event

Events are messages that are broadcast to your story when certain things happen, like a state finishes playing its clip, or the viewer turns their camera towards a trigger.

You can use these event messages to determine when to launch a transition. If you click on the pull-down menu next to On Event, you will see the different types of events you can use.

Important: If you set both On Event and Conditions, your transition will happen only when both of these requirements are met.

For more information on events and how to use them, see Events.

Action

When you launch a transition, you can also choose to launch an action. For example, you can use an action to play a sound, move a camera, or even exit the story.

Click on the pull-down menu under Action to set the type of action you want. If there are other parameters to fill in for that action, they will appear below the type.

For more information, see Actions.

Conditions

It may be that, when you reach the end of a state, you don’t want to transition immediately to the next state. Besides setting your transition to wait for an event message, you can also set a condition. A condition can act as a mask, which can prevent a transition from proceeding. For example, you may want your transition to wait for a specified amount of time, or until the viewer is looking at a specific trigger in the scene.

Click on the pull-down menu under Condition to set the type you want. If there are other parameters to fill in for that condition, they will appear below the type. When you set a condition, a "C" icon appears on the arrow in the Graph Editor.

Transition Condition

Important: If you set both On Event and Conditions, your transition will happen only when both of these requirements are met.

For more information on each of the conditions you can set, see Conditions.

Interrupt

By default, when the events and conditions for a transition are met, the transition waits until the source state finishes playing through its frame range, or its specified number of loops, before launching. Normally this makes sense, since leaving a state in the middle of a clip might lead to discontinuity in your animation. However, interrupting a state’s run may be exactly what you want, especially if the state has no associated animation clip.

If you check the Interrupt checkbox, the transition will launch immediately when it receives the events and conditions it is waiting for.

Sync

If you enable this option, the target state of a transition will start at the same point in its duration that the source state finished. So, for example, if the source state is 80% complete when the transition starts, the target state will begin 80% of the way through its duration.

This might be useful when, for example, you want to change some parameters in the middle of an animation. You could set up source and destination states to run the same animation. Then when you transition from the source to the target state, the parameters will change, but the animation will continue without interruption.

Pending Download

As your story plays, resources for upcoming states are being downloaded and prepared. If not all the resources for a state are ready when that state starts playing, it might affect the smooth playback of the story.

If you enable this option, the transition will wait until the required resources are downloaded and prepared. Those resources are from both the target state and, possibly, the states it transitions to. Consequently, if the target state has transitions to many possible states, the Pending Download option might cause a noticeable delay.