Add this line to ROADS in your .tdf file: Overwrite the old data.
Reaction=spray Tex=rainspray.tga Max=1024 Scale=(0.4,0.06,0.7) Growth=(0.4,0.4,0.8) GrowthVel=(0.08,0.1,0.35) Power=0.41 RampSpeed=80.0 OffsetVel=0.10 ASDEnvelope=(0.05,0.07,0.90) DestBlend=InvSrcAlpha SrcBlend=SrcAlpha
This is very nice rainspray.
In your .plr file you can set whether the spray comes from only the rear tires or also the front.
I believe "Flows over vehicle" is for the front tires spray to flow over the car.
For raindrops put this in "Other loose special effects". Down at the bottom of the .tdf
Reaction=rain Tex=raindrop.tga Max=4096 Scale=(0.5,0.5,0.3) Particle=Plane+Deformable DestBlend=InvSrcAlpha SrcBlend=SrcAlpha
I added a custom made raindrop that I use on my sim.
You must rename the .txt file to .tga for it to work.
I had to name it .txt to upload it here.