Lighting won't update while playing preview?

Hello, its me again. :slight_smile:
I have a question concerning Lighting. I have a Custom Blueprint Pointlight, that I want to turn off using Blueprints (light switch)
I have tried two variants so far:

  1. Turning down intensity and attenuation Radius (the last is important because it determines something in my blueprint considering a light shadow mechanic)
  2. Simply Destroying the Actor

First one didn’t work at all - the light just stayed the same and I was still detected while walking into it.
Second one deleted the Actor, but the lighting in the Engine didn’t update. :confused:

The Point light in my blueprint is a stationary one, so it can theoretically be updated during runtime.

Is it common for the preview of UE4 not to update dynamic lighting and lighting changes? :confused:

Will this go away when I export the Project?

Its a bit stupid for testing purposes, and I really hope I can somehow get rid of the lighting artifacts …

Please help ! ; _ ; Thank you in advance!

Have a read here: Stationary lights

In short: you can only change Brightness and Color of the Stationary light. Keep in mind tho, this only affects direct lighting and everything you already baked into lightmap will stay as it was!

Generally for dynamic lights that are supposed to turn on/off you should consider Movable

Thank you! I did try it out with movable, it still didn’t work. I had to turn off all prebaked lighting in the world settings … ._. only then it wouldn’t pre bake lightmaps that couldn’t be changed anymore - if you have a better solution though, please let me know, I’m not a fan of having to turn off lightmaps completely.

Movable shouldn’t be baked into lightmaps, but there might be a different light source / lightmap settings that causes that area to be lit even tho you switch the Movable light off. Is the area getting dark, as expected, if you set Visibility of that light to off in the editor?

Things to consider:

  • Check the lightmap settings
  • Check for additional light sources that would affect the area in question (this can be emissive or very bright surfaces as well!)
  • Adjust material lightmap settings
  • Switch to fully dunamic lighting, disable lightmaps completely and use real time GI instead (need to enable it in the PostProcessVolume)

The obvious disadvantage of fully dynamic is the performance cost, but for some games / scenarios it’s the only way.

Edit:
Just to make sure you’re aware of this, lightmaps cannot be changed during the game, that’s the whole point of pre-baking it in the editor, so that you do all calculations beforehand and reduce the performance impact as much as possible during play.