Hardware Tessellation

Displacement mapping makes a wall look deep, but the wall itself stays flat, and so do its edges.

With hardware tessellation the graphics card splits a wall into many small faces and moves them in and out according to the texture's height map, so the wall really bulges. D2X-XL does this for rock, water and lava; doors and the technical parts of a level stay flat.

Walls that meet at an edge or a corner stay connected, so no gaps open between them, and an edge shared with a flat wall remains straight.

The amount of detail follows the distance: walls close to you are divided finely, distant ones coarsely.

Hardware tessellation is active with render quality set to high and lighting quality set to high or extreme. In expert mode the render options offer two sliders for it, relief wavelength and relief height; both take effect in the running game.