1 Challenge 1: Skin weight painting

One of the most common and tedious challenges of facial rigging with joints and controllers is skin weight painting. This is the process of assigning how much each joint influences each vertex of the mesh, and it requires a lot of manual tweaking and testing to achieve a smooth and natural deformation. If the skin weights are not painted correctly, you may encounter issues such as unwanted stretching, collapsing, or clipping of the mesh.

2 Solution 1: Use tools and scripts

To make skin weight painting easier and faster, you can use various tools and scripts that automate or simplify some of the tasks. For example, you can use the Paint Skin Weights Tool in Maya to paint the weights interactively, or use the Mirror Skin Weights option to copy the weights from one side of the face to the other. You can also use scripts such as ngSkinTools or Comet Joint Orient to create layers, blend modes, and masks for skin weights, or to fix the joint orientation and alignment.

3 Challenge 2: Joint placement and naming

Another challenge of facial rigging with joints and controllers is joint placement and naming. You need to place the joints strategically and precisely to match the anatomy and topology of the face, and to allow for a wide range of facial expressions. You also need to name the joints consistently and clearly, so that you can easily identify and select them later.

4 Solution 2: Use guides and templates

To help you with joint placement and naming, you can use guides and templates that provide a reference for the optimal position and orientation of the joints. For example, you can use the Face Machine or the Advanced Skeleton plug-ins in Maya to create a facial rig based on a predefined template, or you can use the Rapid Rig or the Face Rig Generator scripts to generate a custom facial rig based on your own guides. You can also use the Rename tool or the Search and Replace option in Maya to rename the joints in bulk.

5 Challenge 3: Controller setup and animation

The final challenge of facial rigging with joints and controllers is controller setup and animation. You need to create controllers that are intuitive and user-friendly, and that allow you to control the joints and the mesh with ease and flexibility. You also need to animate the controllers to create believable and appealing facial expressions, and to sync them with the voice and the body motion.

6 Solution 3: Use constraints and drivers

To improve your controller setup and animation, you can use constraints and drivers that link the controllers to the joints and the mesh, and that automate or simplify some of the movements. For example, you can use parent, point, orient, or aim constraints in Maya to attach the controllers to the joints, or to make them follow or point at other objects. You can also use drivers such as set-driven keys, expressions, or utility nodes in Maya to create relationships between the controllers, such as making one controller drive another, or creating sliders or switches for different facial poses.