Another interesting thing you can do with Smart Car is define zones in the level to either cause the car to brake and slow down or adjust the friction of the car to make it drift. These are similar to the vector fields we saw in Chapter 5, Crowd Control, where we place them in the level to affect the AI, and they aren't visible to the player but are good to use for scripting level experiences. To create a brake or drift zone in your game, add a cube to the game (go to GameObject | Create Other | Cube) and scale and translate the area you want to tag in the level. In the Inspector window for the cube, set its tag to BrakeZone and for a drift zone set the tag to DriftZone. Next, in Box Collider for the cube, check Is Trigger to true, so the car will get a message of intersecting with a cube but won't stop and collide with it. Lastly, in the Inspector window, uncheck Mesh Renderer so that the cube is invisible in the game. Now when you run the demo, if the car's speed is 25 or over when it enters the brake zone, you will see it slow down, and if its speed is 15 or over, you will see it drift in the drift zone.

In this demo, we've seen that setting up an AI car that drives around is easy to do with Smart Car. However, what if your game isn't just a driving game but has car driving as one part of the game? If that's the case, you can mix Smart Car with another AI system easily. For RAIN integration, import the RAIN package into your scene. Then, go to RAIN | Create Entity and then select Add Aspect: Visual Aspects. This creates an entity with an aspect that can be sensed by additional RAIN AI entities you can create in the scene, making the car just one part of a larger AI system.