WEEK 1

[SciBorg Dave]

What have we learned from week 1 ?

[davidthefat]

Many teams will go for the bridges during autonomous. Almost all teams will be able to balance in one way or another.

[ttldomination]

It's not over yet.

- Sunny G.

[SenorZ]

I've learned (from watching streams) that there are a lot of teams that are struggling.

[ttldomination]

I've learned (from watching streams) that there are a lot of teams that are struggling.

Well, week 1 just ended for my team.

Struggling is the right word. Teams were able to line up their robots perfectly during the build and shoot three balls in, but they didn't realize that they can't do that during the matches.

I learned.

(1) Strategy is so big. It's so big it's not even funny.

(2) Scoring is...big. It's bigger than years before because in a lot of cases, the number of points doesn't seem to climb over 10-15. So if you can score in autonomous and teleop and set yourself up with 15-20 TP points, you're going to win a lot of matches.

(3) Bridge balancing. Obviously it's important but teams need to play around with this. There were so many tipped over robots simply because of the lack of communication. You can't simply do what works for your robot. You have to do what works for both robots.

(4) Scoring from the fender. I knew that scoring from the fender would be important, but the crew at Alamo proved just how valuable. Teams would just get comfy up against the fender and lay in 6-9 points easily. If your team that do that quickly, a match score of 40-50 isn't hard to achieve.

(5) Finally, three bots balancing is difficult but not impossible.

We managed it 2-3 times in practice, but couldn't pull it off in a match where it counted.

http://dl.dropbox.com/u/1452690/430028_2704886434169_1617000725_1863379_1714513763 _n.jpg

See everyone in Week3,
- Sunny G.

[stundt1]

I would have to say I think coopertition screwed up seeding making all of the alliances leveled.

Making it anybody's game to win. I see no dominate bots really.

Strategy will be huge this year more than past years.

I am not in favor of the coopertition leveling the alliances It is too much ranking points.
If they made it 1 point then It would be better.

[pfreivald]

(1) Strategy is so big. It's so big it's not even funny.

(4) Scoring from the fender.

In eliminations, we're finally seeing fender-scoring robots being defended against, and it matters quite a bit. I've been perplexed about the lack of defense on fenderbots for two days.

[Littleboy]

In eliminations, we're finally seeing fender-scoring robots being defended against, and it matters quite a bit. I've been perplexed about the lack of defense on fenderbots for two days.

Exaclty how are they being defending? Preventing? Pushing?

[PayneTrain]

What's happening is that one team gets a nice 15 point lead, then a robot will break off from scoring to disrupt the other team the entire match.

I've been watching match results come in. There's around a 40-50% chance that if your alliance can double balance, you can win a match. Endgame matters just as much in 2012 quals as 2011 quals. However, if you can't pick up any points in hybrid or non-endgame teleop in the elims, start packing up.

[pfreivald]

Exaclty how are they being defending? Preventing? Pushing?

Park against the fender, push sideways if necessary.

[Andrew Lawrence]

Park against the fender, push sideways if necessary.

So what are the ways around this for fenderbots?

[PayneTrain]

Find a way to stay still.

In 2006, our team built a system that dropped incredulously high friction pads all around the robot so we couldn't be touched when we scored. If we were to have kept that subsystem on this year, that would have been something that could help.

[pfreivald]

So what are the ways around this for fenderbots?

As far as I can tell, unless you've anticipated it and built a robot to deal with it (a high-traction drive train and a sideways scoring mechanism, for example... or being able to score from both the front and the side of the fender), you're going to have a hard time dealing with a defensive robot that can prevent you from getting to your scoring position.

I'm sure people more clever/insightful than I am can come up with other solutions, too.

[davidthefat]

What's happening is that one team gets a nice 15 point lead, then a robot will break off from scoring to disrupt the other team the entire match.

I've been watching match results come in. There's around a 40-50% chance that if your alliance can double balance, you can win a match. Endgame matters just as much in 2012 quals as 2011 quals. However, if you can't pick up any points in hybrid or non-endgame teleop in the elims, start packing up.

Our bot is not capable of scoring at all... Or even effectively feed:( :( :(

[Andrew Lawrence]

As far as I can tell, unless you've anticipated it and built a robot to deal with it (a high-traction drive train and a sideways scoring mechanism, for example... or being able to score from both the front and the side of the fender), you're going to have a hard time dealing with a defensive robot that can prevent you from getting to your scoring position.

I'm sure people more clever/insightful than I am can come up with other solutions, too.

What about scoring.....from the side? (into the middle hoops?) ;)

[pfreivald]

What about scoring.....from the side? (into the middle hoops?) ;)

Yup. :D That works, too -- though you're limited to one side because of your opponent's alley. (I'd be shocked if there aren't other strategies/builds that enable fenderbots to circumvent or mitigate defense.)

[Andrew Lawrence]

Yup. :D That works, too -- though you're limited to one side because of your opponent's alley. (I'd be shocked if there aren't other strategies/builds that enable fenderbots to circumvent or mitigate defense.)

All I know is front or side, 256 is just rocking those middle hoops like they're nobody's business. :)

[davidthefat]

Anyone see a defensive or a feeder bot? From what I have seen, there was only offensive bots.

[pfreivald]

All I know is front or side, 256 is just rocking those middle hoops like they're nobody's business. :)

I would expect no less! 256 is a powerhouse for a reason.

[372 lives on]

yeah, david team 3325 is defensive.

alamo 1st seed alliance

[Andrew Lawrence]

I would expect no less! 256 is a powerhouse for a reason.

.......Do you mean 254? I'm going to be honest with you. I would never call 256 a powerhouse now. maybe in a year or two (or by week 5, depending how we do). We're a great team, but not a powerhouse yet. We strive to be one, and have been taking the 973 approach to things, since they are a successful team we greatly admire, and one of the best teams in my personal opinion, and pushing ourselves this year to do our best. Maybe we'll be successful. Maybe not. But until then, we are team 256. Just team 256.

Thank you very much for the compliment, but we're not a powerhouse yet. :) But, keep an eye out for us at the Silicon Valley and Central Valley, and you can see what we've come up with this year. :)

[Deetman]

While I was not coaching or driving (those days are long gone...) it appears to be important for balancing that one robot does the majority of the work. The most effective balancing seemed to come from one robot tipping the bridge, driving up but keeping it tilted, and the second robot pushing the first up the bridge and knowing the sweet spot for stopping. It also helps a bunch if a robot won't slip down a tilted bridge with no power applied to the wheels.

[Mastonevich]

1. Hybrid mode really can make a difference. There is the potential to score 36 points. That amount of points can win several matches.

2. To get a high seed, a team must have many matches where they balance with the opposite alliance on the coopertition bridge. This can not be stressed enough.

3. Balancing on bridges wins matches.

4. To win most regionals you will have to be proficient at scoring in the 3 point hoop. This can be done from the key portion with great accuracy.

[JosephC]

1. Balancing 3 robots is possible, and was a major game changer in a few elim matches.

2. It is possible for Inbounders to make baskets from their stations.

3. The Coop points are VERY important to make it to the top seed. Team 1684 Chimeras was the #1 seed for the entirety of Friday at Kettering because they balanced the center bridge 4 times.

4. I can't wait for Week 2. After watching all of the webcasts (thanks coderedrobotics.com) I can hardly wait until we get our chance to show what we're made of.

5. I REALLY need to finish our camera tracking and autonomous code.

[JABot67]

5. I REALLY need to finish our camera tracking and autonomous code.

If you can't do camera tracking, just focus on shooting well from the key. I was very surprised at how well my team did without working camera tracking code.

[Mastonevich]

One of the winners at KC did not have camera tracking. They use the camera to line up though. They were one of the best shooters at KC by far.

[Dusk Star]

1. Triple balancing will be difficult, if not impossible. Ove the entire time at Kettering, not a single alliance managed it. However, double balancing will almost always win the match in seeding matches, and helps enormously in elims.

2. The coopertition bridge is really dangerous. I saw at least 20 teams flip while trying it- much more than the alliance bridges.

3. A slow (shots per second), close range shooter mechanism is much more valuable than a powerful, inaccurate one. There simply aren't enough balls on the field to really allow an inaccurate shooter to thrive.

4. Lining up both power and direction in teleop is harder than one would think.

5. As an addition to 4, vision can be very useful- teams that could have the robot aim, even if it took 15-20 seconds, for them were much more effective.

6. Enough robots will have a bridge manipulator that a small subset of teams can survive without one, and still climb the bridge. You just need something else to make yourself useful ;)

7. Have some way to tell if there is a ball under the bridge you are trying to press down. I saw many teams pushing against a ball again and again, only to have it push the bridge back up before they could get it low enough...

Personal note: at Kettering, it was ruled that [G28] is transitive, same as pinning is. In other words, if blue robot A is touching the key, blue B is touching A, and red robot C touches blue robot B, they are in violation of [G28]. My team got called on that 3 times (same match), and when we challenged it afterwards the head referee said the above. We were REALLY ANNOYED, as it brought us from a tie to a loss. And this was after we had rolled down the coopertition bridge after a failed balance, to prevent the other team from falling off. And the robot on the key was dead, so it wasn't even like we trying to disrupt them... Does this sound correct to anyone else?

[RufflesRidge]

Does this sound correct to anyone else?

Yes, this was asked and answered twice on the Q&A. G28 is transitory.

[Dusk Star]

Yes, this was asked and answered twice on the Q&A. G28 is transitory.

Ah, ok. I hadn't known this... they really should put that type of thing in a rules update. Thank you!

[1986titans]

Anyone see a defensive or a feeder bot? From what I have seen, there was only offensive bots.

There was a defensive bot in KC if you don't count bridge manipulation as offense.

[KrazyCarl92]

Stats from GSR (comprehensive match scouting): 30/50 teams scored in hybrid
18 teams scored in the top, 28 in the middle, and 9 in the low
Teams who shot a considerable number of balls, accuracy ranged from 0 to 83%
28 teams balanced at some point
some inbounders are really really bad...

Fender scoring dominates quals because few ranged shooters can keep up. And no one played defense consistently, which made for a very very boring game.

I hated Rebound Rumble, until I saw teams 1519, 885, and 2791 play in eliminations. It was boring; no defense, and all the matches were the same. They played the best defense as an alliance I have ever seen in an FRC game. If 2791 kept working, they win the regional in DOMINANT fashion. Their gameplay showed how STRATEGY aligned with good robots that fit a strategy can win matches against teams they are "overpowered" against. Hybrid is super important, both scoring and getting balls from the bridge as fast as possible.

Defensive robot is the most valuable robot on the field, which makes the ability to shoot from the key AND the fender important. If you can't access one, go to the other. Exclusively fender scorers may get a false sense of dominance if there continues to be a lack of defense in the quals.

Also balls that are worn down go much shorter than competition quality balls. The bane of Team 20....turned a 60% shooter into a 3-basket-the-entire-tournament atrocity. It was repeatably about 3-4 feet high, but we have plans for easy adjustment at future events, and also to shoot from the fender :). Bridges are much harder to push down than FIRST's battery test implies.

[cire]

Stats from GSR (comprehensive match scouting): 30/50 teams scored in hybrid
18 teams scored in the top, 28 in the middle, and 9 in the low
Teams who shot a considerable number of balls, accuracy ranged from 0 to 83%
28 teams balanced at some point
some inbounders are really really bad...

Fender scoring dominates quals because few ranged shooters can keep up. And no one played defense consistently, which made for a very very boring game.

I hated Rebound Rumble, until I saw teams 1519, 885, and 2791 play in eliminations. It was boring; no defense, and all the matches were the same. They played the best defense as an alliance I have ever seen in an FRC game. If 2791 kept working, they win the regional in DOMINANT fashion. Their gameplay showed how STRATEGY aligned with good robots that fit a strategy can win matches against teams they are "overpowered" against. Hybrid is super important, both scoring and getting balls from the bridge as fast as possible.

Defensive robot is the most valuable robot on the field, which makes the ability to shoot from the key AND the fender important. If you can't access one, go to the other. Exclusively fender scorers may get a false sense of dominance if there continues to be a lack of defense in the quals.

Also balls that are worn down go much shorter than competition quality balls. The bane of Team 20....turned a 60% shooter into a 3-basket-the-entire-tournament atrocity. It was repeatably about 3-4 feet high, but we have plans for easy adjustment at future events, and also to shoot from the fender :). Bridges are much harder to push down than FIRST's battery test implies.

Thanks for the stats, this year seems to have a pretty high percentage of autonomous scoring teams relative to other years. This may be because the fact that you don't need to drive anywhere to try for a point in autonomous though.

Can you (or anyone) elaborate on the "competition quality" balls? Were all the balls the same, or did they vary much like a lot of teams reported on these forums during build? Were they all more firm, non deflated? At what point did they replace the balls, if at all?

Thanks!

[Deetman]

Can you (or anyone) elaborate on the "competition quality" balls? Were all the balls the same, or did they vary much like a lot of teams reported on these forums during build? Were they all more firm, non deflated? At what point did they replace the balls, if at all?

Thanks!

From my viewpoint observing in the stands, the "quality" of the balls in play generally seemed to exhibit general wear and tear akin to what teams noticed during build season. At Hatboro-Horsham it appeared that if a ball was largely intact (no significant divots or gouges) it was used. If a ball sustained significant damage it was removed from play after the match. I know I saw at least two ball-hats.

2018 (HH winning alliance, 2nd seed) had a unique system on their robot that measured the compression of the balls and adjusted their shooter accordingly. Talking with someone in their pits, their testing showed that a 10% variability in compression could result in shot variances of 10 feet.

[Andrew Lawrence]

From my viewpoint observing in the stands, the "quality" of the balls in play generally seemed to exhibit general wear and tear akin to what teams noticed during build season. At Hatboro-Horsham it appeared that if a ball was largely intact (no significant divots or gouges) it was used. If a ball sustained significant damage it was removed from play after the match. I know I saw at least two ball-hats.

2018 (HH winning alliance, 2nd seed) had a unique system on their robot that measured the compression of the balls and adjusted their shooter accordingly. Talking with someone in their pits, their testing showed that a 10% variability in compression could result in shot variances of 10 feet.

How'd they measure it?

[ThirteenOfTwo]

I'l try to only add things that I didn't see mentioned yet in this thread.

Seeding rounds were being really boring because no one was playing defense, but I saw a lot of teams playing in ways that were just completely wrong. There was one team in San Diego who failed to balance on the coopertition bridge, so they went over, touched the opposing alliance's bridge (a nine-point technical foul), and then drove away and ended the match. I don't know if it hasn't sunk in yet, but your opponent's score this year DOES NOT MATTER. Especially if you have robots in your alliance that can't score, it is in your interest to win matches in qualifiers by playing defense! A lot of teams have some really weird ideas about seeding this year...

Two teams in San Diego had my favorite idea of the week--the 2v2 Qualification Match. At the beginning of the match, they sent one team from each alliance, neither of whom looked like they could score, to the coopertition bridge to lock down the bonus points. That's a terrific idea. The coopertition bridge is hard, and you need a lot of time to get on it... what is a robot that can't score going to do that's worth more than 2 QP?

[KrazyCarl92]

Our team sank 60% our shots in practice at our field in the top basket. Competition field, in the 7 matches out of 10 we were mechanically okay we shot around 4-8 shots per match and sank 3 all tournament, shooting almost all of our misses 3-4 feet high. The worn out balls squish easier than the ones on the field I believe (trusting the word of my drivers who felt both balls, and the physics that make sense). Our targeting system is unaffected by lighting changes from practice field to field, as evidenced by saving images to the cRio in match to check to see if that was the problem.

The physics behind this makes sense. If a ball is squisher, it will compress more easily. Since less force is needed to compress it, it will mean less normal force between the wheels and the ball, less frictional force, and less speed coming out. A firmer ball will take more force to compress to the same dimension, which means more normal force, and therefore friction, between the ball and the wheel leading to an increase in muzzle velocity. We're fairly certain the angle of our shooter didn't vary from practice field to competition, so the only thing is speed...which we can only attribute to the balls. We went to the practice field at competition and used our own balls (worn out and squishy) to shoot, no problems! So we need to find some way to account for that discrepancy.

picture of our robot: http://www.chiefdelphi.com/media/photos/37578

[davidthefat]

Wait, does this mean that our robot with 14 inch wheels, a terrible kicker and a bridge lowering mechanism actually has a chance this year? I balance solo in 4 seconds, two bots in about 15 to 30, depending on the other driver. For pete's sake, we have a KICKER... Let's just say I'll focus on defense.

[KrazyCarl92]

For pete's sake, we have a KICKER... Let's just say I'll focus on defense.

Defensive robots are very effective, so don't worry. Sounds like you play the bridge great. Scoring in auto is huge, so at least try to do that, even if in the low basket. Also, if said kicker could clear some balls while playing effective defense (e.g. between pins), then you could be a GREAT eliminations partner.

[Hebrew]

So a good strategy for a defensive robot seems to be just parking up at the fender to stop dumping robots?

Where would be the best place to balance at if our robot is only 90 pounds including battery?

Any other good defensive strategies for a team that has no shooter, just an arm to lower/raise the bridge, I am interested since our team has never been to a competition before :eek:

[ThirteenOfTwo]

So a good strategy for a defensive robot seems to be just parking up at the fender to stop dumping robots?

Where would be the best place to balance at if our robot is only 90 pounds including battery?

Any other good defensive strategies for a team that has no shooter, just an arm to lower/raise the bridge, I am interested since our team has never been to a competition before :eek:

Can you hold balls so that you can ferry them from one side of the field to another? If not, then crossing the bridge to play defense at the beginning of the match is the best possible idea, but make absolutely sure that you don't get any penalties. See if you can write autonomous code to lower the bridge in the center of the field.

[Koko Ed]

I've learned (from watching streams) that there are a lot of teams that are struggling.

this.:(

[RufflesRidge]

Where would be the best place to balance at if our robot is only 90 pounds including battery?


Directly above the extra 40lbs of ballast I would recommend bolting onto your robot at the competition. From observation it is very difficult to balance 2 if the second one is light, as the first bot moves up the bridge to give the second space, the light bot isn't heavy enough to hold it down so it starts to tilt and they flip, even when the 2 robots stay very close together.

[SciBorg Dave]

During week 1 many teams had a problem tipping the bridge. This made me think how many teams added the needed 200 pounds of weight to there practice bridges. We found that the added 200 pounds made the bridge much hard to tip. I saw 1 teams arm bend when they tried to tip the bridge.
It also seem that many team practice tipping with out the bumpers on, when the arm came down the bridge got caught between the bumper and the arm.

[flippy147852]

During week 1 many teams had a problem tipping the bridge. This made me think how many teams added the needed 200 pounds of weight to there practice bridges. We found that the added 200 pounds made the bridge much hard to tip. .

A lot of teams at Gull Lake were trying to tip the ramps with a window motor, and it just wasn't cutting it. They needed a lot more pushing force to tip the bridge.

[pfreivald]

:ahh: We didn't add anywhere close to 200 pounds... I think we added 120 -- but we used the battery test as indicated on the field tour videos.

Here's hoping!

[XaulZan11]

How successful was camera tracking week 1? I know in the past there has been a lot of varability and trouble due to inconsistent lighting.

[Andrew Lawrence]

Wait, does this mean that our robot with 14 inch wheels, a terrible kicker and a bridge lowering mechanism actually has a chance this year? I balance solo in 4 seconds, two bots in about 15 to 30, depending on the other driver. For pete's sake, we have a KICKER... Let's just say I'll focus on defense.

David, a robot with the abilities you described has a certain niche imperative to winning this game: A feeder. If you could hold one to three balls, and then kick them back to your alliance's side, you effectively starve the opponents of balls to score with and feed your alliance. I know I'd want a feeder bot on my alliance, especially one that does the bridge well.

I'm just curious; Are you wide or long (robot)?

[JewishDan18]

How successful was camera tracking week 1? I know in the past there has been a lot of varability and trouble due to inconsistent lighting.

It worked great for Team 20. It rarely failed, but we suffered from other problems.

[davidthefat]

David, a robot with the abilities you described has a certain niche imperative to winning this game: A feeder. If you could hold one to three balls, and then kick them back to your alliance's side, you effectively starve the opponents of balls to score with and feed your alliance. I know I'd want a feeder bot on my alliance, especially one that does the bridge well.

I'm just curious; Are you wide or long (robot)?

It was designed to be a feeder, but I am highly skeptical of its ability to kick the balls effectively enough. It is a long bot. I have been very against this design, but I guess I see a silver lining. The main issue is that we will end up running over the balls, so we would have to back up to kick it. I rather not waste my time lining that up and trying to kick. It has no ability to "dribble" balls, or even hold onto it.

[Talks Too Much]

Our tracking software didn't have any problems at HH, which took place in a gymnasium.

[ColdRail]

:ahh: We didn't add anywhere close to 200 pounds... I think we added 120 -- but we used the battery test as indicated on the field tour videos.

Here's hoping!

SciBorg Dave and I mentor together on team 4061. I helped with the bridge calcs and tipper design....Actually we added 140 lbs to our bridge which weighed 104 lbs unweighted. That got us in the range of the calculated bridge weight using statics calculations for a total bridge weight of 244 lbs based on parameters from the battery test video. Once our bridge was weighted we never got the battery test to work exactly like the video but got very close. We felt this was likely due to differences in our hinge mechanism and minor variations in our wood bridge construction compared to the competition bridge design. We designed for a 2X torque margin (mini-van door motor and gearing) to make up for any calculational uncertainties as well as wanting to ensure that we did not blow any fuses during a match due to the tipping motor pulling excessive current.

In our own testing, our tipping system works very well with power to spare (imagine a robot doing push-ups or a low-rider car with hydraulic suspension hopping up and down!). The real test will be our first ever competition in Cheney Washington April 5-7.

[pfreivald]

In our own testing, our tipping system works very well with power to spare (imagine a robot doing push-ups or a low-rider car with hydraulic suspension hopping up and down!). The real test will be our first ever competition in Cheney Washington April 5-7.

We tweaked our bridge so that it was harder to tip than the battery test would have made it, and our manipulator worked just fine. I'd claim I'm not worried, but I'm always, always worried!

[davidthefat]

Well, it turns out that the top seed at San Diego is 4161. The do not shoot from what I hear from a little birdie at San Diego, all they did was coopertition.

[littlejimmy1058]

Week 1 is never perfect!!

[George Nishimura]

As far as I can tell, it's all about teamwork. Timing, possession and consistency.

[Wayne TenBrink]

I learned that when you go into Week 1 at 119.8 lb, you can't add new stuff without taking something off. Hmmm. Software upgrades work. 1's and 0's are light.

A few of the things that would be useful on the robot:
- A good way to see under the far side of the bridge.
- A good way to clear balls from under bridges.
- A good way to tip the bridge to your side without any of the balls going under the bridge.
- A good way to tip the bridge for somebody else without blocking their path or having to lead them over the bridge.
- A better way to keep balls from getting rolled under the chassis.
- Shooter wheels that aren't affected so much by ball variation.

[Joe Schornak]

Something that surprised me at San Diego was how different alliance selection ended up being in comparison to previous years, mostly because the coopertition bonus allows teams that cannot shoot baskets consistently to seed very high. In every previous regional that I have attended, the uberbots who could hang all the rings or score all the balls invariably seeded in the top eight, and alliance selection consisted of the 1st seed picking the 2nd seed, the 3rd seed becoming the 2nd seed and picking the new 3rd seed, and so on. At San Diego, no alliance's 2nd pick was from the top eight, since most of the really strong scorers had been too specialized towards shooting to do coopertition in many matches. This meant that the elimination alliances were more balanced than in previous years, and I did not get the impression that any one alliance was significantly stronger than the others.

Based on these observations and from looking at the team ranking charts, I have concluded that it may be more important to get coopertition points than to win a match if one wishes to be highly seeded, which strikes me as somewhat counterintuitive to my competitive sensibilities but probably reasonable. Has anyone calculated any sort of "sweet spot" for number of matches won without coopertition vs. matches lost with coopertition? Would it even be possible to calculate this?

On the whole, I really like Rebound Rumble. The qualification matches can be rather boring if everyone just stays on their own side, but the endgame is very tense and exciting, especially in the eliminations when an alliance goes for a three-bot balance and only makes it in the last few seconds. Near-realtime scoring is a very good thing, since I don't have to wait until the end of a match to see who actually won after penalties are calculated. I look forward to seeing how everyone adapts and adjusts in reaction to what we have learned this weekend.

[Randomness]

Based on these observations and from looking at the team ranking charts, I have concluded that it may be more important to get coopertition points than to win a match if one wishes to be highly seeded, which strikes me as somewhat counterintuitive to my competitive sensibilities but probably reasonable. Has anyone calculated any sort of "sweet spot" for number of matches won without coopertition vs. matches lost with coopertition? Would it even be possible to calculate this?


It might be possible if you had a function that represented your scoring over time and the probability of balancing the bridge over time. Your expected win % and coopertition % for a given length of balancing could then be calculated.

Of course, the formula would vary from regional-to-regional (teams score different amounts at each regional) and match-to-match (it is probably best to spend more time balancing against weaker opponents.) I would use scouting, experience, and common sense instead of a formula.

[davidthefat]

Something that surprised me at San Diego was how different alliance selection ended up being in comparison to previous years, mostly because the coopertition bonus allows teams that cannot shoot baskets consistently to seed very high. In every previous regional that I have attended, the uberbots who could hang all the rings or score all the balls invariably seeded in the top eight, and alliance selection consisted of the 1st seed picking the 2nd seed, the 3rd seed becoming the 2nd seed and picking the new 3rd seed, and so on. At San Diego, no alliance's 2nd pick was from the top eight, since most of the really strong scorers had been too specialized towards shooting to do coopertition in many matches. This meant that the elimination alliances were more balanced than in previous years, and I did not get the impression that any one alliance was significantly stronger than the others.

Based on these observations and from looking at the team ranking charts, I have concluded that it may be more important to get coopertition points than to win a match if one wishes to be highly seeded, which strikes me as somewhat counterintuitive to my competitive sensibilities but probably reasonable. Has anyone calculated any sort of "sweet spot" for number of matches won without coopertition vs. matches lost with coopertition? Would it even be possible to calculate this?

On the whole, I really like Rebound Rumble. The qualification matches can be rather boring if everyone just stays on their own side, but the endgame is very tense and exciting, especially in the eliminations when an alliance goes for a three-bot balance and only makes it in the last few seconds. Near-realtime scoring is a very good thing, since I don't have to wait until the end of a match to see who actually won after penalties are calculated. I look forward to seeing how everyone adapts and adjusts in reaction to what we have learned this weekend.

I just thought that it was just the nature of San Diego, we seeded 4rth at SD last year, we never hung a single tube, just did the minibot.

Well, we had to take off the ball manipulator on our robot due to weight problem... I am fearful of the mediocre shooters converting into feeder bots and playing defense.

[Siri]

What I learned:
- As usual, Week 3 will be nothing like Week 1. I think this is exacerbated this year though, as originally teams had been very reluctant about defense given the number of safe zones. Even with two absolutely fantastic scorers (341 and 1218), shut-down defense let our alliance win by a wide margin in basically every elim match.
Stats:
- For all elimination matches combined, our alliance's average score difference was 49.2, all positive. This turns into 57.8 if you discount the QF in which 341 broke at the beginning--we won this by only 6 points. (They were up and running great next match without a timeout.) It drops to 44.3 if you ignore the (unsuccessful and I think unintentional) G25 red card our opposing alliance got in QF1-2 (their pre-card score was 29).
- For fender defense, the average score difference was 55 (47.8 without the red card, 71.3 without 341's breakdown, 61.7 without both). For the 2 QFs we played against an alliance of 2 dunkers, the average difference was 54.5 (adjusted 103, 40, 74 respectively). Actual scores were 41-47 (QF1-1) and 103-0 (QF1-2, pre-card 103 to 29).
- We also played fender defense in the semis against an alliance whose main offensive bot was a close scorer. This average score difference was 55.5, with nothing really out of the ordinary for which to adjust.
- We played what I like to call Inbounder Chicken in the Finals, blocking 2016's Inbounder throws and thereby hoarding balls on our scoring side and forcing 2016 (their long-range shooter) back to feed. (Also creates conditions for Key fouling, or Key-Ally mirror fouling which almost happened.) Based on the Finalist Alliances pre-finals teleop scores (average 15) as well as our alliance's same (average 30.7), blocking could have had a negative impact on the Finalists of approximately -6 and a positive impact on us of approximately +8.8, for a total differential difference of 15.2. Of course, there are also other factors, and granted we won by much more than 15 each match.
- I don't think Co-Op necessarily skews seeding too much, and this will likely decrease even more as teams get better at balancing. 341 and 1218 ranked 1st and 2nd whether sorted officially, by Teleop Points, by Teleop + Hybrid, by Teleop + Bridge, or by Teleop + Bridge + Hybrid. (Of course, they're also the 1st and 3rd OPRs in the country...) Overall it seemed that most strong teams realized the importance of Co-Op, and were ready to use it when beneficial (basically always).
Stats:
- In fact, at Horsham, sorting by TP+HP+BP versus sorting officially only produced a significant difference in 1 of the top 8 seeds, namely the 8th. 2234 would have been 30th, but had a CP of 8, matched only by 341.
- Overall, the rank difference averaged 7.7. 14 teams had a higher official ranking, 20 had lower, and 4 didn't move (seeds 1, 2, 3, and 29).
- There were two teams in the top 50% with 0 Coopertition Points: seed 5 and seed 12.
- Anecdontally, I actually found this to have a smaller impact than the minibot of last year. We ranked 2 of 56 (8-0-1) and won Philly that year when we would have ranked 18th (5-3-1) and probably not made it past quarterfinals without the minibot. Our estimated robot contribution was like 5. Of course, this is highly situational.


Exaclty how are they [fenderbots] being defending? Preventing? Pushing?In elims, we finished autonomous and raced (pre-agreed route) over the Barrier, down the Ally, and along the fender. We stuck to it (front and non-Ally side) basically the entire game. While shutting down two dunkers wasn't exactly easy, it was entirely doable and they even got in each other's way at the beginning. They scored 5 points total in Teleop the first match, and 6 the second match. Scoring from the side was equally blockable--no advantage there that I can see. You can't just sit there to block, but I didn't let my driver lose bumper contact with the fender until endgame.

From my viewpoint observing in the stands, the "quality" of the balls in play generally seemed to exhibit general wear and tear akin to what teams noticed during build season...

2018 (HH winning alliance, 2nd seed) had a unique system on their robot that measured the compression of the balls and adjusted their shooter accordingly.Agreed. It seems the competition balls are actually more consistent in manufacturing quality than the ones we received in the Kit or FIRST Choice. However, they are this manufacturing style was also the minority of what we were given in the aforementioned. As far as wear and tear, the MAR field at Hatboro-Horsham was only given 36 balls total, but they still managed to remove basically any ball missing more than say 1/2in^3 of foam from one place. I was pretty impressed, actually. Mostly just scuff lines. We were given some of the decommissioned balls (the winning alliance can't cut nets at MAR, so they did this instead--thanks), and they do get very beat.

Yes, 1218 used the "charminator" (like terminator) to measure ball squishiness. As their OPR and Blue Banner can attest, they're a fantastic shooter because of it. 341 took a different tactic, putting huge (I mean huge) backspin on the balls so they fall basically straight down once they hit the backboard no matter what.

David, a robot with the abilities you described has a certain niche imperative to winning this game: A feeder. If you could hold one to three balls, and then kick them back to your alliance's side, you effectively starve the opponents of balls to score with and feed your alliance. I know I'd want a feeder bot on my alliance, especially one that does the bridge well.I have to say, watch out for this. Having just won an event spending all of Finals blocking an Inbounder and all of Semis blocking a short lower scorer, I'd warn that unless you're a high kicker this is pretty easy to defend. It'll be especially true in elims, but if you're good I'd expect defense to pick up in quals at later weeks as well.

Sheet 1 of the attached worksheet has the elimination match score differentials for the Hatboro-Horsham's winning alliance and the pre-finals teleop estimates for the Impact of Inbounder Chicken. Sheet 2 has the seeding differences with and without Coopertition.