Json files are in D2R\Data\hd\env\vis\
and can be extracted with CascView
There are 6 outdoor jsons:
act1_outdoors_dawn1.json
act1_outdoors_dawn2.json
act1_outdoors_day.json
act1_outdoors_dusk1.json
act1_outdoors_dusk2.json
act1_outdoors_night.json
Setting the depthFogColor to 1,1,1 and depthFogDensity to 0 will remove the fog effect in act1
"depthFogColor": {"x": 1, "y": 1, "z": 1},
"depthFogDensity": 0,
Launch your game with -direct -txt
I first noticed how fog was not present when I entered a hut in act1's wilderness. The grass looked greener and I wanted to remove the grayness from my outdoor areas.
With this json edit the grass and environment looks more vivid and less gray.