# Angles: how the ball really comes off the wall

It is natural to think a ball comes off a wall at the same angle it went in. It nearly does, but not quite, and spin can change it a lot. This guide explains why, and how to aim for it.

## What you expect, and what usually happens

*The short version. Each row is explained on the page it links to.*

| What you might expect | What usually happens | Why |
| --- | --- | --- |
| The ball comes off at the mirror angle. | A dead ball, or any ball hit very hard, comes off **flatter**. A lively ball hit gently and arriving fairly square comes off a little **squarer**. | The ball loses push-out speed (the bounce factor) and the wall grips it along its surface. Which wins decides it. [The wall](https://handball.theperfectship.com/guide/angles/wall.md) |
| The ball keeps its speed off the wall. | It always comes off slower, and slower still off a hard hit or a dead ball. | The ball squashes and does not spring all the way back. [The wall](https://handball.theperfectship.com/guide/angles/wall.md) |
| Topspin keeps a front-wall shot low. | Topspin bends the ball down in the air, but the front wall **kicks it up**: it comes off higher and carries farther. Backspin is pulled **down** and lands nearer. | The wall grips the face of the ball that touches it and pushes the other way to its turn. [Spin](https://handball.theperfectship.com/guide/angles/spin.md) |
| Spin carries on as it was. | The ball keeps turning the same way, but it now travels the other way: **topspin becomes backspin** for the next bounce, and backspin becomes topspin. | The direction reverses; the turn does not. [Spin](https://handball.theperfectship.com/guide/angles/spin.md) |
| Sidespin keeps bending the ball the same way. | It bends one way in the air and **kicks the other way** off the front wall. | Air pushes toward the side the front is turning to; the wall pushes against it. [Spin](https://handball.theperfectship.com/guide/angles/spin.md) |
| A ball with no spin leaves the wall with none. | A ball that arrives at an angle comes off **spinning**, rolling along the wall. | The grip that slows its run along the wall also turns it. [Spin](https://handball.theperfectship.com/guide/angles/spin.md) |
| A pinch (side wall, then front wall) follows the mirror path. | It comes off the front wall **slower and cutting more sharply across** the court. | The side wall sets it spinning, and the front wall grips that spin. [Worked shots](https://handball.theperfectship.com/guide/angles/shots.md) |
| The stroke (overhand, sidearm, underhand) sets the spin. | The hand's path through the ball, and where on the ball you meet it, set the spin. The stroke only makes some paths more likely. | The ball turns the way your hand drags its surface. [The hand](https://handball.theperfectship.com/guide/angles/hand.md) |
| The same aim point gives the same result from any height. | A ball struck from high up arrives steeper, lands **nearer the wall and bounces higher**. | It comes off the wall heading down more steeply. [The hand](https://handball.theperfectship.com/guide/angles/hand.md) |

## Contents

- [The wall](https://handball.theperfectship.com/guide/angles/wall.md): A real ball loses speed off the wall and is gripped by it. The two pull the exit angle in opposite directions.
- [Spin](https://handball.theperfectship.com/guide/angles/spin.md): A spinning ball meets the wall with its surface already moving. The wall pushes against that motion, which can change the exit angle by more than everything on the wall page.
- [The hand](https://handball.theperfectship.com/guide/angles/hand.md): Your hand is a surface too. The spin a ball carries comes from how your hand drags across it, and where on the ball you meet it.
- [Worked shots](https://handball.theperfectship.com/guide/angles/shots.md): Four common shots, each with what you might expect, what the ball usually does instead, and how to adjust.
- [The numbers](https://handball.theperfectship.com/guide/angles/model.md): Every exit line and number in this guide comes from one small, standard model of a ball bouncing with friction. Here is what it assumes and what it leaves out.

## The words this guide uses

- **Arrival angle**: the angle between the ball's path and the wall as it comes in. 90° is straight in; a small angle is a glancing ball.
- **Exit angle**: the same angle as the ball leaves.
- **Mirror angle**: an exit angle equal to the arrival angle, the "angle in equals angle out" rule.
- **Flatter** means a smaller exit angle, closer to running along the wall. **Squarer** means a larger one, closer to straight out.
- **Bounce factor**: the share of its push-out speed (its speed straight into the wall) the ball keeps when it comes off. 1 would be a perfect bounce; a real ball is less.
- **Grip**: the wall's friction along its surface. A ball can **slide** all the way through the contact, or the grip can stop the sliding and the ball **rolls** off the wall.
- **Topspin, backspin, sidespin**: named against the way the ball is travelling (Figure 3, on the [spin page](https://handball.theperfectship.com/guide/angles/spin.md)). The **front of the ball** is the side facing where it is going.

## A note on the game

The game keeps a simpler version of this. A cut shot spins: it bends in the air, gets a small push off each wall in the same direction this guide describes, and hops, runs on or checks up off the floor. But each wall and the floor take away a set share of the ball's speed along them, rather than working out the grip from how the ball is spinning, and a ball struck without a cut never picks up spin from a wall. Where the two differ, this guide describes real play, not the game.

All the guides: https://handball.theperfectship.com/guide.md