Activate BP upon entering trigger box


I’m new to the UE and I’m making my son a video game. Within this game is a room, in which burning pillars are going from one side to another (BP_Obstacle). What I’m trying to achieve is that the pillars are stationary and only start moving once the player collides with the trigger box at the entrance of the room. Otherwise, the pillars are moving from the moment I hit Play. Is that even possible? To “call” (or activate) a certain BP through a trigger box?


Select the trigger.

In the level BP, right click on the graph, near the top is a reference to the trigger.

You’ll want to use an ‘on overlap’ event here, and when the player overlap, use GetAllActorsOfClass ( burning pillar ).

Then foreach pillar, you can call the start move event.

Aye, quite possible. The most straightforward way would be to script it in the Level Blueprint (there are many other ways, though).

  • lets say this is a moving pillar that is yet to be activated:


  • assuming they have already been placed in the scene as needed, open the Level Blueprint and reference those actors:

  • right click the Trigger Box in the world outliner and add an event:

  • add the rest of the script:

  • the above should result in:

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Hey, that was my morning warm up! :innocent: Back to work now…

Yes, I’m not at a machine, so words only… :-/

Thanks for the replies, fellas. Unfortunately, I am evidently stupid …
Just for the reference, this is the BP for the pillar. I followed one tutorial on how to make the back-and-forth movement using start and end points. Would it be even possible to do this with this BP? Or should I rather rework it altogether?


Just replace begin play with a custom event ‘start moving’.

Then from the trigger box call ‘start moving’ for all pillars on overlap.

Thank you for your help. You’re awesome, lads!


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