14 In the Top viewport, rotate the car until the front bumper is pointing to
the left.
15 Save your file as mycar_rig_03.max.
Rotate the wheels (under a path constraint):
In the previous procedure, you learned how to add controllers that rotate the
car wheels for any distance of travel in World X and Y space. The wheels will
therefore rotate properly when you manually move the car around the scene
in any direction.
However, you would most often animate motion of a car by placing it on a
pre-defined path using Path Constraint. This type of animation requires a
different expression.
This new expression uses the same formula (distance divided by radius) as the
ones you have been using, but while the radius of the wheel remains constant,
the distance travelled is calculated differently.
1 Continue from the last procedure or open the file car_rig_03.max.
2 From the main menu Selection Sets list, choose Car Path.
A warning message displays.
3 Click Yes to display the path you will use to animate the car motion.
4 From the main menu, choose Create > Helpers > Point.
5 On the Parameters rollout, turn on Box and set Size to 100.0.
626 | Chapter 4 Animation Tutorials
