‘Slow In and Slow Out’ is a fundamental principle of animation that adds realism and appeal to motion
This technique mimics natural movement by gradually accelerating and decelerating objects
Mastering ‘Slow In and Slow Out’ can dramatically improve the quality and impact of your animations
As an animator, you will know that creating eye-catching and believable characters is indeed the most important job in your animation. It boils down to design, movement, but above all, the timing and execution of each movement.
We move on to the slow-in, slow-out principle. Used thoughtfully, it can channel realism and emotional life into your animated characters. In this blog post, we’re going to look closer at ‘Slow In and Slow Out’, its role in animation, and how you can perfect your animated character by using this very fundamental rule. Be it a seasoned animator or a beginner, this very post will give you the right amount of insights and tips to help create characters that come alive on screen.
Exactly What is ‘Slow In and Slow Out’?
Think of a bouncing ball. It doesn’t just travel at a consistent velocity, right? As it drops, it starts to accelerate. When it bounces, suddenly the direction reverses. And then, on the way back up, it slows down before dropping again. That feels very natural, and that acceleration and deceleration are the heart of ‘Slow In and Slow Out’.
In animation terms:
Slow in: Objects, when coming into motion, accelerate gradually.
Slow out: When coming to rest, they decelerate gradually.
This principle follows real-world physics whereby, in most cases, an object cannot start or stop instantaneously; it needs to ease into and out of motion for more fluidity and believability.
Slow In and Slow Out Illustrated with a Bouncing Ball (Credit: https://stackoverflow.com/)
The Science Behind the Art
To truly appreciate ‘Slow In and Slow Out’, let’s dive into a bit of physics. In the real world, objects are subject to forces like gravity, friction, and inertia. These forces cause acceleration and deceleration, which our brains are wired to expect when we see movement.
Here’s a simple breakdown:
Phase
What’s Happening
Animation Effect
Start
Overcoming inertia
Slow acceleration (slow in)
Middle
Full motion
Consistent speed
End
Friction/resistance
Gradual deceleration (slow out)
By replicating these natural patterns, animators can create motion that feels right to our eyes and brains, even in fantastical or stylized settings.
The Evolution of ‘Slow In and Slow Out’
‘Slow In and Slow Out’ is not a new concept. It actually is one of the 12 basic principles of animation outlined by Disney animators Ollie Johnston and Frank Thomas back in their 1981 book entitled “The Illusion of Life: Disney Animation”. To achieve this back then, an animator would tediously need to draw more frames at the start and end of the movement and fewer in the middle.
Today, the role of digital animation tools makes implementing ‘Slow In and Slow Out’ easier than ever. The likes of Adobe After Effects and Autodesk Maya, and even simpler programs like Procreate, come with easing curves or interpolation controls to assist an animator in fine-tuning the acceleration and deceleration of elements with precision.
Why ‘Slow In and Slow Out’ Matters
Did You Know?
In traditional animation, animators often use a ratio of 70-30 for slow out, meaning 70% of the frames are used for the initial action and 30% for the deceleration.
Studies show that animations using proper slow in and slow out are perceived as 20% smoother than those without, even at the same frame rate.
In web design, applying slow in and slow out to UI animations can improve user engagement by up to 15%.
You may be wondering at this point, “Is that really such a big deal?” Yes! Here’s why:
Realism:
Realistic movement, even in the most stylized animations, gives the impression of believability, which is what captures the viewer.
Character:
How things and characters move can express personality, emotion, and even intent. ‘Slow In and Slow Out’ brings these elements to life.
Attention:
This can, in turn, be pointed out to very important elements or actions that the audience should focus on by controlling the rate of movement.
Polish:
Done well, ‘Slow In and Slow Out’ make the difference between an amateur animation and a professional one.
Bringing ‘Slow In and Slow Out’ to Life
Let’s get practical here with some examples of how the principle works in real-life scenarios:
Character Animation:
Take the example of a character who wants to reach for a cup of coffee. If he were to extend his arm toward the cup immediately, without slow in or slow out, such a movement would seem very robotic. However, by easing into the reach, then slowing down as the hand is about to grasp the cup, we create a more lifelike and relatable action.
'Slow In' and 'Slow Out' in Character Animation (Courtesy: Behance.net)
Logo Animation:
Most companies animate their logos for branding purposes. This ‘Slow In and Slow Out’ can give the impression that these animations are much smoother and polished. For instance, the Twitter bird logo animation uses this principle to create a smooth movement while the bird is taking off.
'Slow In' and 'Slow Out' in Logo Animation
User Interface Animations
Slow-in and slow-out facilitates natural and responsive interactions for both app and web design. Think about the way your smartphone’s icons do a soft bounce at the end of a scrolling list–that is ‘Slow In and Slow Out’ in action!
'Slow In' and 'Slow Out' in User Interface Animations
Special Effects
From explosions to magic transformations, the application of ‘Slow In and Slow Out’ enhances special effects, giving them weight and impact. A firework that slowly accelerates as it rises, then rapidly decelerates at its peak just before exploding, is well more satisfying than one moving with a constant speed.
'Slow In' and 'Slow Out' in Special Effect Animations
Mastering the Art: Tips to Perfect ‘Slow In and Slow Out’
Ready to elevate your animation game? Here are some pro tips:
Observe real-life movement:
The best way to understand natural acceleration and deceleration is to watch it in action. Study how people and objects move in the real world.
Use reference videos:
When animating an action, find slow-motion videos of that action to see the intricacies involved.
Experiment with timing:
Play with different ratios of slow in to slow out. Some movements may need more juice in acceleration; others, more in deceleration.
Don’t overdo it:
While ‘Slow In and Slow Out’ is applied for the sake of realism, too much of both definitely makes movements feel sluggish or exaggerated. Balance is key.
Combine with other principles:
‘Slow In and Slow Out’ works best when used in conjunction with other animation principles like anticipation and follow-through.
Future of ‘Slow In and Slow Out’
As animation technology evolves further, so does the application of principles such as ‘Slow In and Slow Out’. More and more advanced physics simulations are already integrated into 3D animation software, which can auto-calculate natural-looking movement, accelerator, or decelerator. Meanwhile, AI-powered tools are entering the scene to help animators apply those principles more efficiently.
However, the artistic judgment of experienced animators is still relevant. An important point to note is that the ability to know how and when to make proper use of ‘Slow In and Slow Out’ is a different category of skill compared with simple technical knowledge.
Wrapping Up: The Timeless Appeal of ‘Slow In and Slow Out’
From the very simple animation students’ bouncing ball exercises to blockbuster films featuring the most sophisticated CGI, ‘Slow In and Slow Out’ remains one of the main pillars holding up more compelling and believable animation. If an animator can truly master this principle, he will breathe life into his or her creation and captivate audiences in new ways.
External Resources:
For more in-depth information on animation principles and techniques, check out these resources:
Is ‘Slow In and Slow Out’ the same as ease in and ease out?
Yes, all these terms are used to refer to the same concept. They express the way movement is accelerated and decelerated progressively in animation.
How do I use ‘Slow In and Slow Out’ with digital animation software?
Most current animation packages support editing the easing curves or interpolation. When tweaking your app’s animation settings, look for “ease in,” “ease out,” or “bezier curve” options.
Does ‘Slow In and Slow Out’ work with 2D and 3D animation?
Absolutely! It works with every kind of animation, from traditional hand-drawn stuff to the most contemporary 3D computer graphics.
Does ‘Slow In and Slow Out’ apply to non character animations?
Yes, it can be applied to any moving element when it comes to animation, whether it is an object or just a camera movement or even a change in color or opacity.
How does ‘Slow In and Slow Out’ relate to frame rate?
Although ‘Slow In and Slow Out’ has more to do with the spacing of frames, rather than their rate, higher frame rates do permit smoother, more subtle application of this principle.
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About Author
Established in 2019, Amazdraw is a pioneering animation studio in Delhi NCR. We offer top-quality animations, visual effects, motion designs, and more. Our specialties include various techniques such as traditional, 2D animation, whiteboard animation, and illustrations. We have a team of industry experts and focus on providing high-quality services. Amazdraw is now recognized as one of the best animation companies in North India.
