The lesson begins with an explanation about objects that are dependent on one another.
The example of a door is a good one. A door that is mounted on hinges cannot move unless the hinges move as well. The movement of the door and the movement of the hinges are dependent on one another.
In the case of 3DS Max, we must decide on a hierarchical order for these objects. The text makes it easier by starting with a doorframe object, which is the parent of the hinge object. The hinge rotates with respect to the doorframe. The door can be made a child of the hinge object, since it rotates with respect to the hinge. (If it seems strange to think of a doorframe as a parent, think of the doorframes that moved on conveyors in Monsters, Inc.)
This order becomes important in 3DS Max: a child is linked to a parent. The movement of the child is dependent on the movement (or location) of the parent. The child inherits characteristics like movement from the parent.
The text reminds us that we have already learned to place objects in groups. Groups are not useful for movement in the way that hierarchies are useful.
Exercise Notes and Questions
Work through the exercises and turn in your answers to all questions below as part of the homework for this assignment.
Exercise 1: This exercise illustrates linking
objects in a hierarchy. It uses a button we have not clicked before,
the Select and Link button.
Exercise 2: Exercise 2 walks you through
creating a hierarchy with the Schematic View tool. Near the end
of exercise 2, you are told to look at the page and continue linking objects
as shown. The diagram is impossible to read. This is the series
I believe you should follow:
Exercise 3: This exercise has little value. We will skip it.
There is a brief lesson before exercise 4. It introduces two terms: Forward Kinematics (FK) and Inverse Kinematics (IK).
Exercise 4: This exercise does not explain the process of IK, but it has you use a file that has IK imposed on a (very basic) model of a human leg. Open the file and understand that moving the back section of the foot moves the calf and the thigh as well.
The text continues by describing features of the Hierarchy panel. Three buttons allow us to control three kinds of things:
Question 2: Where are the three buttons, on the hierarchy panel?
Exercise 5: This exercise examines hierarchy information about a railroad engine wheel. They are linked in a hierarchy, but there is an error in it.
Question 3: In step 8, you are told to turn
off Y axis rotation for the Pivot pin of the wheel assembly. Are we telling
it NOT to inherit rotation on the Y axis from its parent, or not to pass
Y axis rotation TO its parent?