Overview of the Tuning and Sculpting Process
Face Robot addresses many of the difficult technical challenges of facial animation through an elegant abstraction of facial anatomy and a model of how the soft tissue of the face deforms. It allows you to work with many aspects of facial deformation including cheek bulging, nose flaring, lip curling, and wrinkled skin.
Regional face deformers are key elements of the soft tissue model, which is an underlying concept of Face Robot. These deformers correspond roughly to the different muscle groups of the face. They deform different areas of the face to simulate tissue compression, such as the way a cheek creases with a smile, or the way a cheek puffs from inflating the inside of the mouth. The deformers interact with modeled and weight-painted wrinkles and folds on the mesh.
The tuning stage is nonlinear, and the order in which you do things depends largely on personal taste and workflow. You can use any process you like in Face Robot to achieve the results you need: painting weights, sculpting, region deformers, or shape animation. You will probably need to adjust the deformation as the animation goes along. Face Robot makes it easy to go back and forth between the Act and Tune panels as you like to continually refine your work.
To help you realize the range of expressions you need to accommodate with the face, make sure that you have an array of reference materials to verify the accuracy of the soft tissue model. These materials can include motion capture data that indicates range-of-motion, as well as digital photographs, high-resolution 3D scans, clay maquettes, or concept sketches of the facial expressions you want your character to achieve.
To get started with tuning, you can use the following steps as a general guide to getting the face into good shape:
1. In the modeling stages, make sure that the face’s topology works well for mouth deformation and for wrinkling — see Modeling the Head for more information.
2. On the Stage 5: Act panel, move the animation controls around to see how the face is deforming. Generally, you want to hit the “big ticket” items first: make sure the mouth is working as you expect, and check that the jaw is also moving properly.
If your landmark picking or fitting was way off here, you may need to solve the head again before you do any work in the tuning department.
3. Do any major re-enveloping that might be needed (back of head, ears, neck, etc.) — see Adjusting Envelope Weights. You cannot adjust envelope weighting on the mouth area.
4. Fix up any issue with the points in the mouth region cluster and regenerate the mouth if necessary to make sure that the mouth is deforming properly — see Fixing Problems and Regenerating the Mouth.
5. Paint a basic wrinkle map of the mouth, eyes, and eyebrow/forehead areas — see Painting Wrinkle Maps.
6. Paint a basic puff map that affects the cheek puffing deformers — see Painting Cheek Puff Maps.
7. Now you can work on the face, region by region, to tune each region deformer’s range and strength (see Working with the Region Deform Areas) according to the animation, and to adjust the region map through painting.
- Starting from the forehead and moving down the face is one way to keep track of the facial area you’re working on.
- The general workflow when tuning the forehead and neck or cheeks is to start with painting: this allows you to define how big or small each muscle region is, as well as the relative amplitude of the muscle.
8. The skin sculpting is useful for more finely detailed shaping once the overall muscle area is behaving properly.
Move the animation controls around in each region of the face, or move them into an extreme pose (such as moving the mouth corners in a smile position). Then sculpt that region to have the optimum amount of deformation for each pose, one area at a time. See Overview of Sculpting for information.
- For specific tissue deformation effects, especially around the mouth (such as enhancing an “ooh” shape), you can use the standard shape animation tools on top of the mouth sculpting.
- Fine-tune the painting on the wrinkle map and puff map as you sculpt.
9. Adjust the eye curves and maps for blinking - see Tuning the Eyelids.
10. Set up the mouth’s collision and other mouth parameters to adjust the mouth to your liking - see Tuning the Lips and Mouth.
If things seems to be getting sluggish as you model shape fixes and tune the face, click the Freeze button on the main command panel. This collapses the stack and the history of all of your tweaks, but speeds things up considerably.
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