Installation:

Unzip the file into C:\Ubisoft\Watch Dogs Legion\data_win64\

Update the above with the directory where the game is installed

Click overwrite if prompted. This will replace the pre-existing
patch_english.dat and patch_english.fat files

I have not encountered any issues with language/subtitles up to this point by replacing these files.

To activate ray tracing parameters you need to select the 'medium' preset from the Ray Tracing option in Video/Graphics settings in game.

This mod updates the Medium Ray Tracing preset on PC to use the Xbox Series S ray tracing settings. These settings have been extracted from the patch.dat file which includes a folder path:

> engine > settings > defaultrenderconfig.xml

The medium present was swapped out for the Xbox Series S settings found here:

Enable="1"
QualityLevelIndex="4"
RoughnessThreshold0="0.0625"
RoughnessThreshold1="0.075"
UseCompressedFormat="1"
StaticInstancesBvhRadius="96"
DynamicInstancesBvhRadius="32"
ClustersBvhRadius="96"
BuildingsBvhRadius="96"
TerrainBvhRadius="96"
RoadsBvhRadius="96"
VegetationBvhRadius="96"
ParticlesBvhRadius="32"
BoundingRadiusThreshold="0.25"
EnableWaterTiles="1"
EnableParticles="0"
EnableProjectedDecals="0"
LitterAndGrassRadiusRatio="0.25"
AlphaTestedGrassRadiusRatio="0.4"
GrassDensity="0.6"
RoadDecalsSizeThreshold="1.3"
DecalsAllowAnyNbrQuadsOfQuads="0"
RoadDecalsMaxNbrQuads="4"
DisableTeethGeom="1"
AngularSizeThreshold="2.0"
LightMaxNeighborCellCount="4"
MaxProcessedLightCountPerFrame="2048"
DenoiserType="1"
CheckerboardMode="2"
NrdEnableBicubicFiltering="0"
RayLengthMin="2.0"
RayLengthMax="96.0"
RayLengthDecay="20.0"
SSRStepRate="20"
SSRMaxSteps="32"
TraceResolutionX="1280"
TraceResolutionY="720"


This file replaces a separate smaller patch file: patch_english.dat & patch_english.fat - the reason for this is because these files are significantly smaller than the main patch file which has grown considerably since release and includes all new patches since the games release.

Why use Xbox Series S? - as the lowest specc'ed console with Ray tracing enabled, this offers a lower than medium preset for PC users, and allows us with medium/low performing GPUs to still apply ray tracing and enjoy the improved reflective qualities it offers.

Why not offer PS5 and Xbox Series X ray tracing configs? I might do this in due course if there's general interest in the mod.

If you want to support my efforts please consider donating at: paypal.me/RobSMods2021


Thanks go to digital foundry for covering the original settings across the consoles. This galvanised me to attempt this mod in the first place.
Additional thanks go to the members of XeNTax game research forum for the tools as well as advise from the members including but not limited to:
superdemus
Combragamer

And final thanks go to the tool creator: rootCBR
https://github.com/rootCBR