In-Betweening in Animation: The Secret to Creating Smooth and Fluid Motion

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Inbetweening or tweening is the process of generating intermediate frames between two images to give the appearance that the first image evolves smoothly into the second image.

Inbetweens are the drawings between the key frames which help to create the illusion of motion. Inbetweening is a key process in all types of animation, including computer animation.

In this article, I’ll explain what it is and how it works. It’s not easy, but it’s worth it because it makes the animation look smooth and lifelike. Let’s dive in!

Decoding the Art of In-Betweening in Animation

Picture this: I’m animating a character who’s about to make a smooth, lifelike jump from one point to another. How do I make sure the movement appears fluid and natural? That’s where in-betweening, or tweening, comes into play. It’s the process of creating intermediate frames between keyframes, which are the beginning and end points of any action. By generating these transitional frames, I can control the smoothness of the animation and make sure my character’s jump looks as realistic as possible.

Traditional vs. Automated Tweening

Back in the day, in-betweening was a manual, labor-intensive process. Animators had to draw each frame by hand, making sure the movement was consistent and fluid. With the evolution of animation software, we now have the ability to automate this process, allowing us to focus on other aspects of the project. Here’s a quick comparison of the two methods:

  • Traditional in-betweening:

– Heavy lifting: animators manually draw each frame
– Time-consuming: can take hours or even days to complete a single scene
– Uncommon in modern animation: mostly used for nostalgic or artistic purposes

  • Automated tweening:

– Software does the heavy lifting: algorithms generate the intermediate frames
– Faster and more efficient: animators can complete scenes in a fraction of the time
– Common in today’s animation industry: used in most projects for its convenience and speed

The Art of Traditional Inbetweening in Animation

Back in the good ol’ days, before the advent of modern technology, creating animation was a pretty labor-intensive process. Animators would painstakingly draw each frame by hand, and inbetweeners played a crucial role in bringing these animated productions to life. Some of the most celebrated movies, like The Lion King, were created using this traditional method.

Rolling Up Our Sleeves: The Inbetweening Process

Inbetweening, or tweening as it’s also known, involves creating intermediate frames between two keyframes. The intended result is to create the illusion of movement by smoothly transitioning one image into another. This process was a cornerstone of traditional animation and required a great deal of skill and patience.

  • Inbetweeners would work closely with the lead animator, who would provide the keyframes.
  • The inbetweener would then create the intermediate frames, ensuring that the movement was smooth and fluid.
  • This process would be repeated for each frame, with the inbetweener carefully refining the edges and adding in the necessary details.

Frame by Frame: The Importance of Frame Rates

In traditional animation, the number of frames per second (fps) played a significant role in determining the quality of the animation. The greater the number of frames, the smoother the animation would appear.

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  • Low frame rates (around 12 fps) were often used for less important scenes or when resources were limited.
  • High frame rates (24 fps or more) were reserved for key scenes or when the animation needed to be particularly smooth and fluid.

Teamwork Makes the Dream Work: The Inbetweener’s Role in the Animation Team

Inbetweening was a vital part of the animation workflow, and inbetweeners were an essential part of the animation team. They worked closely with the lead animator and other team members to ensure that the final product was polished and professional.

  • Inbetweeners would often be responsible for cleaning up rough drawings and making revisions as needed.
  • They would also help to maintain consistency in the animation, ensuring that characters and objects moved in a natural and believable way.

From Past to Present: How Modern Technology Has Changed the Game

With the advent of digital software, the process of inbetweening has changed a great deal. Modern technology has enabled animators to automate much of the inbetweening process, freeing up time and resources for other aspects of the project.

  • Software like Adobe Animate and Toon Boom Harmony can automatically generate inbetweens, making the process much more efficient.
  • However, a skilled inbetweener is still invaluable for ensuring that the automated inbetweens are accurate and true to the animator’s vision.

Mastering the Art of In-Betweening in Animation

Step by Step: The In-Betweening Process

Ah, the in-betweening process- it’s where the magic truly happens. As an animator, I can tell you that it’s both an art and a science. Let me walk you through the steps that I usually follow:

1. Start with the keyframes: These are the crucial beginning and end points of any smooth animation. They define the primary action and set the stage for everything that follows.
2. Add the in-betweens: This is where the technique really shines. By creating additional frames between the keyframes, we can control the motion and make it appear more fluid and lifelike.
3. Refine the arc: A great animation follows a natural arc. Make sure to adjust the in-between frames to ensure that the motion is accurate and smooth.
4. Add the finishing touches: Depending on the medium and style, this could involve adding color, effects, or even additional layers of detail.

Traditional vs. Modern Techniques

In the good ol’ days, in-betweening was done by hand. Traditional animators would draw each frame on a light table, using a pencil and paper. It was a laborious process, but it resulted in some of the most iconic animations in history.

Fast forward to today, and we have a wide array of software at our disposal. Programs like Adobe Animate and Toon Boom Harmony allow us to create in-betweens with greater precision and control. But don’t be fooled- the artistry is still very much alive, and the best animators are those who can seamlessly blend traditional techniques with modern technology.

Why In-Betweening is So Important

You might be thinking, “Why do I need to worry about in-betweening? Can’t I just let the software handle it?” Well, sure, you could. But you’d soon realize that the quality of your animation depends heavily on the in-between frames. Here’s why:

  • It adds life to your character: A well-executed in-between can make your animated character feel more alive and relatable.
  • It ensures smooth motion: In-betweening helps to create a seamless transition between keyframes, resulting in a more polished final product.
  • It allows for greater control: By manually creating in-betweens, you can fine-tune the motion and make sure it follows the arc you have in mind.

Also read: inbetweening is an important part of pose-to-pose animation

Quick Tips for In-Betweening Success

Before I wrap up, let me share a few nuggets of wisdom that I’ve picked up along the way:

  • Practice makes perfect: The more you work on in-betweening, the better you’ll become at it. Don’t be afraid to experiment and try new techniques.
  • Use reference material: Studying real-life examples can help you understand how motion works and improve your in-betweening skills.
  • Don’t cut corners: It might be tempting to skip a few frames or rely too heavily on software, but remember that the quality of your animation depends on the effort you put into it.

So there you have it- a quick guide to the wonderful world of in-betweening in animation. Now go forth and create some amazing animations!


So, that’s what inbetweening is. Inbetweeners are the unsung heroes of the animation world, who make the magic happen by drawing the frames in between the key frames. It’s a labor-intensive process, but it’s the secret to smooth animation. So, don’t be afraid to ask your animator to “please inbetween this for me.” They’ll probably do it for you. So, don’t be afraid to ask! That’s the secret to a great relationship with your animator.

Hi, I'm Kim, a mom and a stop-motion enthusiast with a background in media creation and web development. I've got a huge passion for drawing and animation, and now I'm diving headfirst into the stop-motion world. With my blog, I'm sharing my learnings with you guys.