Game Development Reference
In-Depth Information
sport of soccer quickly spread outside Great Britain to Europe, South America, and eventually
all over world.
While there are a lot of other aspects to the game of soccer, such as headers, throw ins, and
the like, in this chapter we will focus on the physics of a kicked soccer ball and how to model the
trajectory of a soccer ball in flight. As was the case with modeling the flight of a golf ball, we
already know everything we need to model a soccer ball in flight. To start our soccer simulation,
let's go over some information about the size, weight, and other specifications of the equip-
ment used to play soccer.
Equipment Specifications
The equipment used in soccer is pretty simple. All you need are a ball, a field, some chalk or
paint to draw lines, and some goal posts. As shown in Figure 7-12, a soccer ball is not a smooth
sphere but rather a shape known as a truncated icosahedron (yikes!). It has 12 pentagon- and
20 hexagon-shaped patches built into the surface of the ball. The specifications of an official
soccer ball are controlled by the Federation Internationale de Football Association (FIFA),
which is the governing body for international soccer. According to FIFA, the ball will have a
circumference of between 0.68 and 0.70
m
and a mass between 0.41 and 0.45
kg
. The corre-
sponding radius of an official soccer ball ranges from 0.108 to 0.111
m
.
Figure 7-12.
A typical soccer ball with hexagon- and pentagon-shaped patches
Soccer is played on a field also known as the pitch. Just as with the soccer ball, FIFA allows
a range of field dimensions for an “official” soccer field. For standard play, the length of the
field must be between 90 and 120
m
, and the width of the field must be between 45 and 90
m
.
For international match play, the field specifications are a bit tighter. The length of the field
must be between 100 and 110
m
and the width can range from 64 to 75
m
. A soccer field also
has various lines, circles, and boxes drawn on it. We won't go into detail on all of them here, but
you can find out exactly what lines should be drawn on a soccer field from the FIFA website at
www.fifa.com
.
The objective in soccer is to kick the ball into the opponent's goal. According to FIFA, the
distance between the goal posts should be 7.32
m
. The distance from the lower edge of the
crossbar between the goal posts to the ground should be 2.44
m
(8
ft
). The goal posts and cross-
bars themselves must be less than 0.12
m
wide.
