Basics of 2D animation

Hello students, welcome to Kwickprep. Have you made a flip book, where drawings seem to move as you flip pages fast? That is animation. Today we will learn how animation works, the types of 2D animation, and the key terms used in Synfig.

First, the meaning. Animation is showing many still pictures one after another, very fast. Each picture changes a little from the one before it. Our eyes see this as smooth movement. A cartoon show and a moving logo in an advertisement are both animation.

Why do we see movement at all? The reason is called persistence of vision. The eye keeps an image for a very short time, about one tenth of a second, after it is gone. If the next picture comes before that, the pictures join together in our mind. So a fast series of still pictures looks like motion.

A frame is one single still picture in an animation. Frame rate is the number of frames shown in one second, written as fps. Cinema films usually use 24 fps. Indian TV uses 25 fps. Many online and game videos use 30 fps or more. Below about 12 fps, movement starts to look jerky.

Animation can be 2D or 3D. 2D animation is flat, with only width and height, like Chhota Bheem cartoons. 3D animation also has depth, so you can see objects from all sides, like modern animated films. 2D is easier to learn, so we begin with it. Synfig is a 2D animation software.

There are three common types of 2D animation. In traditional or frame by frame animation, every frame is drawn by hand. In cutout animation, a character is made of separate parts, like paper cutouts joined at the joints. In vector animation, the computer moves shapes and creates the in-between frames.

Now the two most important terms. A keyframe is a frame where you set an important position, like the start or end of a movement. In-between frames are the frames between two keyframes. Tweening means the computer creates these in-between frames by itself. So you draw only the keyframes, and Synfig does the rest.

Let us see tweening with a ball rolling across the screen. At frame zero, the ball is on the left. At frame 24, we move the ball to the right. Synfig fills frames 1 to 23 with the ball in between. When we play it, the ball rolls smoothly for one second.

Pause and predict. You animate a ball at 24 fps, with keyframes at frame 0 and frame 48. How long does the movement last? 48 frames divided by 24 frames per second is 2 seconds. How many frames did you place yourself? Only 2, the keyframes, and Synfig made the rest.

2D animation can use vector or raster pictures. A raster picture is made of pixels, the tiny coloured dots of a screen. It becomes blurry and blocky when made larger. A vector picture is stored as points and curves. It stays sharp at any size, which is why Synfig uses vectors.

Where is 2D animation used? Cartoon shows and short films are the best known use. Education videos use it to explain science and maths. Advertisements and explainer videos use it for products and services. Mobile games and app screens use small animations too.

Let us revise what we learned today. Animation shows still pictures fast, and persistence of vision makes them move. A frame is one picture, and fps is frames per second. 2D is flat, and 3D has depth. You set keyframes, and tweening creates the in-betweens. Vector pictures stay sharp at any size. Make a small flip book tonight to see this yourself.