How do I message across objects with blueprint?

I have made a puzzle for a game in which you slide a cube into a hole to open a door. I have got it so I have the door, the trigger and the cube, and gotten the puzzle to work, but I can’t figure out how to have the trigger send a message to the door for it to open. How do I do this? Do I use gamestates, and if so, how do I make one?

Posting screenshots that show your blueprint setup will help me better assist you.

If your door is already spawned in the level I would have a public accessible variable on the trigger that contains a reference to a door Actor. In the level designer when you select a trigger you can set the door reference variable.

You can create a blueprint that has the items you are using within its component tree.
From here operating a given reference based on the trigger activity is a natural thing.

So you have the Door and a collision box as a minimum in the blueprint, you would configure the trigger to recognize the block using the collision callbacks (begin actor overlap / end actor overlap)

But as elitereloaded suggested, screen shots of your configuration are a good place to start with getting recommendations.

alt text

Yes, so now add a box collision object to your component tree using the green button on the upper left side above the component tree.

From there you can implement begin/end overlap methods to react as you please.