Refrees

Rules Judged by the Automated Referee

Kick-Off
Just before a kick off (either before a half time starts, or after a goal), all players must be in their own half. To allow for this to happen, after a goal is scored, the referee suspends the match for an interval of 5 seconds. During this interval, players can use the move command to teleport to a position within its own side, rather than run to this position, which is much slower and consumes stamina. If a player remains in the opponent half after the 5-second interval has expired or tries to teleport there during the interval, the referee moves the player to a random position within their own half.

Goal
When a team scores, the referee performs a number of tasks. Initially, it announces the goal by broadcasting a message to all players. It also updates the score, moves the ball to the center mark, and changes the play-mode to kick_off_x (where x is either left or right). Finally, it suspends the match for 5 seconds allowing players to move back to their own half (as described above in the "Kick-Off" section).

Out of Field
When the ball goes out of the field, the referee moves the ball to a proper position (a touchline, corner or goal-area) and changes the play-mode to kick_in, corner_kick, or goal_kick. In the case of a corner kick, the referee places the ball at (1m, 1m) inside the appropriate corner of the field.

Player Clearance
When the play-mode is kick_off, free_kick, indirect_free_kick, kick_in, or corner_kick, the referee removes all defending players located within a circle centered on the ball. The radius of this circle is a parameter within the server (normally 9.15 meters). The removed players are placed on the perimeter of that circle. When the play-mode is offside, all offending players are moved back to a non-offside position. Offending players in this case are all players in the offside area and all players inside a circle with radius 9.15 meters from the ball. When the play-mode is goal_kick, all offending players are moved outside the penalty area. The offending players cannot re-enter the penalty area while the goal kick takes place. The play-mode changes to play_on immediately after the ball goes outside the penalty area.

Play-Mode Control
When the play-mode is kick_off, free_kick, kick_in, or corner_kick, the referee changes the play-mode to play_on immediately after the ball starts moving through a kick command.

Offside
A player is marked offside, if it is

• in the opponent half of the field,
• closer to the opponent goal than at least two defending players,
• closer to the opponent goal than the ball,
• closer to the ball than 2.5 meters (this can be changed with the server parameter offside_active_area_size).

Backpasses
Just like in real soccer games, the goalie is not allowed to catch a ball that was passed to him by a teammate. If this happens, the referee calls a back_pass_l or back_pass_r and assigns an indirect free kick to the opposing team at the ball caught point but the outside of goal areas. Note, that it is perfectly legal to pass the ball to the goalie if the goalie does not try to catch the ball.

Free Kick Faults
When taking a free kick, corner kick, goalie free kick, or kick in, a player is not allowed to pass the ball to itself. If a player kicks the ball again after performing one of those free kicks, the referee calls a free_kick_fault_l or free_kick_fault_r and the opposing team is awarded a free_kick.

As a player may have to kick the ball more than once in order to accelerate it to the desired speed, a free kick fault is only called if the player taking the free kick

1. is the first player to kick the ball again, and
2. the player has moved (= dashed) between the kicks.

So issuing command sequences like kick-kick-dash or kick-turn-kick is perfectly legal. The sequence kick-dash-kick, on the other hand, results in a free kick fault.

Drop ball

Half-Time and Time-Up
The referee suspends the match when the first or the second half finishes. The default length for each half is 3000 simulation cycles (about 5 minutes). If the match is drawn after the second half, the match is extended. Extra time continues until a goal is scored. The team that scores the first goal in extra time wins the game. This is also known as the "golden goal"" rule or "sudden death".

Rules Judged by the Human Referee

Fouls like "obstruction" are difficult to judge automatically because they concern players' intentions. To resolve such situations, the server provides an interface for human-intervention. This way, a human-referee can suspend the match and give free kicks to either of the teams. The following are the guidelines that were agreed prior to the RoboCup 2000 competition, but they have been used since then.

• Surrounding the ball
• Blocking the goal with too many players
• Not putting the ball into play after a given number of cycles. By now this rule is handled by the automatic referee, as well. If a team fails to put the ball back into play for drop_ball_time cycles, a drop_ball is issued by the referee. However, if a team repeatedly fails to put the ball into play, the human referee may drop the ball prematurely.
• Intentionally blocking the movement of other players
• Abusing the goalie's catch command (the goalie may not repeatedly kick and catch the ball, as this provides a safe way to move the ball anywhere within the penalty area).
• Flooding the Server with Messages. A player should not send more than 3 or 4 commands per simulation cycle to the soccer server. Abuse may be checked if the server is jammed, or upon request after a game.
• Inappropriate Behavior. If a player is observed to interfere with the match in an inappropriate way, the human-referee can suspend the match and give a free kick to the opposite team.

Source:
http://sourceforge.net/apps/mediawiki/sserver/index.php?title=Users_Manual/Overview