Animating a character's movements isn't enough.
If you have two men talking at a bar, you can't just lip sync them and call it a day: you need to take into account background animations, the subtle glass cleaning movements of the bartender, or even the vibrations of the jukebox in the corner.
Sometimes, it's the less obvious secondary actions that make the difference between good and great animation.
Let's have a look at how animators do it in this article, and how you can too!
What is the Secondary Action Principle?
The secondary action principle refers to the additional movements that support the primary actions within a scene.
If a character is waving, the primary action is the arm motion, but the head nodding or hair swaying in response introduces secondary actions that enrich the scene.
Why is the Secondary Action Principle Important?
Secondary actions add depth to characters and their environments without overshadowing the main action. While a character angrily closes a book (primary action), animators can have them tap their foot impatiently (secondary action) to highlight their frustration.
Adding secondary actions results in movements that feel more realistic. The body is a complex system with interconnected parts, and so is our environment or our relational network. When one part moves, another is bound to follow.
It's not just entertaining but also appealing to viewers: secondary actions give rhythm to scenes and prevent them from feeling dull. A character might take a slight pause to scratch their head after delivering a line to give the audience a moment to absorb the dialogue.
1. Start With the Primary Action
Focus on the main action first. It should be clear and purposeful. This is the foundation for any secondary actions. If the primary action is not solid, secondary actions weaken the animation.
Consider this example: if a character is jumping over a puddle, the path of the jump from take-off to landing is your primary action. The jump has to feel natural, so you pay attention to how the character bends their knees, pushes off the ground, and lands.
Once the primary action is smooth and believable, you add secondary actions―the flutter of a cloth or a facial expression of triumph―but it's not a must-have. Lots of low-budget animations forgo secondary actions in most scenes, and it's not the end of the world. Wojack animations don’t even lip syn,c but are still watched by millions:
But even a minimal secondary action like a slight stagger can elevate a basic move like walking. It shows that thought was put into the character's weight and momentum, and invites the viewer to feel the impact physically: you don’t need many layers to create a richer experience!
2. Avoid Over-Animating
Secondary actions add a lot to animations, but it's crucial to strike the right balance with the main action.
Too many movements overwhelm your scene and distract the viewers.
If your character is picking a book off a shelf, a simple hand grasp should be your focus. A head tilt or a shift in weight are subtle yet effective choices for secondary actions because they do not steal attention, but they enrich the moment.
On the contrary, you should avoid unnecessary movements like tapping fingers or exaggerated blinking to avoid cluttering your scene.
To plan these actions effectively, use storyboards: sketch out your scene to visualize where secondary actions fit naturally. Planning allows your animation to stay consistent without needing never-ending revisions.
Observe people doing everyday things: you’ll find most people rarely stand perfectly still. A foot adjusts. A hand brushes against a sleeve. These are natural micro-actions, and mimicking them selectively keeps your animation grounded without going overboard.
3. Experiment with Timing
Adjusting the speed or delay of secondary actions shapes the mood and highlights the main action. By experimenting with timing, you can add nuance.
One practical tool to consider is ghost frames to visualize and tweak the timing of secondary motions. They show how actions unfold over time.
In Blender, onion skinning allows you to see both past and future frames to get a feel of the timing of your animation:
But motion paths are more effective in isolating different body parts:
If a character claps their hands, a delayed head nod or subtle grin amplifies the gesture. This delay allows the secondary action to emphasize the impact of the clap. By carefully timing these elements, you enrich the character’s expression.
4. Don't Forget The Context of The Scene
When using secondary action in your animations, always consider the scene’s context.
If we go back to the example of a character waving, you need to imagine where this action takes place and how it affects or is affected by other characters and the environment.
Consider interactions with the environment or props as rich sources for secondary actions. If your character is drinking coffee, they might fidget with the cup’s handle. This small gesture adds depth to their personality. The steam wafting upwards from the cup introduces a subtle secondary action that adds realism.
Background animations are also crucial. They make the entire environment feel alive. Leaves rustling in the wind or a cat stretching lazily on a warm sidewalk support the story and create a believable world.
By paying attention to the context, you not only improve your primary actions but also enrich the scene with layers of meaning that make for a more memorable experience.
5. Work These Rigs
A rig is the digital skeleton of a character in 3D modeling. It controls how the character moves.
A good rig is crucial for secondary action. When a character nods in agreement, their hair also needs to sway slightly. Your rig needs to support these extra motions.
Rigging artists usually start with Inverse Kinematics (IK) to manipulate limbs and Forward Kinematics (FK) for individual joints. These rig constraints allow animators to make poses.
Only then do they add controls for secondary elements like hair, tails, or clothing.
Sometimes, these secondary elements have their own physics engine to render them more realistically. Typically, photo-realistic hair simulations are extremely resource-intensive:
6. Mastering Layers
When you're working with DCC tools like Maya, Blender, or Toon Boom Harmony, managing layers efficiently becomes crucial to maintain clarity while working with other teammates on a scene.
Main and secondary actions are usually on separate layers. For example, the major body movement should be one layer, while hair, clothing, or a waving hand can be placed on a secondary layer. Animators use layer groups or nesting features to organize related elements and streamline visibility toggling.
Constraint stacks allow animators to create complex hierarchies of animation layers where one action can influence another. It's an advanced technique in tools like Blender, where you can link objects and bones, allowing a base action to be intently nuanced by a secondary one.
Make sure to add metadata to your layers―whether it's through naming conventions, color coding, or notes―to make your models more readable.
Conclusion
Secondary actions are precious storytelling tools to make your animation more immersive.
Getting the primary action right is key, and you should beware of over-animating, but well-timed secondary actions can truly make movements shine or reveal more about the world the characters evolve in.
Secondary actions are not to be confused with overlapping actions, and just like primary actions, you need to plan for follow-through actions. Have a look at our detailed guide on this topic here!
