The Physics behind Video Games
By Laurin Fisher
Nov
26
Skydiving
What else you need to consider with skydiving is the character movement. When a human is falling you have 2 basic positions you can be in. If you spread eagle you will maximize the drag force on your body and it will slow you down. However, if you go head first you are going significantly faster!
Drag
The Drag equation is the same as for swimming. D=0.5*C*d*A*v^2
Where D is drag
C is the drag coefficient for the medium (in this case Air)
d is the density of medium
A is the cross-sectional area of your object (how much area of your object is facing the drag force? Are you spread eagle or head first?)
v is the object's velocity (meters/sec)
As the picture below shows, it is the projected area not the object's total area, that is used in the drag equation.
(picture taken from http://www.real-world-physics-problems.com/physics-of-skydiving.html)
What you also might like to consider is having the character have a parachute. Remember that this increases your Area in the drag equation and that's why it slows you down.
(Picture taken by me of Legend of Zelda Skyward Sword)
Motion
You should also take into account the character (obviously) is not walking to be able to move, so the motion is going to be restricted by Air Resistance.
The character is not going to be
able to move quickly in a given
direction unless it is down.Moving left to right should feel like air is pushing against you, and the character's body should remain in about the same position.
Flopping and fast direction changes are unlikely.
Unless of course your spinning madly through the air.
(Picture taken by me of Legend of Zelda Skyward Sword)
Further reading
Nov
26
Sum up of Skydiving
What you should take away from all this, is that 2 forces are acting on your falling object. You have to take into account your object needs to feel drag to be realistic for the player. Often this limits fast direction changes and fast motion.