When character rig is generated, these prototype objects are used to create point and box controllers, as well as rigid bodies needed for animating the character and making its movement physically accurate.
To rig a character, you need to add a set of prototype objects to every joint of the character skeleton.
Prototype objects are created in sets. Each set includes:
1. Proto rigid body
The main element of the set. A proto rigid body is attached to the joint (or several joints) and holds all the other objects.
When the rig is generated, a proto rigid body is used for creating a rigid body.
2. Proto box controller
The secondary element that encompasses the joint(s)
When the rig is generated, this object is used for creating a box controller.
Proto point controllers
These three elements are used for creating point controllers when the rig is generated.
3. Main point controller
Placed at the foundation of the main joint. Prototypes for Point Controller Edges connect it to two more point controllers
4. Main direction point controller
Placed at the point where the main joint connects with the child joint. Its position is determined by the child joint
5. Additional point controller
Its position can be set manually using the Additional point in Axis group of parameters
You can also use Manipulators to adjust the positions and sizes of the prototype elements; this is not required, but can be useful in some cases.