Bot Questions - socccer ball friction Anonymous - Sat Feb 15, 2003 10:10 pm Post subject: socccer ball friction
how does soccer ball friction relate to the decelleration of the ball
higher frictions make the ball slow down faster but what is the conversion?
1 friction unit = -10 speedunits/second^2 ???
just a guess, anyone know the exact amount?
Doggeti - Mon Feb 17, 2003 6:52 am Post subject:
I don't know the formula but I have an idea how you could find it out. You must have a fixed point on a map from where you shoot the ball (Your ship should not move itself, so i suppose to ba on a saftey-zone-tile). Look how far the ball gets from your position and take the time until it stops. take out some book about physics and look up formulas that contain an acceleration-variable. put in your values and calculate the acceleration.
do all this a second time with other friction-settings. finally compare the two acceleration-values and you should be able to say how the acceleration depends on friction.
I hope all this is easy to understand and correct Helicon - Mon Feb 17, 2003 10:28 am Post subject:
who says estonians follow the principoles of newtonian physics?
Doggeti - Mon Feb 17, 2003 4:07 pm Post subject:
Nobody But it's worth the try, isn't it? Mine GO BOOM - Mon Feb 17, 2003 4:39 pm Post subject:
Everything in SS is controled by physics. And the formula you want is:
X = V*T + 1/2*A*T^2
X = distance traveled
V = initial speed (use the setting in .cfg)
A = acceleration, what you want to find
T = time
To find A:
A = 2 * (X - V*T) / T^2
Report back what you find.
Anonymous - Tue Feb 18, 2003 12:14 am Post subject:
the results are in!
I used the formula Vf^2 = Vi^2 + 2AD because i couldn't accurately measure time.
Also, there's no accurate way to get the exact pixel the ball is on when it stops because once someone picks it up it moves. I tried using large number and picked the ball up from the top in the middle to minimize the error.
Here's what I did: I shot each ball with different settings from a still position. I measured distance and solved for acceleration. then i divided this by the number of friction that was on the ball(so i could see what each unit of F is).
Data:
at F==10 Shot power == 1000 pixels/second each F = -14.6
at F==10 Shot power == 1500 pixels/second each F = -21.8
at F==10 Shot power == 2000 pixels/second each F = -29.0
at F==20 Shot power == 1000 pixels/second each F = -9.9
at F==20 Shot power == 1500 pixels/second each F = -14.7
at F==20 Shot power == 2000 pixels/second each F = -19.6
at F==30 Shot power == 1000 pixels/second each F = -7.9
at F==30 Shot power == 1500 pixels/second each F = -12.0
at F==30 Shot power == 2000 pixels/second each F = -15.7
This seems wrong because as the friction goes up, each friction unit is worth less and less. however the total decelleration does slow the ball down faster at higher friction levels so this is valid.
patterns in the data:
as friction goes up, each friction unit is less and less.
as shot power increases each friction unit is more and more.
possible explanations:
acceleration is not constant???
that physics formula is wrong???
wow that felt like a physics report
if anyone wants solve this mystery, feel free
Anonymous - Tue Feb 18, 2003 1:03 am Post subject:
more testing
all tests were done with initial speed = 500 pixels / second and should be more accurate because i used a ship with prox of 1 when picking up the ball.
there is a pattern, but WTF is it??!?!
Anonymous - Tue Feb 18, 2003 1:52 am Post subject:
Friction | Distance | Acceleration | each F
-----------------------------------------------
11 -- 1611 -- -77.6 -- -7.1
12 -- 1564 -- -79.9 -- -6.7
13 -- 1495 -- -83.6 -- -6.4
14 -- 1452 -- -86.1 -- -5.7
15 -- 1409 -- -88.7 -- -5.9
16 -- 1371 -- -91.2 -- -5.7
17 -- 1334 -- -93.7 -- -5.5
18 -- 1304 -- -95.9 -- -5.3
19 -- 1271 -- -98.3 -- -5.2
20 -- 1224 -- -102.1 -- -5.2
21 -- 1218 -- -102.6 -- -4.9
22 -- 1193 -- -104.8 -- -4.8
23 -- 1167 -- -107.1 -- -4.7
24 -- 1147 -- -109.0 -- -4.5
25 -- 1125 -- -111.1 -- -4.4
26 -- 1105 -- -113.1 -- -4.4
27 -- 1084 -- -115.3 -- -4.3
28 -- 1064 -- -117.5 -- -4.2
29 -- 1049 -- -119.2 -- -4.0
30 -- 1031 -- -121.2 -- -3.9
31 -- 1022 -- -122.3 -- -3.9
32 -- 1018 -- -122.8 -- -3.8
Doggeti - Tue Feb 18, 2003 1:10 pm Post subject:
How did you meassure Vf (It's the speed at a certain point of time, right?)
Edit: I know, you set it to 0 for the time when it stands still.
Dr Brain - Tue Feb 18, 2003 1:15 pm Post subject:
Vf is 0 when the ball is stopped. thats all that matters Mine GO BOOM - Tue Feb 18, 2003 1:44 pm Post subject:
You know, if you want a very accurate way of doing this, you could use a bot to log the packets, or print out the soccer ball packets. It will have the time in 1/100th of a second, shows the exact positions and speeds at each point. I was thinking of doing this with the ASSS server to come up with a good formula for worm holes.
Anonymous - Tue Feb 18, 2003 2:02 pm Post subject:
I may be wrong, but doesn't the ball packet just consist of the time it was fired and the speed/direction it was fired. This is all continuum needs to figure out the position and I think this is why MERV doesn't update it on the EVENT_BallMode every time.
The dodgeball bot (in HZ) somehow knows the exact time the puck is stopped and announces it. Perhaps this bot has unlocked the secrets to friction and ball motion?
Mine GO BOOM - Tue Feb 18, 2003 2:31 pm Post subject:
The server forwards you the packet with the updated speeds/positions every so often, so that bot just tells you when the speed is 0.
Anonymous - Tue Feb 18, 2003 6:52 pm Post subject:
how come MERV doesn't update this information when the speed is 0?
Anonymous - Mon Feb 24, 2003 6:35 pm Post subject:
set it to calculate the acceleration using every 50 as a guide
Vf^2 = Vi^2 + 2AD
so like for 80 I did:
50^2 = 80^2 + 2*A*(318-122) and solved for A
Velocity(p/s):Displacement(p) (ignore the e)
10:3e Accel From Previous: -16.6667 p/s^2
20:19e Accel From Previous: -10.5263 p/s^2
30:44e Accel From Previous: -10.2273 p/s^2
40:79e Accel From Previous: -10.1266 p/s^2
50:122e Accel From Previous: -10.2459 p/s^2
60:177e Accel From Previous: -10 p/s^2 -10
70:246e Accel From Previous: -9.67742 p/s^2
80:318e Accel From Previous: -9.94898 p/s^2
90:404e Accel From Previous: -9.92908 p/s^2
100:499e Accel From Previous: -9.94695 p/s^2
110:549e Accel From Previous: -21 p/s^2
120:610e Accel From Previous: -19.8198 p/s^2
130:670e Accel From Previous: -20.1754 p/s^2
140:736e Accel From Previous: -20.2532 p/s^2 -20
150:809e Accel From Previous: -20.1613 p/s^2
160:882e Accel From Previous: -21.2329 p/s^2
170:971e Accel From Previous: -19.7531 p/s^2
180:1068e Accel From Previous: -19.112 p/s^2
190:1153e Accel From Previous: -19.7674 p/s^2
200:1250e Accel From Previous: -19.8413 p/s^2
210:1311e Accel From Previous: -33.6066 p/s^2
220:1376e Accel From Previous: -33.3333 p/s^2 -35
230:1428e Accel From Previous: -36.236 p/s^2
240:1507e Accel From Previous: -34.2412 p/s^2
250:1579e Accel From Previous: -34.1945 p/s^2
260:1653e Accel From Previous: -34.4595 p/s^2
270:1728e Accel From Previous: -34.8993 p/s^2
280:1810e Accel From Previous: -34.4156 p/s^2
290:1893e Accel From Previous: -34.3949 p/s^2
300:1977e Accel From Previous: -34.5477 p/s^2
310:2040e Accel From Previous: -48.4127 p/s^2
320:2109e Accel From Previous: -46.9697 p/s^2
330:2179e Accel From Previous: -46.7822 p/s^2
340:2251e Accel From Previous: -46.7153 p/s^2 -45
350:2326e Accel From Previous: -46.5616 p/s^2
360:2404e Accel From Previous: -45.5128 p/s^2
370:2480e Accel From Previous: -46.7532 p/s^2
380:2572e Accel From Previous: -44.5122 p/s^2
390:2658e Accel From Previous: -44.5783 p/s^2
400:2742e Accel From Previous: -45.0721 p/s^2
410:2820e Accel From Previous: -51.9231 p/s^2
420:2892e Accel From Previous: -54.6667 p/s^2
430:2967e Accel From Previous: -55.3333 p/s^2
450:3125e Accel From Previous: -55.483 p/s^2
460:3215e Accel From Previous: -50.5556 p/s^2 -55
470:3294e Accel From Previous: -54.4379 p/s^2
480:3379e Accel From Previous: -54.9213 p/s^2
490:3464e Accel From Previous: -55.4572 p/s^2
500:3544e Accel From Previous: -56.6826 p/s^2
510:3615e Accel From Previous: -71.1268 p/s^2
520:3685e Accel From Previous: -72.3404 p/s^2
530:3764e Accel From Previous: -70.2273 p/s^2
540:3837e Accel From Previous: -70.9898 p/s^2 - 70
550:3911e Accel From Previous: -71.5259 p/s^2
560:3991e Accel From Previous: -69.375 p/s^2
570:4069e Accel From Previous: -70.8861 p/s^2
580:4153e Accel From Previous: -70.0413 p/s^2
590:4235e Accel From Previous: -70.3704 p/s^2
600:4316e Accel From Previous: -70.9877 p/s^2
610:4393e Accel From Previous: -78.5714 p/s^2
620:4467e Accel From Previous: -80.7947 p/s^2
630:4539e Accel From Previous: -82.7354 p/s^2
640:4615e Accel From Previous: -82.9431 p/s^2
650:4701e Accel From Previous: -81.1688 p/s^2
660:4780e Accel From Previous: -82.9114 p/s^2 -80
670:4862e Accel From Previous: -81.9876 p/s^2
680:4944e Accel From Previous: -82.0988 p/s^2
690:5036e Accel From Previous: -80 p/s^2
700:5125e Accel From Previous: -79.5991 p/s^2
710:5198e Accel From Previous: -96.5753 p/s^2
720:5278e Accel From Previous: -92.8105 p/s^2
730:5358e Accel From Previous: -92.0601 p/s^2
740:5436e Accel From Previous: -92.6045 p/s^2
750:5517e Accel From Previous: -92.4745 p/s^2
760:5599e Accel From Previous: -92.0732 p/s^2
770:5679e Accel From Previous: -93.8272 p/s^2 - 95
780:5759e Accel From Previous: -94.8347 p/s^2
790:5841e Accel From Previous: -95.0617 p/s^2
800:5925e Accel From Previous: -94.9755 p/s^2
810:5998e Accel From Previous: -110.274 p/s^2
820:6074e Accel From Previous: -108.725 p/s^2
830:6150e Accel From Previous: -108.667 p/s^2
840:6224e Accel From Previous: -109.699 p/s^2 - 110
850:6310e Accel From Previous: -107.143 p/s^2
860:6385e Accel From Previous: -114 p/s^2
870:6463e Accel From Previous: -112.418 p/s^2
880:6547e Accel From Previous: -109.494 p/s^2
890:6627e Accel From Previous: -109.779 p/s^2
900:6722e Accel From Previous: -106.189 p/s^2
910:6789e Accel From Previous: -135.075 p/s^2
920:6866e Accel From Previous: -126.389 p/s^2- 120
930:6947e Accel From Previous: -122 p/s^2
940:7020e Accel From Previous: -123.49 p/s^2
950:7107e Accel From Previous: -120.13 p/s^2
960:7187e Accel From Previous: -119.375 p/s^2
970:7273e Accel From Previous: -115.663 p/s^2
980:7355e Accel From Previous: -116.734 p/s^2
990:7435e Accel From Previous: -118.293 p/s^2
1000:7524e Accel From Previous: -116.906 p/s^2
1010:7599e Accel From Previous: -134 p/s^2
1020:7677e Accel From Previous: -132.026 p/s^2-135
1030:7759e Accel From Previous: -129.574 p/s^2
1040:7838e Accel From Previous: -129.936 p/s^2
1050:7917e Accel From Previous: -130.407 p/s^2
1060:8001e Accel From Previous: -125.595 p/s^2
1070:8073e Accel From Previous: -135.897 p/s^2
1080:8155e Accel From Previous: -134.244 p/s^2
this is friction setting 1 and it looks like there are patterns in the numbers every 100 p/s.
roof_tiles - Sun Mar 23, 2003 4:07 am Post subject: bleh...
bah! you people..yer all here spamming equations and formulas, and dont see that...NONE OF IT MATTERS!..you shoot the ball..it goes off at ball speed...the friction stops it...thats all there is to it
less speed+more friction=quicker stop
more speed+less friction=longer stop
easier to understand than vf0=576*{56:g84-f8X - Y=7} *34=woot
roof_tiles - Mon Mar 24, 2003 4:30 am Post subject:
also, why is this in the bot questions section ?
Anonymous - Mon Mar 24, 2003 8:02 pm Post subject:
bots don't have physics and in order to get the ball position you need to implement physics roof_tiles - Tue Mar 25, 2003 1:36 pm Post subject:
cant you just do get x position and get y position every now and then?..seems easier to me..
Anonymous - Fri Mar 28, 2003 6:48 pm Post subject:
The bot doesn't update the x and y after the ball is fired. So this is why we need physics Helicon - Fri Mar 28, 2003 7:27 pm Post subject:
what do you need it for?
Dr Brain - Fri Mar 28, 2003 9:26 pm Post subject:
One example is to figure a value for ball friction that will make the ball stop just short if they have shot it farther that halfway across the field.
Anonymous - Sun Mar 30, 2003 5:08 pm Post subject:
to call offsides in a hockey/soccer enviroment
to determain when the ball "lagged" through a player
to have a bot know when he's supposed to pick up the ball(when the ball is in his/her prox)
rahXephon - Thu Apr 10, 2003 9:16 pm Post subject:
head ache
But it's worth the try, isn't it? 
