Facial rigs are essential for bringing characters to life, allowing for realistic expressions and detailed performances.

Whether you’re diving into feature films, TV shows, or video games, knowing how to create and use facial rigs can make your characters truly stand out.

In this guide, I’ll walk you through the different types of facial rigs, their pros and cons, and give you practical tips on designing and building rigs that fit your project perfectly.

Define Your Needs First

Define Your Needs First
Define Your Needs First

When starting a facial rig project, the first step is to define the needs based on the type of project. 

For instance, 

  • If the project is a game, high-quality visuals are crucial, but detailed facial animations aren’t a priority. 

In such a game, the focus is on speed to prevent lag, given the high number of players and intense action scenes. Facial animations may be more detailed in cutscenes, but during gameplay, they remain minimal to ensure smooth performance.

  • Conversely, in a first-person boxing game for high-end PCs, strong facial work is essential. 

The game demands detailed animations that reflect the impact of punches, with facial distortions and sweat effects enhancing the realism. Although characters might not speak, the rig needs to support complex expressions and reactions.

  • For a children’s TV series, the rigging requirements differ again. 

Here, the priority is simplicity and speed to meet tight deadlines. Overly complex rigs with numerous controls can hinder animators, making it challenging to deliver on time.

Instead, a straightforward rig that allows quick and effective creation of major phonemes and emotions is preferred.

  • In contrast, a high-budget feature film demands the utmost realism and flexibility. 

Complex rigs that can handle intricate muscle movements and subtle facial expressions are necessary. However, such projects usually involve experienced professionals who are well-versed in creating these advanced systems.

Before beginning, it’s crucial to review the storyboards and script and consult with the animation team to understand their specific needs. This helps in tailoring the rig to the project’s requirements, ensuring it is neither over-engineered nor under-equipped.

Speaking with a senior animator can provide clarity, preventing the project from being bogged down by conflicting inputs.

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Top Options of Facial Rigs

  • Absolute Targets

Absolute Targets
Absolute Targets

Absolute targets in facial rigging are a common starting point for many technical artists (TAs).

This method involves creating a copy of the character’s mesh and modeling it into specific expressions, such as a smile, which are then added as Morph Targets or Blend Shapes.

This approach is straightforward and quick to implement, making it an appealing choice for simple projects or scenes with limited facial animation needs.

One significant advantage of absolute targets is their ability to capture fine details in facial expressions.

Since the target shapes are modeled directly, it’s easier to achieve subtle nuances like wrinkles and small muscle movements that would require numerous bones in a bone-based system.

This makes absolute targets particularly useful for high-fidelity facial animations where fine details are crucial.

However, absolute targets come with notable drawbacks. One major limitation is the rigidity of the expressions. Every time an expression like a smile is needed, it will look the same, lacking variability and flexibility.

Animators are limited in how they can transition into and out of these expressions, as the targets represent fixed poses. This can be a problem in productions requiring diverse and dynamic facial animations.

In the context of games, absolute targets can also be slower to process compared to bone-based systems. While they provide higher fidelity, this comes at the cost of performance, which is a critical factor in fast-paced gaming environments.

For example, in a game like Battlefield, absolute targets might be suitable for quick, predefined facial expressions during brief cutscenes or character interactions. However, their use in gameplay might be limited due to the performance impact.

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  • Bone Based

Bone Based
Bone Based

Bone-based facial rigs involve the use of a series of bones that the face is skinned to, and these bones are animated directly or via control objects to achieve the desired facial expressions.

This method allows for a high degree of flexibility, as animators can manipulate bones by moving, rotating, or scaling to create varied and dynamic poses.

The ability to adjust animation curves and add keys wherever needed enables more nuanced and believable animations, providing animators with extensive control over the final result.

However, bone-based rigs can be time-consuming to create and fine-tune, especially for new technical artists (TAs) who may not yet have mastered the intricacies of skinning.

The fidelity of bone-based systems is another challenge. Since bones cannot provide the same level of detail as morph targets or blend shapes, achieving fine control over the final shape of the face is difficult without creating an extensive network of bones.

More bones increase the rig’s complexity and the time required for setup and refinement.

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  • Blended Targets

Blended Targets
Blended Targets

Blended targets facial rigs are a highly effective system that provides excellent results quickly, delivering both high fidelity and flexibility. This method primarily uses targets, supplemented by a jaw bone to facilitate mouth opening.

Unlike absolute poses, the targets in a blended rig are designed to be mixed to create final shapes and expressions.

For instance, instead of a single smile target, you have separate controls for mouth corner up, mouth corner out, cheek up, cheek out, and right and left squints. These targets are driven by controls, allowing for nuanced and varied animations.

A significant advantage of blended targets is their ability to create diverse poses without the need for numerous corrective targets.

When the initial targets are well-designed, blending them smoothly is achievable, negating the need for extensive corrective adjustments.

This results in a rig that is quick to build, maintains high fidelity and offers animators the flexibility to achieve different expressions in multiple ways.

However, there are some downsides. Creating a blended targets rig requires more effort compared to simpler systems, but the superior results justify the additional work.

Additionally, while this method is efficient in 3D software like 3DS Max or Maya, it is not as game-engine friendly as bone-based rigs. The rig’s complexity can impact performance, making it less suitable for real-time applications where speed is crucial.

>>>Read more: How to Animate 3D Facial Expressions? A Step-by-step Guide

  • Hybrid Bone & Targets

A hybrid bone and targets facial rig combines the benefits of both systems, aiming to provide the best of both worlds. When executed correctly, this approach delivers a highly flexible and high-fidelity rig.

However, if not done properly, it can result in an overly complex and inefficient system that doesn’t offer significant advantages over a well-made blended targets rig.

In my experience, almost all facial rigs incorporate both bones and targets, with the extent and specific usage varying.

For example, I often include bones for controlling the end of the nose or the brows, while relying primarily on targets for other facial features.

I generally avoid integrating bones into the mouth area due to time constraints and the animators’ limited ability to exploit the added control.

Creating an effective hybrid system requires considerable time and effort.

The goal is to achieve a balance where bones provide the flexibility to translate, rotate, and scale, while targets offer detailed and precise control over facial expressions.

The result should be a versatile rig capable of producing a wide range of facial animations.

  • FACS Muscle Based

The Facial Action Coding System (FACS) is a comprehensive framework that describes the necessary shapes a face can achieve to express a full range of human emotions and movements.

Understanding FACS is beneficial for any technical artist (TA) as it provides deep insights into facial anatomy and expressions, even though it may not be directly applicable to all types of productions.

For example, in stylized animations like “Cloudy with a Chance of Meatballs” or characters like Elastigirl, adhering to real-world facial rules isn’t necessary. However, having this knowledge can be impressive and useful in technical discussions.

Muscle-based facial rigs, inspired by FACS, attempt to simulate the actual muscle movements of the face. While this concept is intriguing, it is often impractical for most projects due to the high demands on budget, time, and expertise.

These rigs don’t necessarily produce better results but rather different ones that may be required for specific, high-end productions.

For the majority of projects, especially those with tight budgets and schedules, simpler and more traditional rigging methods are preferable.

Facial Control Systems

Facial Control Systems
Facial Control Systems

Creating effective facial control systems starts with understanding the type of rig you need and consulting with the animation team. Their input is crucial, as they will be the ones using the system.

I’ve learned that animators’ preferences can vary widely, and it’s important to tailor the controls to their needs, within the constraints of time and budget.

I prefer facial rigs with controls on the face itself, as they provide a more tactile and intuitive experience.

This approach is akin to working with clay rather than a marionette, offering a direct and responsive interaction with the character’s expressions.

However, I’ve experimented with various control systems, including floating panels with joystick controls for pose saving, and spline controls beside the character’s head.

While some innovative ideas in facial control systems gain popularity, they often fade as trends shift.

Tutorials can sometimes mislead animators into adopting impractical methods. It’s essential to discern which techniques are genuinely effective for your specific production needs.

For instance, systems with controls off to the side that load results as large targets might seem appealing but often aren’t practical for most productions. Instead, a camera locked to the character’s head can provide a focused view without unnecessary complexity.

Clean topology is fundamental for achieving the desired results. Proper placement of edge loops and appropriate mesh density are crucial for the rig’s performance and the quality of facial deformations.

Conclusion

Getting the hang of facial rigs is a must if you want to create characters that pop. By exploring the different types of rigs and understanding their pros and cons, you can pick the perfect approach for your project.

Whether you go with bone-based, blended targets, or a hybrid system, it’s all about fitting the rig to your needs and the animators’ preferences. With some practice and a bit of finesse, you’ll be crafting facial rigs that make your characters come alive in no time.

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