DX 11 Tessellation off
DX 11 Tessellation off - wireframe mode
DX 11 Tessellation on
DX 11 Tessellation on - wireframe mode
Let's focus on a few characteristics of tessellation in the first image. Firstly, when we compare the wireframe mode, it is clear that tessellation, triangular in this case, is adding a lot more features and details, which may at first not be recognisable. The surfaces are divided in many more triangles, allowing the objects to replicate more complex structures. The ground for example is one of the features that benefits from it. To make it as efficient as possible, tessellation becomes a function of distance, generating more polygons closer to the viewer.
Now let's look at the application of this. If we gaze at the rock pillar closest to us, we can immediately notice that with tessellation, they are not just mere square blocks but instead have irregular surfaces, more representative of a natural rock. Now, let's move on to the stairs, which again is a notable improvement on past rendering methods. Rather than being flat, they have depth, giving the impression of real steps as opposed to a slide. The same applies to the cobbled road although the compressed/downsized pictures make it hard to judge. The last thing I'll point out are the tiled roofs. With tessellation, the individual tiles form a more complex/realistic shape instead of appearing flat with repeated textures. You'll have to take my word for it if you don't notice them or try the demo for yourself!