Before we start with facial rigging, I would like to mention that we'll be discussing more on positioning the bones or rig on the face. I am going to skip the basics. The shared rigging system we used is still on progress. But I hope this will help you towards animating a human face. Visit the link to download the max file: http://www.4shared.com/file/hoP5YIIV/facial_rig_system_00.html
Let us start on facial muscle image. Facial muscles are like our 3d facial bones or rig. They are responsible for the pushing and pulling force on the face area that creates an expression. Muscles underlies our skin, and in 3d though we are not going to create rig or bone for every strand of muscles, familiarizing ourself with facial muscles will be a plus.
1. Let us begin working with the forehead. Set the Coordinate System to Local and freeze the head object. Select and position the bones and helpers similar to the image below. Do the same on the other side.
2. The Brow and Upper cheek Select and position the bones and helpers similar to the image below. Do the same on the other side.
3. The Eyelid Select and position the bones and helpers similar to the image below. Do the same on the other side. Anticipate how the corner bones are situated on the eyelid area.
4. Nose Select and position the bones and helpers similar to the image below.
5. Neck Select and position the bones and helpers similar to the image below. Do the same on the other side.
6. Jaw Select and position the bones and helpers similar to the image below. Do the same on the other side.
7. Mouth area Select and position the bones and helpers similar to the image below.
6. Cheek Select and position the bones and helpers similar to the image below. Do the same on the other side.
After we are done with the adjustment, we move on to the skinning. The process of skinning really takes time but there are some helpful tools available inside 3d Max that we can use.
Please visit this link on how to skin a character. Thank you!