The PN-Triangles and Gregory ACC samples each show how to determine scaling factors, offset tessellated vertices using interpolated positions and normals, and avoid gaps at seams.

The last two samples demonstrate everything you need to know to extend tessellation technology to artist-generated content. Meanwhile, the Terrain Tessellation sample takes this a step further, demonstrating how this can be applied to a massive streaming dataset, dynamically loading new terrain sections and showing how to adjust tessellation factors so that T-junctions aren't visible at the seams. The Island sample demonstrates how tessllation can be used for objects like terrain and water, deriving the desired tessellation level from the camera position and using texture data to generate geometry at the desired detail level on the fly. Tessellation is a natural solution for geometry that is largely data-derived and where the players view may vary widely within a scene.

The first sample pictured above, Tessellation Pattern Viewer, provides a simple visual explanation of how the subdivision is controlled, as well as examples of the various modes that DirectX 11 tessellation can run in. For those not familiar, DirectX 11 adds several stages to the geometry pipeline, which allow new classes of shaders to determine if and how each polygon produced by the Vertex Shader should be subdivided the GPU generates the desired mesh accordingly, and then then, a second shader runs on the resulting geometry so that it can be manipulated as the programmer sees fit.

The first major DirectX 11 feature that the SDK covers is hardware-accellerated tessellation.

Nvidia directx 11 download