Robotics Education & Competition Foundation
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Official Q&A: VRC 2023-2024: Over Under

Usage Guidelines All Questions

Field Tolerances Impacting Gameplay


Colin Smith (Event Partner)
17-Jul-2023

(via team 920B) <T10> [...] Field Element tolerances may vary from nominal by up to ±1.0” <T7> Match Affecting “field fault” issues. [...] iii. Field Elements detaching or moving beyond normal tolerances (not as a result of Robot interactions). Grant Cox (chairman of the GDC) clarifies here (https://youtu.be/V0fb47-Zd5Q?t=37) that the goals should be built such that you cannot easily roll the triballs into the goals; they must be pushed with a reasonable amount of force to get them under the PVC bar that defines the outside of the goal. After much experimenting with the field and observing other fields, it has become apparent to us that sometimes the vertical PVC pipes on the corners of the goals will sometimes become raised up due to intense robot interactions. This drastically changes how triballs interact with the goal, namely how easy they roll under. With this and the above rules in mind, we would like some clarification as to how these rules should be interpreted in certain situations. We are not looking for a blanket ruling, and we know that it is impossible to issue one. Instead, we would like a ruling on what the correct ruling should be in the following situations (assuming no other rules are being violated): Situation 1: A robot is pushing triballs into their alliance goal in an act of reasonable normal gameplay. As they are doing so, the vertical PVC pipe in one of the corners of the goal loosens up a little bit and raises up ¾”. Since it is still within the ±1” allowable tolerance, it is not in violation of <T10>. However, it now allows triballs to be easily rolled under the net from several feet away, such that they don’t even contact the horizontal PVC pipe. This does not meet any of the criteria of <T7a>, so the way I read the rule, no replay should be awarded. However, one alliance clearly had an advantage due to their goal being raised up allowing for easier scoring in the goal. After the match, it is determined that the alliance who had the goal that raised up ¾” won, but only because the goal had become raised up. The head referee recognizes this as affecting the outcome of the match, but cannot classify it as match affecting as it does not violate <T7>. What should be done? Should the match be replayed (if so, under what rule)? Should the team that caused the goal to raise up be given a warning (if so, how should the referee determine which robot to penalize)? Situation 2: A robot at the beginning of the match intentionally presses upward on the goal, causing the vertical PVC pipe to slide ¾”, causing the outcome described in Situation 1 (including the head referee determining that it did affect the outcome of the match). The robot did utilize the fact that triballs can easily be rolled into the goal. Does the fact that it was intentional change any of the answers to the questions in Situation 1? Situation 3: The head referee determines after a match has ended that the match had begun with one of the goals raised up ¾” as described in Situation 1. It leads to the same outcome as in Situation 1, where the head referee sees that it did affect the outcome of the match. Situation 4: After a match, the head referee sees that one of the alliance goals is ¾” lower than normal (they are unsure how or when it happened). It is still within the ±1” tolerance set by <T10>. However, this impacts the ability to score triballs in the goal so much that the head referee determines that it did severely affect the outcome of the match. From my observations, it would be unsafe and likely to damage triballs (in violation of <S1>) to design and compete with a mechanism capable of pushing triballs under the bar if it were ¾” lower than normal. What should be done in this situation? Should the match be replayed (if so, under what rule)? Or should the outcome of the previous match just be left as-is and the field be fixed for the next match? Again, we are only looking for answers to these specific situations, not a blanket answer (as we know you cannot provide one). Assume no other rules are being violated in these situations. Thank you for your time and consideration.

Answered by committee
28-Jul-2023

Thank you for your questions. We’ll start by noting that the tolerances for the opening of the Goal between the PVC pipe and the foam tiles was revised to +0.25” / -0.00” in version 1.0 of the game manual on June 27, 2023. This change predated your Q&A post and has a significant impact on your scenarios. As always, we encourage users to review and follow the Q&A Usage Guidelines, which include "Quote the applicable rule from the latest version of the manual in your question. Often, you'll find that by quoting the rule, you'll answer your own question.”

In all scenarios in which the Goal is or becomes out of tolerance due to normal gameplay or incorrect assembly (including your Situations 1, 3, & 4) a Match replay may be warranted under clause aiii of rule <T7>, “Field Elements detaching or moving beyond normal tolerances (not as a result of Robot interactions),” at the discretion of the Head Referee and Event Partner. In these scenarios, no Teams should be penalized.

In scenarios in which the Goal is moved out of tolerance intentionally (including your Situation 2), would merit a Major or Minor <S1> Violation depending on whether the Head Referee determines that the Violation is Match Affecting or not.

To keep events on schedule, Teams that are concerned about a Goal height should notify the Head Referee or event staff prior to the Match.