DFGI and ray trace causes projects to crash

I’m not entirely sure if this is just me but I noticed with the release of 4.15 that enabling ray trace on any light source in the project will cause it to crash upon re-opening unless the option is re-disabled in the config file. I had an earlier project that was utilizing dfgi on 4.13 that worked perfectly fine without crashing, even with ray trace enabled lights.

Hey Jimonions,

I just ran a test in a new blank project on three different light types (spot, point, and directional), but none of them crashed after I enabled RayTraced DistanceField Shadows.

We ask that whenever users report a crash they provide us with steps to reproduce the crash in a blank project, and the crash logs and ‘dxdiag’ of the machine you are using.

Let me know if you have further questions or need additional assistance.

Thank you,

Sorry I forgot to mention this was in a new project. I replicated it again step by step today with the same results.

  • enable dfgi in default config file nothing else changed.
  • startup new project on 4.15 with third person base.
  • project is working fine
  • go into project settings and untick static lighting and tick generate mesh distance fields
  • go into world settings and tick force no precomputed lighting
  • save and restart
  • everything works normally still
  • enable raytrace shadows on directional light, no crash yet.
  • click play and project crashes
  • project continues to crash from this point on until dfgi is disabled.


Hey Jimonions,

DFGI isn’t a supported feature in its current state. The issue you are posting is acutally known and we have a ticket for it that is closed currently. Once this feature is released as an “official” part of the engine we can start addressing issues like this.

You can find the ticket here: Unreal Engine Issues and Bug Tracker (UE-40449)