Eating memory while in Blueprint breakpoint

Development Programming & Scripting Blueprint
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I’m very new to Unreal Engine, and have made a simple Blueprint to move the a player on one axis when I press W or S. This is purely an experiment to get familiar with the engine.

Of course, I did something wrong and the ship doesn’t move. I put a breakpoint on my SetWorldLocation node so I could see what was going on. After under a minute of hitting the breakpoint, the app would freeze on me, and I’d have to kill it and restart it. Finally, at one point macOS told me that I had run out of application memory. Reproducing this again with Activity Monitor running showed UE rapidly allocating memory and never freeing it.

Steps:

  1. Open Activity Monitor, Memory tab, sorted by Memory
  2. Open my project in UE
  3. Open my PlayerPawn Blueprint in the Blueprint Editor
  4. Add breakpoint to SetWorldLocation node
  5. Click Play
  6. “W” to move my ship, thus causing the breakpoint to be hit.

Now just wait, and watch the memory usage in Activity Monitor. It rises from 1.2 GB to 5+ GB over ~30 seconds. I am doing nothing during this time, just watching the memory go up in Activity Monitor. Stopping the debugger releases the memory immediately.

This is a very, very simple project, with a simple blueprint based on the TwinStick template. I can easily upload it if someone wants to look at why its freezing.

Thanks!

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Link to the project. It’s 1.1 GB (I just zipped the whole project dir), so let me know when you have it so I can remove it from my Dropbox: Dropbox - File Deleted - Simplify your life

In the short term I worked around the problem with Print String nodes (turns out I just had the movement speed set way too low, and the code works). A friend of mine was able to reproduce the problem on his system as well, so it’ snot just me. :slight_smile: But it does seem specific to this Blueprint, as he has been debugging other Blueprints and not seen this problem.