Here, I will introduce a demo program (demo_C) that animates a human body model walking. The model is Akira, a Virtua Fighter. Akira consists of 22 polygon objects, each of which has a hierarchical structure as shown in the figure below.
Figure C-1 Akira's parent-child structure
Note) Akira is now facing you.
By having angle data between each parent and child object of Akira, you can create a "joint". By changing this angle data, you can move Akira connected by joints. The angle data between each parent and child object is called "motion data".
Complex motion data such as the human body is usually created with a 3D animation tool or the like.