How to reduce difference between Path Tracing and Ray Tracing renders

Hi everyone, I’ve been working on rendering a couple of scenes but I have a lot of problems making Ray Traced render look correct compared to Path Traced ground truth. I’ve even been tempted to use Path Tracer rendering but due to the limitations of Path Tracer, I don’t think that would be possible.

Im using UE 4.27.2 with following settings:
r.RayTracing 1
r.RayTracing.GlobalIllumination 1
r.RayTracing.GlobalIllumination.MaxBounces 2
r.RayTracing.GlobalIllumination.SamplesPerPixel 16
r.RayTracing.GlobalIllumination.EvalSkyLight 1
r.RayTracing.AmbientOcclusion 1
r.RayTracing.AmbientOcclusion.SamplesPerPixel 2
r.RayTracing.Reflections.MaxRoughness 1
r.RayTracing.Reflections.MaxBounces 2
r.RayTracing.Reflections.Shadows 2
r.RayTracing.Reflections.ReflectionCaptures 1
r.RayTracing.Reflections.Hybrid 1
r.RayTracing.Reflections.RayTraceSkyLightContribution 1
r.DepthOfFieldQuality 4
r.BloomQuality 5
r.Tonemapper.Quality 5

Directional Light and Sky Light are set to work with Ray Tracing. Scene looks fairly good, but I’m quite bothered by how dark the wall is. It seems to be mostly caused by Sky Light contribution, as it makes the wall (and the whole scene) substantially brighter but also looks much worse and very wrong. I feel like I’ve tried everything and failed, so any help is greatly appreciated. Thanks, IK


well, I don’t think is possible to get not even similar quality…

What about to add a light channel 1 or 2 just for the wall?


as you can see point light is just affecting the rock

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Hi Alberto, I was somewhat afraid that might be true. Funny enough, I came across that same video just a few minutes ago.

I like the suggestion for 2nd light channel, it might get me just enough light to make the scene appear somewhat right. Ill try that and will post results :slight_smile:

Yeah is normal, path tracing is for the final render

To have multiple light channels is the way,
just keep in the wall also the channel 0 and add the 1
and new light only channel 1

let me know!

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Thanks Alberto, I’ve tried as suggested, and it’s looking considerably better. Do you have maybe any other suggestions or tricks to improve the rendering quality? PathTracer render still looks more “crisp”.

sure, in the console, when you want to have a better preview, execute:

image

r.ScreenPercentage 150
r.TemporalAA.Upsampling 0
r.ForceLOD 0
r.Tonemapper.Sharpen 1
r.TextureStreaming 0

and of course!