While some parameters can be set using the console commands, not all are saved within the .ini file and won't have any effect on restarting the editor. Here are a few very helpful "DefaultEngine.ini" additions:
[/Script/Engine.RendererSettings]
r.Nanite.AllowTessellation=1
Allows nanite tessellation for the project.
Works a bit like the original DX11 tessellation, but while incorporating Nanite (enabled in Material Editor).
Won't affect everything, just like the regular Nanite.
r.Nanite.Tessellation=1
Like AllowTessellation, but not just allows but actually enables Nanite Tessellation.
r.Nanite.DicingRate=16
Affects Nanite density for tessellated surfaces using Materials.
The higher, the less tessellation will be applied (great to tweak performance).
r.PSOPrecaching=1
When loading levels, this is supposed to pre-compile all available shaders to prevent/reduce shader compilation stutters.
Levels will take longer to load for the first time, also depending on the hardware configuration used.
Note: untested and may require some more setup in C++.
[/Script/Engine.Engine]
MaximumLoopIterationCount=100000000
If you know you have loops that are really long, increase this value the game won't exit or give errors on too many iterations counts.
Only change if you know, that there is no way to create shorter loops depending on your projects' needs.
If you're using a Landscape with Nanite, the following Command Lines are quite helpful:
landscape.Nanite.MultithreadBuild
landscape.Nanite.LiveRebuildOnModification
If you're using a NavigationMesh and/or NavigationSystem and the Navigation Tile Debugging isn't working anymore (pressing P and showFlag.Navigation doesn't work) it is likely something is corrupted. You can fix this by going into the Engine folder and deleting the following:
Binaries
Build
Intermediate
An example of the path for the engine folder: C:\Program Files\Epic Games\UE_5.4\Engine
ISMC: Instances Static Mesh Component(s)
doesn't support per object LODs (would be applied to all instances at once)
great for Nanite
HISM: Hierarchical Instanced Static Meshes
support for LODs (e.G. Foliage) per object
If you have some weird errors you may not know how to fix: with UE5.6, you always have to explicitly include everything needed. Where before it sometimes worked without it, it just won't any longer. And then that should fix almost all other issues as well.