My blueprint meshes keep dissapearing, a bug or have I done something wrong?

Development Asset Creation
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1

I have created a very simply blueprint that has 3 static meshes and a single point light. In my event graph I am lerping the intensity of that point light to give off a flickering effect.

event-graph
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the-torch
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The blueprint works from the perspetive that the light flickers as expected. I’ve placed it around my scene and started to notice that when I load or build my project the blueprint meshes are not visible; they are still registered in the world but they vanish.

present
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Placed in the scene, no issues.

vanished
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On build…vanishes

Have I done something wrong here or is this a bug or potentially even a resourcing issue in that the scene is perhaps too big for my computer to handle?

2

Hey! I apologize for not answering your actual question…

If you are going to create a flickering light for your game, I highly suggest looking closer at light function shaders. The method you are currently trying to use will be very expensive if you have many lights.

Here is a tutorial about the subject: Light Functions and Flicker UE4 - YouTube

3

Thanks for the comments, although it doesn’t really help me with my current problem :smile:

4

you could try checking where that mesh center point is. maybe is a culling issue. unreal thinks that the mesh should not be visible because the position is in the back.

also try without the light. maybe you have too many lights and unreal deletes part of them to keep the light count low :man_shrugging:

5

Ok so I’ve been playing with this over my afternoon to try and understand what is going on. I’m starting to think this might be a bug but I’d need someone else to test.

image02
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The issue only occurs with blueprints. Here are my trouble shooting steps so far:

  • Torch C: Placed the original flickering torch blueprint in the scene.

    • Disappears when building lighting. When you play or simulate the level the torch appears again and then vanishes once you stop.

  • Torch A: Created a new blueprint with no event graph logic and placed it in the scene.

    • Disappears when building lighting. When you play or simulate the level the torch appears again and then vanishes once you stop.

  • Torch B: Created a new blueprint with no point light actor and no event graph logic and placed it in the scene.

    • Disappears when building lighting. When you play or simulate the level the torch appears again and then vanishes once you stop.

  • Torch D: Added the same static meshes used in the blueprint to the scene in the same configuration (rotation, scale etc)

    • Does NOT disappear when building lighting. When you play or simulate the level the torch remains. No issues.

image01
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In alignment with @dorusoftware comment, I tried moving the meshes within the blue print above the red light to ensure no culling was happening; the output was the same in that the blueprint vanshed from the scene. I also removed things like the post process volume just in case.

image04
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So, from what I’ve seen it’s the blueprints that cause the problem although I still don’t know why.

Update:

  • Adding a blueprint with nothing more than a sphere causes the same behavior, therefore it’s not specific to the meshes that I’m using.
  • Loading another level within my project and then flicking back to the previous one shows all blueprints in the level without problem (until you build again obviously)

Update:

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