Game Development Reference

In-Depth Information

If you were writing a game for the Wii or some other platform that can capture a player's

motion, then you can relate the player's swing motion to the initial torque applied to a

virtual golf club, thus determining, through some model, the swing dynamics and re‐

sulting club head velocity.

Golfers take swing technique seriously and so do scientists who study golf swing dy‐

namics. In an effort to understand what makes a good swing or how to improve a swing,

there are many scientists out there actively studying the golf swing physics. As a result,

there are many mathematical models of varying degrees of realism and complexity that

aim to examine the golf swing. One example is the so-called
two-rod model
as described

in Theodore P. Jorgensen's book
The Physics of Golf
. In his book, Dr. Jorgensen describes

the two-rod model in detail, including assumptions and simplifications, and provides

the resulting equations that must be solved to simulate a golf swing based on this model.

He even provides empirical data used to validate the results of the mathematical model.

As shown in
Figure 19-1
, the two-rod model assumes that the golfer's arm is one rod

that extends from the shoulders to the wrists. This is the
arm rod
. The club is represented

by another rod that extends from the wrist end of the arm rod to the club head.

Figure 19-1. Two-rod model of golf swing

This model is essentially a double pendulum. More specifically, it is a driven double

pendulum since the model assumes a torque applied at the shoulder end of the arm rod,

and another torque applied at the wrist joint connecting the arm rod to the club rod.