DFGI will be disabled by default in 4.8, and will remain until we are happy with performance and quality and consider it to be usable. Right now the bounce distance is too small, the performance cost is too large and there are bright spots sometimes where objects meet. It’s very early.
To test it out before 4.8:
- Get latest master branch on (note this is often broken with compile errors and the like)
- put r.DistanceFieldGI=1 in the [Startup] section of Engine\Config\ConsoleVariables.ini\ConsoleVariables.ini
- Enable GenerateMeshDistanceFields in the project settings under Engine -> Renderer, restart editor (same for all distance field lighting)
- Place a movable skylight. This is required even for GI at the moment.
- Place a movable directional light
Check out the DFAO page for restrictions, in particular only static meshes, instanced static meshes (including foliage with opt-in bAffectDistanceFieldLighting) and landscape supported for bouncing lighting.