I have been trying scripting these past few weeks, and its fun!
There is one thing I want to do though and that is to randomize the color of terrain!
When I try to use this code:
local ter = game.Workspace.Terrain
ter.Material.Grass = Color3.fromRGB(math.random(1,255), math.random(1,255), math.random(1,255))
It doesn’t work.
I did this with WaterColor, and it worked fine. Is there a reason it doesn’t work?
Thanks and have a nice day 
i am no think that there is any way to script the roblox terrain well maybe you can script just the water and thats all beacuse i tried script water terrain and is works after that i tried script the grass color and that no works for me. anyway i am think that there is no way to script the roblox grass.
There no script for change colour for terrain , if you want change colour terrain so :
you can change terrain but only the water by script.
Water can make with script or can change water on terrain !
is what i said but like if you want make a local script and make part that when player touch the part so is change the water so you can.
also i am think that there is a way to script terrain on roblox like grass beacuse i found game that doing that: 💰 x20 MONEY 💰 🍃 LAWN MOWING SIMULATOR ⚡ - Roblox
Well is mean water can’t recieve shadow of picture on water for example the picture here :
So where i can change water it ?
here
and also make sure that the lighting is shadow-map (for give the shadow effect)
Well… i just got shadow !
and thats what you want right? 
Yes that i want they about this !
change the graphics and you will get the image
