https://player.vimeo.com/video/655326344?h=f36e130479&badge=0&autopause=0&player_id=0&app_id=58479
Without tfFold on the left and on the right tfFold is active.
There are two Mode settings: Fold Top, or Fold Bottom.
The Mode setting on the left is Fold Top. On the right, it is set to Fold Bottom.
Heightfield values that are above the Level setting will be folded down.