I got path tracing to work on my 1080 ti with UE5 early access by adding “r.D3D12.DXR.AllowEmulatedRayTracing=1” into my DefaultEngine.ini. Unfortunately, Epic removed this console variable in UE5 Preview which deprecates ray tracing (and therefore path tracing) for all GTX 10 series cards. I found a very hacky workaround which is very annoying to setup, but works well enough until Epic addresses this issue.
- This method involves building UE5 from source, so follow the steps needed to gain access to UE5’s source code. (Downloading Unreal Engine Source Code | Unreal Engine Documentation)
- After installing the source code on your comp, navigate to this file from the root directory of the source code: Engine/Source/Runtime/D3D12RHI/Private/Windows/WindowsD3D12Device.cpp
- Open the file, and change the line that says:
#define DXR_ALLOW_EMULATED_RAYTRACING 0
to
#define DXR_ALLOW_EMULATED_RAYTRACING 1
This will allow you to access this cvar from withing UE5 Preview. - Compile the source code, and you’re done! You should be able to set this cvar from within the custom built UE5