Follow slope and bumps while lerping

I was wondering how I could get an actor to lerp across a plane which may slope down (hills) or have bumps (like sand dunes). How can I do this?

Trace in the direction you’re moving and downwards to see what’s ahead. Do that more than once for more accuracy. You’ll end up with a series of coords defining the curvature of the terrain. You can derive an average from this.

How do games like tony hawk pro skater handle this type of stuff?