Adding Terrain holes

A limitation of terrains is that they are a single mesh, with points raised or lowered. Sometimes, we want more complex, concave geometry for effects such as caves, tunnels, or just simple holes in the terrain. In this recipe, we'll build on the previous one to add a Terrain hole that leads to another piece of terrain:

Figure 5.46 – A third-person controller character falling down our Terrain hole to a bonus level