Technical Journal on Rigging (Week 4)

Continuing from last week, my explorations will be revolving around Eyad Hussein's Advanced Rigging.

Summer 2013 Review – Advanced Rigging - Eyad Hussein 

And this week, I have started to apply the joint based rigging:

Placement of the joints

Basically, after positioning the joints, the model is ready to be skinned. There are some tips on positioning joints and skinning:

1. Joints are used to influence vertices in skinning, so have in mind which vertices are going to be affected when you place your joints. (Don't place unnecessary joints, unless they are used for something else.) 

2. The movement of the joints can vary from rotation to translation. (depending on the desired deformation)

3. Your topology affects the placement of the joints. (As stated in 1)

In this case, I haven't explored the whole range of joint based facial rigging yet. But here is some lips movements I experimented with joints.

I made a smile and a frown, but they still look so raw. 

I hid the joints because it's unclear and messy in the screenshot. But the deal is, when we usually use Blendshapes to do our facial expressions and deformations, here we are only using joints influences to reach the desirable result. Blendshapes are only used for extra range of movements (for the lips) and final touch, which uses the similar method of Corrective Blendshapes. (It activates when the controller reach certain point of translation or rotation.)

In the end, this week I found that this method of Facial Rigging is using a different workflow (or pipeline) than the Blendshapes Facial Rigging, because its deformations have a more detailed control from the joints. It also gives a better in-betweens for change of emotions.

And furthermore, this kind of facial rigging can still be combined with Blendshapes, because the joints are affecting the mesh on a different layer. 

However, I think this method should be done only when a lot of details are focused on the face of the character. The heavy use of SDK might also affect the usage of the rig.

Pros of Joint Based Facial Rigging:
Better control of facial features
Better inbetweens from a facial expression to another
Higher Flexibility in Animating
Easier Animation Tweaks
Able to deform with more mathematical control (using translate / rotate to slide the vertices, scale to expand the volume)

Pros of Facial Blendshapes:
Quicker to set up, easily editable
Faster for productions when the rig doesn't necessarily need to do every facial movement
Lighter to calculate
Possible to setup extreme deformations purely by sculpting (some of which joints can't do)

Both are still advised to use Corrective Blendshapes to polish up the outcome.