Definition of A Catch [Archive]

pntbll1313

04-01-2014, 16:36

Based on the two definitions below, a robot gets credit for a catch if they simply impel the ball in a desired direction. So you don't have to "catch" the ball in the way we normally think about it. You just need to push it in a desired direction before it hits the floor and you get full points. Anyone else reading it differently?

The definition of a CATCH:
A CATCH occurs when a BALL SCORED over the TRUSS by a ROBOT’S ALLIANCE partner is POSSESSED by that ROBOT before contacting the carpet or HUMAN PLAYER. An ALLIANCE receives CATCH points only if the CATCH is directly preceded by a TRUSS SCORE.

The definition of POSSESS:
POSSESS: (for a ROBOT) to carry (move while supporting BALLS in or on the ROBOT), herd (repeated pushing or bumping), launch (impel BALLS to a desired location or direction), or trap (overt isolation or holding one or more
BALLS against a FIELD element or ROBOT in an attempt to shield them) a BALL.

MasterEric

04-01-2014, 16:47

You just need to push it in a desired direction before it hits the floor and you get full points.

:yikes: You sir are a genius.

TheDrillKeeper

04-01-2014, 16:52

Pushing it would be considered either a herd or a launch, but would most likely not count as a catch. For it to be a herd, you'd have to hit it more than once before it hit the ground, and for it to be a launch, you'd have to hit a desired location. Simply bumping it with your robot means you have little control over its destination, so it would not be launching it in a "desired" direction.

Kevin Sevcik

04-01-2014, 16:52

Note that humans are going to be scoring this. If it looks like the ball just randomly bounced off your robot, you're probably not going to get those points. I'm thinking it's going to have to be fairly apparent that you've changed the ball's velocity in a controlled and purposeful manner.

nathannfm

04-01-2014, 16:57

wupy36

04-01-2014, 17:24

Can you have more than one catch per cycle at all so for say does it have to be over the Truss to count as a Catch???:confused:

EricH

04-01-2014, 17:40

Can you have more than one catch per cycle at all so for say does it have to be over the Truss to count as a Catch???:confused:

I HIGHLY recommend that you read the Manual, specifically Section 3.1.4.

According to one of the blue boxes...you cannot have a catch without a truss score on the same throw. And according to one of the early paragraphs, truss points are only awarded once per cycle.

themccannman

04-01-2014, 17:44

Can you have more than one catch per cycle at all so for say does it have to be over the Truss to count as a Catch???:confused:

It has to clear the truss to be eligible for catch points. Catch points, like truss points, are only applied once per cycle. Please read the manual more carefully.

In regards to the definition of a catch. A catch is defined as such:

CATCH: the event when a BALL SCORED over the TRUSS by a ROBOT’S ALLIANCE partner is POSSESSED by that ROBOT before contacting the carpet or HUMAN PLAYER.

And here is the definition of possessed:

POSSESS: (for a ROBOT) to carry (move while supporting BALLS in or on the ROBOT), herd (repeated pushing or bumping), launch (impel BALLS to a desired location or direction), or trap (overt isolation or holding one or more BALLS against a FIELD element or ROBOT in an attempt to shield them) a BALL.

The important part here is the definition of "launch". Launch is defined as impelling a game piece in a desired direction. Not trying to lawyer; this seems to mean to me that if you have an angled ramp on the top of your robot that directs the ball in a certain direction when it contacts the ramp that qualifies as impelling in a desired direction. As far as I can tell, if you have a flat, ramp-shaped robot a ball landing on the ramp and bouncing in a desired direction is defined as launching the ball, which qualifies as possession, which makes the catch legitimate.

Jack_O

04-01-2014, 17:48

The ramp idea seems invalid due to the deflection specifications.

wupy36

04-01-2014, 18:35

This is from the game manual 3.1.4 "points are rewarded once per cycle... for each robot catch"

Why is the each used if there is only one?

EricH

04-01-2014, 18:36

What I was trying to say was that are we able to through it without a truss pass over and get points from just a pass to another bot and is that defined at a catch for points?

So throw it they catch it (without a truss pass over) and receive points which doesnt state that anywhere in the Rule/Manual.

Oh, it does. It does indeed. Why do you think we're telling you to read the Manual?

An ALLIANCE receives CATCH points only if the CATCH is directly preceded by a TRUSS SCORE. This means that an ALLIANCE can only receive CATCH points once per CYCLE and will not receive CATCH points if the TRUSS SCORE criteria are not met.

Rypsnort

04-01-2014, 19:13

a system like some of the teams used in breakaway to directed balls from the input ramp into the goals would definitely count as herding a ball in a desired direction.

Siri

04-01-2014, 20:09

I would suggest that this discussion needs to include the Blue Box quote from G12:

Examples of BALL interaction that are not POSSESSION are
A. “bulldozing” (inadvertently coming in contact with BALLS that happen to be in the path of the ROBOT as it moves about the FIELD) and
B. “deflecting” (being hit by a propelled BALL that bounces or rolls off the ROBOT). [emphasis mine]
A BALL that becomes unintentionally lodged on a ROBOT will be considered POSSESSED by the ROBOT. It is important to design your ROBOT so that it is impossible to inadvertently or intentionally POSSESS an opponent’s BALL.A ramp top sounds a lot more like a deflection than a launch: the balls is already being propelled, and it will bounce or roll off you. Sounds very 469-in-2010, actually, not that it matters directly here. (Note that "inadvertent/unintentional" is not included in the definition of deflection, even though it's in the other box's other two points.) I think we'll need a Q&A, probably something about the energy transferred in launching vs deflecting.

Cal578

06-01-2014, 13:57

The description of what's not a Possession (quoted above) seem to make it clear that bouncing the ball off something like a ramp wouldn't count as a Catch.

Maybe it would help if we consider every-day English definitions of Launch versus Deflect. Launching (or propelling) would add momentum to the ball (the ball starts stationary relative to the robot, then exits with a non-zero velocity). Deflecting (or bumping) merely changes the direction of momentum.

Dragonking

06-01-2014, 14:14

Nuttyman54

06-01-2014, 14:30

How about if a robot launched the ball over the truss, then caught and gave it to their teammate all before the ball touches the ground. Would this be considered a successful catch since the ball is in the possession of a second robot before the ball touches the ground.

Seems legit, although it's a bit of a grey area since the blue box below it says a CATCH must be directly preceded by a TRUSS score, so it depends on what is considered "directly".

pntbll1313

06-01-2014, 14:34

Seems legit, although it's a bit of a grey area since the blue box below it says a CATCH must be directly preceded by a TRUSS score, so it depends on what is considered "directly".

Since there is another complete action (possession by the original robot after a TRUSS score) I do not think that really is "directly preceded by the truss score.

Dragonking

06-01-2014, 14:48

Since there is another complete action (possession by the original robot after a TRUSS score) I do not think that really is "directly preceded by the truss score.

The rules specify that the catch must only occur before the ball contacts the ground or a HP.

A CATCH occurs when a BALL SCORED over the TRUSS by a ROBOT’S ALLIANCE partner is POSSESSED by that ROBOT before contacting the carpet or HUMAN PLAYER.

An ALLIANCE receives CATCH points only if the CATCH is directly preceded by a TRUSS SCORE. This means that an ALLIANCE can only receive CATCH points once per CYCLE and will not receive CATCH points if the TRUSS SCORE criteria are not met.

Because of the way this part is explained, I take to only have to do with robot catching a ball that was not shot over the truss.

But I agree this is definitely a grey area and a question for Q and A

jordansch

06-01-2014, 15:23

Here's how I interpreted the rulings here:

It is only possible to score one truss score per cycle, and since you have to get a truss score immediately before a catch, you can only catch once per cycle. As I understand it, you simply must throw the ball over the truss and have an alliance member's robot catch it. Catching would probably entail having a part specifically designed to gain control of the ball, and I highly doubt that judges will consider bouncing a ball off of a plate to be "catching" (and all of their calls cannot be contested).

I do feel confident in my understanding, because our team spends the first four hours of the first day reading completely through the rules, then asking each other for their interpretations on vague rules. I would recommend every team at least make all their members read the rules once, so that they can have some ideas of restrictions they have on their robot and strategy.

Tungrus

06-01-2014, 15:32

Simplified "once per cycle" for catch points is to prevent an alliance playing lacrosse over the truss.

pntbll1313

06-01-2014, 15:41

Catching would probably entail having a part specifically designed to gain control of the ball, and I highly doubt that judges will consider bouncing a ball off of a plate to be "catching" (and all of their calls cannot be contested).

Here's how I interpreted the rulings here:
I do feel confident in my understanding, because our team spends the first four hours of the first day reading completely through the rules, then asking each other for their interpretations on vague rules. I would recommend every team at least make all their members read the rules once, so that they can have some ideas of restrictions they have on their robot and strategy.

I've read the rules 4 times so far and have a very good understanding. I would caution your team to try not to interpret the rules as you see them, but rather as they are written. Saying "Catching would probably entail having a part specifically designed to gain control of the ball, and I highly doubt that judges will consider bouncing a ball off of a plate to be 'catching' " does not help anyone. Try to site directly from the manual. Catching is very clearly defined in the manual, no need for interpretation.

A CATCH occurs when a BALL SCORED over the TRUSS by a ROBOT’S ALLIANCE partner is POSSESSED by that ROBOT before contacting the carpet or HUMAN PLAYER.

Possessing is also very clearly defined.

POSSESS: (for a ROBOT) to carry (move while supporting BALLS in or on the ROBOT), herd (repeated pushing or bumping), launch (impel BALLS to a desired location or direction), or trap (overt isolation or holding one or more BALLS against a FIELD element or ROBOT in an attempt to shield them) a BALL.

I don't doubt that a QA will clarify these things and you may end up being right and interpreted it the way that had meant. However as written, I do not think that is the case.

Sean Raia

06-01-2014, 15:44

It has to clear the truss to be eligible for catch points. Catch points, like truss points, are only applied once per cycle. Please read the manual more carefully.

In regards to the definition of a catch. A catch is defined as such:

And here is the definition of possessed:

The important part here is the definition of "launch". Launch is defined as impelling a game piece in a desired direction. Not trying to lawyer; this seems to mean to me that if you have an angled ramp on the top of your robot that directs the ball in a certain direction when it contacts the ramp that qualifies as impelling in a desired direction. As far as I can tell, if you have a flat, ramp-shaped robot a ball landing on the ramp and bouncing in a desired direction is defined as launching the ball, which qualifies as possession, which makes the catch legitimate.

Nope. Doesnt seem like deflecting a ball at a desired location is possesion to me.

ToddF

06-01-2014, 15:48

pntbll1313

06-01-2014, 15:58

What's good for the goose is good for the gander.

Do you want to count your own ball falling on your robot and bouncing off in the direction of your ramp as a possession? Then you also have to accept that if one of the opponent's balls happens to fall on your robot, and it bounces off in the direction of your ramp, that you have possessed their ball and are guilty of a technical foul.

If it simply falls on a robot and you do not apply a force to the ball I do not think that can be called impelled. I do not think ramps can impel. Remember the definition of launch (one of the ways you can possess a balll) is to "impel BALLS to a desired location or direction". Impelling means to drive, force, or urge. The definition is pretty clear that it needs to be IMPELLED in a DESIRED DIRECTION. That means exert a force that makes it go where you want it to go. Even if the ball happened to bounce off my robot and I did impel it, if it was not in the direction I desired it does not fall under the category of possession. desired=purposeful.

lethc

06-01-2014, 16:44

How about if a robot launched the ball over the truss, then caught and gave it to their teammate all before the ball touches the ground. Would this be considered a successful catch since the ball is in the possession of a second robot before the ball touches the ground.

A CATCH occurs when a BALL SCORED over the TRUSS by a ROBOT’S ALLIANCEpartner is POSSESSED by that ROBOT
before contacting the carpet or HUMAN PLAYER.

Just checked the rules and I can't find anything to invalidate this. Great idea! Just remember that these decisions are left to the referees and they may not count points earned as a result of this method.

themccannman

06-01-2014, 16:48

Nope. Doesnt seem like deflecting a ball at a desired location is possesion to me.

I really doesn't matter what you think. It matters what the refs decide at competition. My post is still correct, as the rules state, controlled direction of the ball is a catch. However I'm pretty sure that either the GDC or refs will change the rule or it's interpretation as soon as someone tries it. I'm betting that they will rule impelling the ball via an angled sheet is not a catch, so I wouldn't put any time into trying that as a strategy since it will become useless after week 1.

EricWilliams

06-01-2014, 17:12

I would suggest that this discussion needs to include the Blue Box quote from G12

I don't understand how this didn't end the debate.

Caleb Sykes

06-01-2014, 20:50

I don't understand how this didn't end the debate.

The reason is that there is still grey area as to what is a "deflection" and what is a "launch". According to the manual,
deflecting = being hit by a propelled BALL that bounces or rolls off the ROBOT
launch = impel BALLS to a desired location or direction

Here are a few examples (note that "hit" in this context denotes some sort of active interaction and "bounce" denotes inactive interaction):
1. A ball scored over the truss comes out of the air to my robot which proceeds to hit the moving ball right into the low goal.
2. A ball scored over the truss comes out of the air to my robot which proceeds to hit the moving ball into a high goal (much larger opening). Although the specific location is not consistent, it still consistently hits somewhere in the high goal.
3. A ball scored over the truss comes out of the air to my robot which proceeds to hit the ball to the ground next to a teammate robot a few feet away.
4. A ball scored over the truss comes out of the air to my robot which proceeds to hit the ball forward relative to the robot. Although there is no specific "location" that the ball goes, the "direction" is consistently forward.
5. A ball scored over the truss comes out of the air to my robot and then bounces on the top of my robot into the high goal.
6. A ball scored over the truss comes out of the air to my robot and then bounces (possibly with the help of an angled top) off the top of my robot to the ground directly in front of an alliance partner.
7. A ball scored over the truss comes out of the air to my robot and then bounces off of my robot in an arbitrary direction.

It should hopefully be pretty clear to everyone that (1) is a launch and that (7) is a deflection. But the question still remains: where is the line drawn between them?

Cal578

06-01-2014, 21:55

How can a bounce possibly be a catch?

The definition of Catch (according to section 3.1.4 of the Game Manual) includes Possession. Possession is defined in 3.2.3.4, and includes Launching but not Bouncing. Launching is further defined in that section to be impelling (which is the same as propelling). There is a clear distinction between Launching (impelling) and Bouncing: Launching adds kinetic energy to the ball, Bouncing merely redirects it. Note that if a bounced balls goes in a desired direction, whether by luck or design), that does not make it a Possession.

A single bounce off a robot is not a catch.

If you disagree, please quote a rule to justify your position.

themccannman

07-01-2014, 04:23

Launching adds kinetic energy to the ball.

Driving forward while hitting the ball is adding kinetic energy to the ball. The issue here is that we don't have a clear definition for what "impelling" means in the terms of frc.

Cal578

07-01-2014, 08:59

Driving to hit the ball may be interpreted as Herding (especially if the robot bumps the ball more than once), and that would qualify as Possession. But the examples given above (particularly the later ones) are the ball hitting a stationary robot, not driving forward.

pandamonium

08-01-2014, 11:52

Pinning or Trapping the ball along the back wall is in my opinion a very easy catch. Even if the ball is not caught this clearly meets the possession rules.

Cal578

08-01-2014, 13:19

Pinning or Trapping the ball along the back wall is in my opinion a very easy catch. Even if the ball is not caught this clearly meets the possession rules.
(coloring mine)
The red part seems like a self-contradiction. But anyway...

If you can pin/trap the ball against the wall, without the ball touching the floor or a human player at any time between the throw and the pin/trap, then I believe it would count as a Catch (for points).

A CATCH occurs when a BALL SCORED over the TRUSS by a ROBOT’S ALLIANCE partner is POSSESSED by that ROBOT before contacting the carpet or HUMAN PLAYER.
(emphasis mine)