Old_2013/tutorirls & Tips2008. 8. 22. 10:54
This rig was created for the 4th DVD in the Intermediate Rigging Series from CG Academy. Two rigs were created for the DVD, the first is a blended morph driven system with a floating UI loosely based on the system outlined in the book Stop Staring by Jason Osipa.

Morph based system
Bone based system
Render of bone based system

Fifty bones were used to control the major muscle groups of the face to allow for a limitless range of motion.

The bones are controlled by two sets of controls, course and fine. The course set controls the fine as well as control each other so when the corner of the mouth is moved the cheek and other areas will move as well. This set up is circular and the controls that the corner of the mouth moved can also move the corner of the mouth. Once an over all pose is created the fine set of controls can be used to tweak shape.

The facial rig is also repurposed easily into other characters.

A screen grab of the rig reveals all the helper objects that have been used. Although this looks complex each has its purpose and is fairly simple to set up.

In the DVD I cover all the steps that are needed to recreate this rig in the Ogre character or any other type of character. Many scripted solutions are also used to speed up the process and automate some of the steps that are repeated over and over.

This is an unconstrained setup that is best used for characters were you want a very large range of motion. The animator has the ability to shape the face on any axis without reaching limits of morph targets or predefined shapes.

The main difficulty with with bone based systems is achieving realistic skin weights on the fifty bones.

Often bones need to be added to hold areas of the skin in place so that the skin doesn't deform to much.

Skin Tools has some excelent tools for blending weights together as there can be many bones affecting any one vertex. In places in this character there are up to 8 to 10 bones affect a vertex.

This is an image of the UI and character for the blended morph system. This system uses a series of morph targets and blend targets to achieve facial poses by bending many targets together at once. The control interface allows for easy control over the face with a floating UI system. There is also a pose capture system hooked up to this rig using the PEN Attribute Holder modifier found in the scripts section of this site. This method was also outlined in the book Stop Staring by Jason Osipa but is done in Maya instead of max.

Various images that were used for the promotion of the facial rigging DVD from CG Academy

Posted by dhkim DongHwan, Kim

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