Timing and spacing are two of the most fundamental principles in animation. They breathe life into objects, giving them a sense of weight, momentum, and purpose. While they sound similar, they control different aspects of motion.

• Timing is the duration of an action, measured in frames. It tells you how long it takes for an object to get from one pose to another. More frames between poses mean a slower action. Fewer frames mean a faster one.

• Spacing describes the distance an object travels from one frame to the next. It determines the speed of an object within a given timing. Uneven spacing creates the illusion of acceleration and deceleration, while even spacing results in constant, mechanical motion.

Think of a car journey. The timing is the total trip time, say, one hour. The spacing is how the car's speed changes during that hour. It speeds up on the motorway (wide spacing) and slows down in city traffic (tight spacing).

A bouncing ball is the classic exercise for mastering these principles. Let's start by setting keyframes for the main poses: the highest point, the impact with the ground, and the next highest point.

In Blender's Dope Sheet, you control the timing. The horizontal distance between keyframes dictates how long each part of the bounce takes. If the ball takes 10 frames to fall and 10 frames to rise, the timing is symmetrical.

But a simple set of keyframes will look robotic. The magic happens in the Graph Editor, where you control the spacing. The Graph Editor visualises the object's movement over time as a curve. The steepness of the curve represents speed: a steep curve means fast movement, and a flat curve means slow movement.

The default ease-in and ease-out isn't right for the impact with the ground. A ball doesn't gently slow down before it hits the floor; it stops and changes direction instantly. To achieve this, we need to change the keyframe's handle type.

Select the keyframe at the point of impact in the Graph Editor. Press V to bring up the Handle Type menu and choose 'Vector'. This creates a sharp, linear transition, removing the gentle ease-in. The curve will now form a sharp 'V' shape at the bottom, perfectly mimicking a hard impact.

Now that we have the timing and spacing sorted, we can add more character with squash and stretch. This principle gives the illusion of mass and flexibility.

1. Stretch on Impact: In the frame just before the ball hits the ground, it should be moving at its fastest. To exaggerate this speed, you can stretch the ball vertically along its axis of motion.

2. Squash on Impact: In the frame of impact, the ball's energy is transferred into the ground. It rapidly deforms, squashing flat. The amount of squash tells the audience how soft or hard the ball is. A bowling ball would squash very little, while a water balloon would squash a lot.

3. Stretch on Rebound: In the frame just after impact, the ball snaps back into shape and propels itself upwards. To show this explosive force, stretch it vertically again as it leaves the ground.

Crucially, the volume of the ball must remain consistent. When you squash it vertically, you must stretch it horizontally to compensate.

Finally, ensure the ball follows a natural arc. A thrown object follows a parabolic curve due to gravity. You can edit the motion path directly in the 3D viewport or fine-tune the X, Y, and Z location curves in the Graph Editor to create a smooth, believable trajectory.

Ready to test your understanding?

By manipulating timing in the Dope Sheet and spacing in the Graph Editor, you can turn a simple sphere into an object with convincing weight and physicality.