State machine example: Interactive Tutorials

• The TutorialBuldingDemo file located in the Content Browser.
• The interactive Basics tutorial via the Getting Started tab of Application Home.

To view the state machine

1. In the Outliner, turn off Display > DAG objects only.
2. Filter by the term "stage".
3. Select all the stage nodes.
   Note: There will also be a number of "activate_stage" nodes alongside the stage nodes. You do not need to worry about these yet.
   
4. Open Windows > Node Editor.
5. Click the Show Inputs / Outputs button () to display the stage nodes and their connections.

• On Activate Script: This is the script node where the bulk of each stage happens. You can view the Python code in the Expression Editor (see below).
• On Deactivate Script: Connect a script node here to clean up after a stage once it's finished. It's good practice to try and keep your stage logic self-contained so that it's easy to move them around or insert/delete them as needed. In the example above, it's clear that a stage0_1 was inserted between stage0 and stage1 at some point during development. It can also be handy to design a universal deactivate script that can be used by all stage nodes, allowing you to simply connect all the On Deactivate Script attributes down the chain for readability.
• Time Slider Bookmark: This is handy for setting up animations at the beginning of a stage, but also for changing the state of a scene between one stage to another. For example, you can keyframe the active camera at the start of the bookmark to have the camera jump to a different spot in the scene at the beginning of the stage. Or you can keyframe an object's visibility to have it appear during one stage but not another.
• Stage progression: Depending on the goal of a stage, the way it progresses to the next stage will differ. Some of the most common ways are:
  • Activating the stage's Condition attribute or using the '-next' flag: Use this method when you need to trigger the next stage on any sort of event, such as when the user clicks a button on a custom window or other UI widget, or when they fulfill some sort of condition (e.g. the moving an object into a specific spot, or opening specific editor). In the latter case, you may need to embed the command inside a scriptJob in order to listen for those events.
  • Activating the stage's End of Animation attribute: Use this for stages that are simply demonstrating something to the user. The next stage will activate automatically once the Time Slider is played to the end.
  • Setting a non-zero Delay value: Use this to give a stage a time limit before automatically progressing to the next stage. Useful if you want to give the user a finite time to explore before moving on.
• Displaying 2D text or images on the UI: This is the best way to give instructions and hints to the user. In the example files above, you can find overlay source code in the following script nodes:
  • overlayBubble
  • overlayDialog
  • controller
  There is also a demo included in Maya to show you what else is possible, which you can run with the code:

  import moverlay
  moverlay.mayaDemo.demoOverlays()
  

  You can find the source code for the demo, as well as the moverlay module itself, in the /Python/Lib/site-packages/moverlay folder of your install directory. For more information on 2D overlays, see Displaying 2D Overlays.