Lesson 1 - Parenting and Groups

What is Rigging?

Rigging is a process of attaching bones and joints to a mesh which are further connected to controllers which the animator then uses. It is much like pulling the strings of a puppet. Influence is then assigned to the bones and joints so that certain bones manipulate only the vertices around its envelope.

There are two commons methods of controlling a skeleton, inverse or forward kinematics. Inverse makes the bones follow a target while forward is individually rotating the joints to achieve the desired effect.

Parenting or Grouping?

There are two main types of joining objects together, parenting and grouping. Parenting sees one object act as a 'parent' and the other attached to it are known as a 'child'. If the parent is manipulated then the child will copy its manipulation. Below is an example of two spheres, the left is the parent.

In the outliner you can see that the middle and right spheres are parented to the left sphere...

If I manipulate the left sphere (the parent), the other spheres (the child), will copy it. In this case I changed the rotation and scale of the parent...

 

However, if I manipulate the child independently, the parent will not react...

If I move the parent again, the child will still copy despite its changes.

Grouping is more versatile than parenting. It acts as a 'null object parent' (essentially, a non existant object is the parent). More so, a group of objects have their own independant pivots as well as a group pivot while parenting only has the objects pivot.

It's possible to have more than one group for the same objects. This means we can have multiple pivots for the same set of objects which can be useful for joints such as a foot (Heel pivot, ball pivot, toe pivot). All the objects will move based on its groups pivot.