Introduction to Rigging

Rigging is the process of creating a system that allows for appropriate deformation of 3D models for animation purposes. The term rigging is a very general term that covers a wide range of skills necessary for the setting up of a character/prop for animation. A character rig is a system of controls that allow an animator to manipulate and pose a character without having to deal with the often complex construction and composition of a character’s mesh, skeleton and other systems used to deform the mesh.

There are essentially three stages to successful character rigging:

1) Character modelling (with the requirements of rigging in mind)
2) Deformation setups
3) Controller setups

Note: a rig doesn’t necessarily involve deformations. Eg. A rig can be used to animate the various parts of a car.

The result of a good character rig is… Ease in animation.

A good rig is an unbreakable rig… but experience shows that animators in moments of frustration can and will break your rig.

The task of rigging for prop, characters and special FX is the role of the Technical Director. The simpler a rig is to use is often inversely proportional to the complexity of rig setup.

Your first rig will always be your most frustrating and difficult to animate. Gradually as your rig improves you will see that your animation will also improve.

Script Analysis for rigging

Before even considering the particularities of a rigging setup it is essential to scrutinise your script/storyboard and analyse all the kinds of movements your characters/props will make during the course of the story.

It is a fruitless exercise to try and create a rig that can achieve all conceivable poses.

For a scene/story you should sit down and list the nature of all movements. Your non-dialog narrative should give you a starting point for this analysis.

Having a list of required movements for each character delimits the rigging task, laying out all of the rigging challenges.

Modelling for rigging

As a central part of rigging requires the realistic deformation of your character’s mesh it is important to understand how your character will move before you start the modelling process.

Deformation usually requires the stretching or twisting of certain areas of your mesh.

In the analysis of character movements you need to think about which parts of the mesh will have to stretch in order to attain a certain movement or posture

For example:

1) For an arm to bend the skin around the elbow has to stretch BUT the skin between the shoulder and elbow does not have to stretch.
2) For petals to blow in the wind, the tips of the petals may have to wobble a lot, but the base of the petals will stay rigidly attached to the flower.

The implications in terms of modelling are in the resolution of your mesh. Rule of thumb: create detail where it is needed for a smooth deformation, if the region doesn’t deform, make the geometry lighter.

In the end it is desirable to have a responsive rig. If the rig is too heavy then you will be spending all of your animating time waiting for screen refreshes.

Character Mean

This is the default pose of the character. This is derived from taking the two greatest angles a joint will bend to in both directions, and setting the default position of the limb halfway between the two.

So when you are creating your Visual Style Guide and character models, make sure you have your characters in a pose that satisfies the character mean based on your analysis of character movements in the script.

Typically people would model bipeds in the traditional T form or Jesus position, but your character model sheets should take into consideration the limits of movement.

This helps reduce ugly deformations.
Introduction to Skeletons

The Joint Tool

We will begin with the legs, press F2 if you are not already in animation mode, and then select SKELETON > JOINT TOOL

In the Layers Menu, set your Character_Mesh to T for Templated. Although we may have modelled both sides of the body, the joints are symmetrical so we only create one half and then we mirror the joints across to the other side, we will be using the character's right side as your looking at him when setting up the joints to be mirrored. In your side view, draw the following joint chain : - Joint Naming As you create more and more joints, your scene will become increasingly complex and difficult to understand, so it is important to start giving every joint you create a meaningful name within it hierarchy Switch to the front view, as this is where we will be placing our joints for the arm, and without any snapping turned on, create the following joints for the arm, don't worry too much about placement right now, just so long as it roughly matches this diagram

Front View

Within your Outliner, rename the joints, starting from the first one, like this

Make sure that the elbow of the arm bends outwards