(HELP) How to create custom ground models?

Help guys!! I do not know where the file that have the ground models. I tried looking to other forums but it's outdated.
And the groundmodel.lua file no longer exist.
If you can help, thanks alot

 

Maybe it was deprecated. Im not exactly sure, though.

EDIT

Never mind. I forgot what the groundmodel was. Its the ground collision. Ive never messed around with the terrain collisiond so i dont know.

 

Nadeox1 posted an exemple here : Groundmodel Properties?
Hope it helps.

 

thanks