VP4 allows the player to set the Field of View (FOV). The FOV adjustment allows the player to adjust the FOV to his computer display screen size and viewing distance. Screen size varies and not everyone has their eyes the same viewing distance from the screen. Viewing distance is not just a preference. The players eyesight and the screen pixel size affect the eye distance from the screen.

Matching the FOV in VP4 to the FOV defined by the screen width and viewing distance gives the most realistic viewing of the pool table and balls. It is most realistic because the perspective is optically correct (at least as close to correct as possible when displaying a 3D image on a flat screen).

So why would you want the FOV set like RL? Because it is a more natural view and matches what you see in RL on a pool table better. This means aiming in VP4 will be more like RL which means that you can take what you learn in VP4 and use it more effectively in RL and vice versa.

Perspective is the main way we see depth and it makes object further from us smaller. With an improper FOV setting, the balls do not size properly with distance as you are used to from RL play. The bottom line here is that if the FOV is too low, then over cutting balls is the result. If the FOV is too high, then undercutting balls in the result.

To calculate FOV for your display measure the width of the display, straight across horizontally. Then measure the distance your eyes are from the screen. The FOV is defined by:

FOV = arctan(screen_width * 0.5 / eye_distance) * 2.0

VP4 takes FOV in degrees so set your calculater to degrees or convert the radians to degrees by multiplying by 57.296.

If you now set the FOV in VP4 to this number, you should have a correct perspective. Note that this assumes you are using the full size of your display when playing, which means full screen mode or maximized desktop window.

In the past some players have lowered the FOV a lot to make the balls larger and aiming more accurate. This was necessary with small display and large pixel sizes or the past. But with today’s larger displays, small pixel sizes, and full screen anti-aliasing, magnifying the ball size is not so important for accuracy and you are probably better off trying to match the perspective.

You can adjust to any FOV setting so nothing says you have to use this method. Legacy VP players tend to like low FOVs because they are used to them. But if you want to have VP4 match your real life pool aiming, it is better to use the proper FOV for your screen size and viewing distance.

Steve Chaplin

Virtual Pool 4 Online