Seeing the Tessellation Levels

You can see the difference in the following figures:

Figure 9.2. A very low-detail sphere.

As you can see here, this "sphere" doesn't look much like a sphere. Hardly any triangles are being drawn, it looks all blocky in solid fill modes, and it's just not very realistic. However, if we just split each triangle into multiple triangles (subdivide) a few times, it looks much better.

Figure 9.3. Adding detail to the sphere.

The sphere looks much more like a sphere now than it did before. Each triangle has been tessellated quite a few times, and the effect makes the sphere look much more realistic.

Figure 9.4. The normal detail of the tiger.

You can see how the tiger looks somewhat blocky, although the texture definitely helps hide some of this. However, it's still obvious if you're looking for it. Increasing the tessellation will remove this blockiness.

Figure 9.5. A very highly detailed tiger.

With the increased tessellation, you can see that the blockiness has disappeared.