I have a game that I want to create a tilted plane in.

I need a way to make a smooth plane on a fixed 25 degree rotation. can this be done?

Long story short my game is a downhill game and the player is being controlled by gravity. I have already made a few very successful level planes and tweaked gravity and just gave the illusion of going downhill however I am at a point now where If I want to turn 90 degrees while going down the hill it cant be done the way i have it setup. I thought of making multiple smaller terrains and snapping them together or making 1 larger terrain.

I tried using heightmaps to generate the terrain but it turns into almost a staircase effect.

I tried using a script to generate the terrain but i cant get a terraindata to generate with it and only a box collider would work. I am still new to unity so any help would be greatly appreciated!

Why not just rotate it in the inspector?