Rigging a Car 2

  The next thing was to start creating suspension. I did this using the main car group I had made (Truck_Grp) and setting appropriate pivot points. The heir-achy I created went as follows: the main body (Truck_Body_Grp) inside the rear suspension group (Body_Rear_Sus_Grp) inside the front suspension group (Body_Front_Sus_Grp) finally inside the main body group (Body). With the outliner set up ready I created controllers for the different parts. I created two downward pointing arrows, one at the front and one at the back to control how they went up and down. The pivot points for these arrows had to be on the opposite side of the car. For example, the Rear suspension arrow pivot needed to be in line with the front wheel axles. After doing this I created an expression that enabled me to move the arrows up or down to move the suspension on the pivot. Here is the expression I used for one of my controllers:                                Body_Front_Sus_Grp.rotateX = Rear_Ctrl.translateY;

The next controller I created was the main suspension control. This is used to move the whole body around one pivot point (would be used when animating a car over rough terrain or turning corners. I created the controller, once again, using NURBS in a shape which matched the movement so it was clear to understand. I then created a pivot point in the appropriate body group of the car that was in the middle of the whole body. I then constrained the controller to the group, thus creating a control that could be used to move the entire body. 

  As I did with the wheels I colour coded the controls (In this case, red for suspension) and created limits so as not to break my model. I made sure to limit the movements so I could only move what I wanted to be moved. for example, I didnt want people to be able to rotate and scale controls that weren't meant to be scaled or rotated. To solved this, I created limits so you couldn't scale or rotate these particular controls at all, and you could only move them where I had set limits to and from. 

  To finish off the car, I created a main control. This I made by creating a square on the floor of the vehicle once again using NURBS. I constrained this to the whole car as a group so I could move the entire car around using this square. I also created a global control. This created to give the car an original position. by moving my main control around to move the car, the global control stays exactly where it started. This is useful when animating a scene. Because everything in outliner is beneath the global control in the heir-achy  this means wherever the car goes the controls follow with it.