I did this a long time ago, and posted it in the DDRUK.com forums. There was a good reaction about it, and I’ve been wanting to do it again since I got my new 19″ monitor. So, once again, here it is how to calculate the arrow speed in DDR or similar games.
Actually it’s very simple. You only need to know a few variables, and apply a simple formula. These are the variables you need to know:
- Travelling distance of an arrow in one beat, in pixels.
- Height of the playing screen, in pixels.
- Height of your screen, in centimeters (or inches).
To obtain the first two, just play any song in your DDR simulator or whatever game, and take a screenshot when two consecutive arrows appear - when the distance of such arrows is one beat. I used DWI and Paranoia KCET to do it.
Then use any graphic software to measure the elements. The playing screen is easy, in DWI it’s always 480 pixels high. The travelling distance of one arrow in one beat is the distance between the top of the arrow, and the top of the next arrow. Easy, uh? In my example, it is 64 pixels. (Actually you can get these values just looking at the DWI skin, but this is a more generic approach.)
That means that, in one beat, an arrow travels 64 pixels. Like, how’s that in centimeters, or any other standard measurement? I measured my screen, and the viewing window is 331mm tall. So if 480px are 331mm, 64px are… 331*64/480 = 44.13mm. That’s the distance an arrow travels in one beat. In speed terms, and thinking that the song was one beat per minute, it means 44.13mm per minute. In more normal units, that’s roughtly 0.735mm per second, or 2.648 meters per hour.
That’s with one beat per minute. But at 100 beat per minute, we would just multiply these measures by 100 and done, we have the speed. Here are some examples:
- Bag (65bpm): 47.81mm/s
- Orion.78 AMEuro (100bpm): 73.55mm/s
- Brilliant 2U (150bpm): 110.33mm/s
- Paranoia (180bpm): 132.4mm/s
- Healing Vision Angelic Mix (200bpm): 147.11mm/s
- Drop Out (260bpm): 191.24mm/s
- Max300 (300bpm): 220.67mm/s
- Maxx Unlimited (333bpm): 244.94mm/s
- Portions of Max. Period (600bpm): 441.33mm/s
As you can see, one of the slowest songs, Bag (there are two songs with 63bpm), crawls at not even five centimeters per second, while Max300 goes at 22 centimeters per second. That’s the real speed of those arrows in my screen, and if you have a 19″ monitor, your speed too. To change from milimeters per second, to meters per hour, then you just need to multiply the result by 3.6, and you get the right speed. Paranoia, which once seemed impossible for me, goes at a stunning 476 meters per hour. Not even half a kilometer in one hour. Even the speedy ending of Max. Period at 600bpm is only about 1.5 kilometers per hour (just a bit below one mile per hour for the imperial stubborns).
So if the speediest speedy song is only 1.5 km/h, maybe now DDR will look slower to you… Just take into account that one arrow is in the screen only for less than one tenth of second at 600bpm, and again DDR will look as hard as usual ^_^
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