Okay, so, okay, I'm posting this because I spent the last day googling "playmaker raycaster", "playmaker cardboard gazeInput", "playmaker event manager", and not finding what I needed. I hope to spare someone else that fate.
For my current gig it's necessary to avoid all scripting, so I was pulling my hair out trying to use standard PlayMaker actions to inspect Cardboard's GazeInput Module. This is the official way to make Cardboard detect whatever the user is currently looking at. It involves InputModules and EventManagers and Raycasters and custom-scripted Event responses... ugh. I was taking each of those and fussing with "Get Property", "Get Component," and even "Call Method", etc, etc all day, trying to find what I needed.
I'm here to say that, as usual with Playmaker it is SO EASY.
Here's all you need:
1. Whatever object you wish to turn into a gaze trigger, make sure it has a Collider component. Note that you *don't* have to check "IsTrigger"--it will work anyway.
2. Attach Playmaker's Raycast action to an FSM in the MainCamera inside Cardboard's Head object.
3. On the Raycast action, set Direction to X: 0, y: 0, Z: 1. This makes the raycast always aim directly forward from the Main Camera.
4. Set the Hit Object and Hit Event to any variables you like, and you're done!
Man oh man, all that complicated GazeInput was stuff duplicated with ONE Playmaker action. I wish I'd found it before wrestling with the official process for so long. But I hope this post helps anyone else in my position!
p.s. Cardboard is cool.