Cel Animation in Explainer Videos

Cel animation is a type of animation used to make “flow-y” types of movement (to put it not-so-technically) and to make motion look more realistic in many cases. In cel animation, the artwork is drawn individually per frame. It’s also referred to as “traditional animation” or “frame-by-frame” animation. It’s very time consuming work and hence also expensive. In the good old days cel animation used to be done using sheets of transparent plastic called “cels” which were drawn onto. These days it’s done digitally but the principle is fundamentally the same with the illustrator drawing the individual frames, usually by hand using a tablet.
 
Here below is an example segment taken from a video that we made, which uses cel animation.
 
cel animated clip
 
Cel animation differs from path-based animation where in the latter the animator will define starting and end-points and the software will create the movement between those points.

 
 

Why use Cel?

It allows you to create a natural, fluid look and is good for animating things like smoke, water and fire. It’s also good for adding personality to character movements. Cel animation allows you to change the shape of objects while it is moving. Let’s say you’re animating a bouncing ball – with path animation a bouncing ball would stay in the same (round) shape but with cel animation you can make it change shape as it hits the ground or flies through the air.
 

 
 

Reasons not to use Cel

Because it’s so time consuming to do it can be quite unforgiving of mistakes. If you change a small aspect of the visuals, e.g. the shape of a character it can lead to a lot of re-work as the frames will need to be re-illustrated. So you can imagine the pain if you create a whole video then show it to the boss who says he’s changed his mind about something important or didn’t notice something earlier! Production cost is also a big factor and so cel animation is more usually used in bigger budget jobs.

 
 

Process

The creative process will sometimes differ a bit for cel-animated work. The workflow will involve creating rough sketches to plan out the poses and motion and then after this is approved then the illustrations will be fleshed out with detail and color. There are tools to speed up and simplify the process, e.g. “onion-skinning” tools which allow the illustrator to more quickly create each frame’s artwork.

 
 

Software

There are a few different software packages that can be used for cel animation. Two of the popular packages out there are Adobe Animate and Toonboom. There is a bit of a learning curve to use each of these, or shall we say “practice curve” so many animators tend to specialize in one of the packages.