Robot in 3 Days Team PRi3D of the North - '21

Hello everyone!

We are PRi3D of the North, an Ri3D team at the University of North Dakota. This is our second year as a Robot in 3 Days team and we are excited to be back! Check out our social media for daily updates and watch for links to our YouTube videos!

Social Media:
Facebook Page: PRi3D of the North
Instagram: @pri3dofthenorth
Twitter: @Pri3dN

If you want to connect with us, be sure to check out our social media or send us an email at!

Best of luck in the upcoming season!


Very glad to see the harpoon climber. We did some prototypes like that based on the 118 StrongHold design. We had trouble getting it to work but we had a lot of fun doing it. I look forward to seeing how you guys get it to work. Keep up the good work.

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Here’s our 2021 Robot in 3 Days robot!

DISCLAIMER! Given the fact that we only had 72 hours to build, we were unable to get most of our pieces in working order. However, here is the robot completely put together and driving around, with close-ups of our mechanisms. Enjoy!


The robot looks very ambitious! With more time, it certainly could have the ability to check a lot of boxes. I do have to say, when I think about (what I believe to be) the mission of Ri3D teams, I struggle to understand some of the choices you guys made. I found your disclaimer to be a bit ironic, as over-ambition tends to be the Achilles heel for many many teams every season, with the robot subsequently not getting “done”.

With what is happening in the 2021 season, I was hoping for Ri3D teams to show an early preview of some of the skills challenges. We’re completely unable to meet in person at the moment, so seeing a robot run the Barrel Run course and get some benchmark times would have been huge for us, as just 1 example. Understanding how many shots a robot can reasonably take in 1 minute with only 3 game pieces another. Instead we see WCDs, Turreted Shooters, WoDs and Harpoon Climbers - all of which I would not recommend to inexperienced teams.

All in all, I think FRCers can always appreciate genuine effort and blood/sweat/tears put in, so I apologize for being a bit of a downer with this comment. I’m just hoping by adding some of my perspective you guys can incorporate it into future efforts.


Hey Brandon, I understand your concerns, but some are without context that we may have failed to effectively supply. Our build and analysis started on Friday the 8th (24 hours before the 2021 reveal). We started a day early due to classes at our university resuming on Tuesday. Had we not started on Friday, rather than Saturday, we would have been forced out of our workspace prematurely, as our build would have gone into Tuesday, instead of Monday (as well as interfering with many members’ classes). With this in mind, we decided on Friday to build a robot to showcase alternative mechanism designs that may be useful to different teams. The idea behind it being that we wanted to build a better Ri3D robot than last year so that teams that are looking for ways to improve their 2020 robots would have some content to watch for this season. On Friday, we determined that the biggest changes that teams with tall bots would likely be trying to do is turn their current robot design into a short bot after seeing how effective low bots were in the first few weeks of competition last season. With this in mind, we set out to find out how to build the simplest, “easiest,” effective short bot to play the 2020 game. This is especially evident in our turret design.

Our turret uses the same shooter as our 2020 Ri3D bot mounted to a simple $20 lazy Susan bearing from amazon and driven by a bag motor and a compliant wheel on the OD of the bearing. Paired with a limelight, this gives you a simple targeting mechanism with minimal effort and modifications to most peoples’ current designs. Is this the “right” way to do it? No, of course not, chain and sprocket or belt and pully would be much more reliable and much more effective, but it would also require much more engineering and access to machines that most teams do not have. This is the reason we went “simple” with this design. Electing to showcase how a team could get “up and running” with a basic turret design without access to any CNC or 3D printing machines.

We watched the reveal, like many FRC teams, and determined that our current path of showcasing mechanisms over covering the “new” challenge was the correct one in our case. We were already deep in the build and did not feel that pivoting our priorities at that point would be wise for our team (there are many other teams that may cover these areas). We have not ruled out making further videos on these subjects and merely ruled out making these videos during our last valuable 48 hours of building. Now that the build has been “completed,” we may decide to go back and address these challenges if there is enough demand for this type of content.

When we went into discussion on how to make a climber for a short bot, we ran into some barriers. Ultimately, we wanted to get up to any level on the bar without having to make any sort of complicated lifting mechanism. We ended up with a couple of enthusiastic and passionate team members who suggested a 2016 118 style grappling hook with a camera mounted at the base of the hook for alignment. This approach has the benefit of being light weight and effective but has the downside of being single use. It is ultimately up to teams to decide if that is a risk they are willing to take. In my opinion, if you make a reliable mechanism and have good drivers that get adequate practice deploying the “harpoon,” it wouldn’t be that bad of an idea.

Our intake was a three-bar intake. This was a simple and effective design that worked well with our robot’s overall design and layout. I believe that many teams may benefit from a lightweight, reliable design like this one. If they are looking to cut weight and would like to get rid of a heavy intake mechanism that they may already have, this is a good option.

Our WoD style hopper was done with the idea that it would be a quick and easy build that would allow us to spend most of our time on the component integration aspect of this design. In the end, this was not a success as we struggled to implement the design how we initially planed (with the turret in the center of the WoD mech, fed by an omni wheel running over the top of the balls). We ended up concluding that rotary hoppers are definitely a good idea, and with enough work put into integration and problem solving, they can be made into successful designs, for sure. Ours was just not a very good example of one, at all, and I will be the first to admit that.

Yes, we did a WCD drivetrain and yes, I wouldn’t have it any other way. Let me ask. When is the last time you used the Andymark KoP chassis? Probably never, if you are going to be honest. Why is this? Why do you rarely see high level teams using the KoP chassis? BECAUSE IT SUCKS! It is inferior to a West Coast Drive in every measurable category. Does anyone remember the 2016 game where FIRST literally designed an obstacle that could trap literally any robot using to KoP chassis? The WCD is lighter, cheaper, simpler, more durable, easier to repair at competition, lower profile, more powerful, and more customizable just to name a few. Every team should do a WCD in my opinion, it damn near pays for itself. Go out to name a few. All a team has to do is fundraise, get sponsors and save up for one year and you can get one yourself for around $1,000, depending on the configuration you want. Then you know what you do, you deny the KOP chassis before kickoff and get the $450 Andymark voucher for the current season, and every FRC season after that. Unlike the Andymark drive base, by the end of the season, your WCD will still be roughly 95% COTS items, with the only thing you will need to buy new is standard 1x2 aluminum box tubing and possibly some new wheels if you wore through yours at comp. After the first year, you are GETTING PAID TO USE A SUPERIOR DRIVETRAIN. I am dumbfounded trying to understand why anyone would discourage the use of a WCD. As a testament to how easy it is to assemble, I had two of our team members that were completely new to any thing FRC or robotics related assemble the whole thing on the first day this year. With one team member stating “it’s literally adult LEGOs,” you just have to follow the instructions on the Vex website.

Now I know this may come off as a curse word to some, but my philosophy in FRC has always been “do everything and do everything well”. If you want to “do everything and do everything well,” you need to be willing to put in the “blood sweat and tears,” as you say. With any team perspective is key, understanding the workload your team can effectively handle in any given season is easily one of the hardest problems team leadership encounter every season. Our goal with this robot was simply to showcase how to build on last year’s design and push your team to an arguably more competitive state.

One thing I strongly disagree with is telling teams that they cannot have creative or ambitious designs simply because they are a rookie team, inexperienced, poorly funded, etc. This rhetoric is so toxically present on this platform and throughout FRC it makes me sick, and it has got to stop. If a team is willing to put in the work, (and I mean a lot of work) they can build ambitious robots that compete at a high level. If you have the manpower and determination, you can learn and do most whatever you want in this world, even outside of FRC, and that’s a damn fact. It bothered me to no end when I was on WARPSPEED and they told me “you can’t start a Week 0 event and robotics hub, build a WCD for the first time, Powder coat your robot for the first time, rebrand the team, and fundraise 2X the amount of money as any previous season, all in the same year” then guess what, we did, and we did it all well, so well in fact that we were first time alliance captains in Duluth that year. The fact of the matter is if you have the drive, determination and willingness to sacrifice a good number of your waking hours to make your dreams and designs come true, they can, and they most likely will.

The point of Ri3D is to showcase what 3 days of hard work and dedication can give you. I’m not saying our robot design is perfect, it’s far from it, but what Ri3D robot is? If you could build a perfectly functioning robot in three days everyone would be building their robots over a long weekend. Obviously with a week of testing, tweaking, and refining this robot could be a decent competitor at a 2021 FRC competition (something that has not yet been ruled out for the 2021 season). Therefore, out of all of us here I believe you are really the one that “struggles to understand the mission of Ri3D” and not anyone on my team. The mission is to showcase ideas, not make “recommended robots” or to tell teams how they should build their robots. It is ultimately up to the FRC team members to determine what is best for their team and how much time and effort they are willing to put in to make a design work. The last things teams should do is go on Chief Delphi to have all the “low number know it all’s” tell them what they can’t do and “how to build a robot for inexperienced teams” while they themselves go have success building ambitious and complicated robots and have much more success doing it. At best, this behavior is done out of ignorance of other teams’ ability to push themselves and at worst its tyrannist act to degrade teams deemed “lower than ones own” in an attempt to keep them designing inferior robots to reduce high level competition. Either way, it is an absolute disgrace.

Derrick Seubert

President- PRi3D of the North

Mentor- FRC Team 8188 Grand Force

Alumni- FRC Team 4239 WARPSPEED

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If a team isn’t able to machine a reliable turret, chances are they’re going to have a way better time at competition by just … not doing a turret .

Last season.

Because they have the manpower to devote to designing a chassis that integrates perfectly with their existing designs, and machine time is negligible for them. That’s why you’ll see some high-level teams with sheet metal drivebases that are very similar to the KOP drive, but altered slightly to package neater (see: 6328). Also, 3940 and 7457 are both amazing robots that used the KOP chassis this year.

This is just blatantly false.

Also why FIRST hasn’t done anything similar since, because they realized the game was awful for teams using the KOP chassis

Sure, by a small margin that doesn’t matter for most low-resource teams

You quote a figure of $1000 for a WCD, while the KOP chassis is $650 if you buy it straight from AM (free if you get it in the kit of parts)

They’re both just gearboxes spinning wheels with belts/chains – there isn’t much complexity to either, though the execution complexity is way less with the KOP chassis, since it comes with center distances already worked out, and it’s a matter of following a guide to assemble it.

This one’s just false. The KOP chassis is a beast, and can take a serious beating.

If you assemble the KOP drivebase right, you should never need to repair it, since it shields all the internals, and by making a few simple modifications you can make wheel swaps and repairs in under 10 seconds (vs the 30 seconds usually).

Sure, but it doesn’t really matter in most applications

Power is a mathematical value that comes from the motors you have on your input. 4 CIMs on a WCD has the exact same power as 4 CIMs on a kitbot.

Again, in what universe would it be worth the time for a low-resource team to spend a week tinkering with their drivebase instead of focusing on building functional scoring mechanisms.

No, a curse word would be something off this list

This is the absolute worst advice I would ever give to a rookie team. I wish someone had told us to not try to be creative or do too much our rookie year (2019). We ended our season not making eliminations and ending all 3 competitions with a broken robot because we tried a funky motor-on-arm passthrough design when we didn’t have the knowledge required, while we would have easily made semifinals consistently if we had just done an everybot and focused on iterating a climber.

Before you say we didn’t put in the work – I was consistently putting 40-50 hours a week into robotics, to the point where I was physically ill at our first competition, but between managing our team administratively (we had no mentors), doing a bulk of our CAD and a solid amount of manufacturing, and writing a good chunk of code, we simply didn’t have the resources to be throwing at trying to design an arm that had slightly more functionality than the everybot (by virtue of being able to complete the first level of the rocket). I’m just thankful I took people’s advice and used the KOP chassis, otherwise, we’d have definitely struggled to even move at all.

Yes, which is precisely why teams should /not/ try to “do everything and do everything well”.

brb becoming a pro nba player in one year with no prior basketball experience.

Sure, teams can build up to competitiveness with a lot of work (our robot this year is capable of “doing everything”), but it takes /time/ to build that experience needed to design and build a competitive robot that does everything.

Or, hypothetically, it’s a good-faith action by teams who have been in the position of not being good and have made the same mistakes, and want to see other teams grow and succeed.

As someone who went unpicked for my first 3 years of competition robotics, I don’t see struggling teams as “lower”, and my purpose in telling them to limit their scope is never to degrade them, but rather to prevent them from trying and failing to design a robot beyond their means, since I know what it’s like to sacrifice your sanity trying to get a decent robot together only to watch it completely implode at a competition, and I wouldn’t wish it on anyone. I get that people shouldn’t underestimate other teams, but chances are the people who usually send that type of feedback to teams have seen hundreds of other robots, and have a much better feel for what teams can do than what some rookie who’s never built a robot before thinks they’re capable of.


Well that’s a slanderous take :angry:

Look, I’m sympathetic to the idea that FIRST designs games that require complicated robots that “do everything” in order to win. That’s maybe something for the game design challenge entries to look at. But in general, teams are going to have a better season if they succeed at a perfecting a smaller amount of tasks, than if they fail at trying to do everything. To illustrate, we’ve all seen teams show up to competition with a half finished robot. Conversely, we’ve also seen well built 118 “Everybots” make it to finals.

Moreover, I reject your suggestion that the KOP chassis isn’t any good. We picked up a few banners with it in our first two years. Teams have won Einstein with KOP chassis! We love the Versa Chassis too, but there’s no strong argument that one is “inferior”, especially in the context of giving advice to teams playing the Infinite Recharge at Home Skills Challenges.

I get that you had different aims with your Ri3D project. “Showcasing Ideas” is fine - I love teams that pull off crazy things like suction climbers last year, or robots entirely built from wood or 3D prints. I really like your simple designs for the intake and shooter. You can be proud of pulling those off in 3 days for sure. Brandon was just disappointed that you used your platform to work on game challenges (like climbing) that are less useful to your viewers in 2021 than in 2020.

Finally, I guarantee no one is telling teams to build simple robots out of malice! Everyone here loves when teams are successful. You should reconsider that accusation.


How can you possibly give this advice to low resource teams!

I don’t think I have ever disagreed with post from a RI3D team more!

I beg anyone who is trying to learn that is reading this please ignore this entire post.


Man, I don’t know if I’ve ever missed the Negative Rep button more


Dude, all I can tell you is, you still have a lot to learn.


When Ri3D was originally announced in December 2012, the majority of the announcement was focused on helping less experienced teams:

We could help all of those teams out there who don’t have experienced mentors to help quickly prototype parts and figure out the basics of an FRC bot. Compressing the entire build season into 3 days will give these teams an insight that they might not get until the season is over, thus making them more competitive

Since the goal was the create a fully functional robot in 3 days, a simpler, less ambitious design had to be selected, making it a great example for low resource teams to implement and a target for middle resource teams to exceed.

I think some of the initial rub comes from this differing views on the goals or mission of Ri3D. I have no problem if groups want to build ambitious, Einstein level robots in 3 days or 6 weeks. But, to do that under the “Robot in 3 Days” / “Ri3D” name, it’s going to raise some eyebrows since those names mean something different to majority of people, especially those who were around in the early days of Ri3D.


There are a lot of sentences in your post that I want to pick out and reply to individually but I don’t have the time so I’m going to grab the worst couple (above) and use them.

Opinions like this about the KOP chassis fly directly in the face of the purpose of Ri3D and make me wish there were an advisory committee to decide on which teams/individuals are allowed to participate in the Ri3D program.

You cobbled together a robot in 72 hours and gave us a ~2 minute video that didn’t show a single component functioning as it would on the field, other than the WCD driving around on a flat floor. There was no ball collection, no indexing, no ball shooting/scoring.

If your team (or a team who copied this design) were to show up to an actual event with this robot, you’d be utterly embarrassed by any number of teams using the AM14U kitbot and picking one or two game objectives to focus on, rather than trying to “do everything and do it well” as you say is so critical.


I was with you until you started trashing the KOP chassis. I don’t like being gatekeepy about what Ri3D should be or who should do it, but encouraging new teams to skip out on a perfectly reasonable drivetrain is irresponsible if you’re intending to be a good resource for teams. We’ve been doing custom drivetrains for a while now, and to be honest, I don’t think I can name a single time we couldn’t have made a modified KOP chassis work instead. This is including at least two WCD-like drivetrains, one of which we would have rather had the KOP chassis since it gave us so much trouble!

If you want to try to build something insanely competitive, that’s fine. But please understand that you can’t present it as something any team can and should be doing.


Here’s something you should read.

Oh, and while I’m here:

We already know what an Infinite Recharge robot looks like. We had two weeks of competition, saw a few thousand finished designs, had a group of teams in the #openalliance show their whole processes, and already had an Ri3D.

The value in Ri3D this year would have been in showing off IR@home challenges, which require some different design tradeoffs. It would be really good to see some runs of the various challenges to get a feel for what scores are going to look like and where we’re probably going to run into issues.


Yes. Very well. I saw many custom drivetrains trapped on those same obstacles. Perhaps you should consider why the people on 118 chose to base their Everybot concept on the KOP chassis, year after year. They are one of the groups that are most frequently (but not always) successful at “doing everything well”.

One of the purposes of this program is to teach critical thinking and how to use (ALL) relevant facts to make good quality decisions. If your group is cherry picking the facts to make a decision, it will be a poor quality decision.

So is the result of your efforts competitive?

History has shown that most teams, regardless of their resources and how much blood sweat and tears they put in will not be able to do everything in an effective and worthwhile way.

Perhaps you should explain clearly what you mean “do everything and do everything well”. Do you mean having a mechanism installed on your robot that looks like it is intended to accomplish some game objectives but does not actually function in an effective and competitive manner? Do you mean having a mechanism installed on your robot that actually accomplishes some game objectives in and effective and competitive manner?

Every year, I see many mid-level teams as well as quite a few high-level teams get too ambitious and fail. While failure is a necessary part of learning, the failure that comes with grossly over-reaching, as you advocate, will lead to a situation where no learning occurs since the team was so far beyond their capabilities that they have no clue why they failed.


Have you ever stopped to consider that quite a few of us disgraceful mentors on low number know it all teams actually spent a bunch of our child hood or mentor life on low resource teams? And the reason you hear so many of these concepts repeated to lower resource teams is because we have had first hand experience on how to do things the wrong way on said teams?


Not gonna say much but this video might be of good use to OP:



Look, I’ve been in your shoes. From 2015 to 2018 I was one of the leads for Snow Problem Ri3D. I went through our ups and our downs.

In 2017, following months of seeing snide comments about Ri3D on here, I made this thread. Nominally it was to ask people what kind of documentation they preferred, but really it was because based on everything I was seeing, we didn’t have a good reputation.

Regardless of whether I personally disagreed with some of the complaints (and, honestly, I did), the end result was that we weren’t achieving our goals. It’s rough to look back at three years of work and say “man, we messed up,” but that thread, and some of the comments in it, I think were a turning point for Snow Problem going into 2018 (and, while I wasn’t involved in 2019 or 2020, I hope they informed those efforts). We retooled in 2018 to focus on documentation that people said was more useful, and we intentionally avoided doing some of the things that people said were annoying (we kept the blinky lights because our videographer has to have some fun).

One of the most important parts of creating content for our FRC community is that we have a huge amount of passionate people who will help you if you ask for it. It’s extremely rare for people to come in with malice to a thread like this-- what often gets read as malice is disappointment, disagreement, or a strong reaction to someone who doesn’t really seem to know what they’re talking about. Part of the reason you’re going to get jumped on for a response like this is because so many people here are genuinely passionate about improving the experience of teams who aren’t as well resourced or haven’t experienced as much competitive success. A lot of us, as Rohit mentioned, have a long history of various experiences in the competition. Many of the times when we advise building simpler robots, it’s because we didn’t do that and got that incredible privilege of spending an entire season working on a robot that can only be viewed as a mistake in retrospect.

I hope you can give some of the advice you’ve gotten here some thought, and expand your mind to look at it from a different perspective. Good luck in your future Ri3D or other FRC-related endeavors.


Derrick - I don’t know you, your teams or your background. You don’t know mine. I was super respectful in raising these questions to you and your team - if you want to half-call me a tyrant engaged in some conspiracy to prop my own team up…go right ahead, but I promise you look worse in this exchange.

I said nothing about creativity in my statement, nor any of the stuff you mentioned after it. Me and my teams have put a countless amount of energy and time into directly helping teams of all backgrounds get better, become more sustainable, you name it. You don’t know anything about the experience backing my questions.

You said a bunch of things to justify the decisions and effort you all put in. I respect and appreciate the response and the thought behind it. I don’t agree with most of it, but I’m happy to continue to have a respectful conversation about it. To do that though, I need to add some information to this thread.

I clearly struck a nerve in asking these questions. The reason I even sent my original message was because I have been someone just like you, trying to make a name for myself and my team. Trying to show teams there is a different “way” to do things (PS- there’s not a “way” there’s a million ways). I butted heads with a ton of people along the way, and felt very similarly as you do to advice I was getting from “low team numbers”.

Because of that, I know much of what I say will not actually be taken to heart, and that is ok. I do know though, that if you stick with FRC, you’ll likely remember threads like this and conversations you’ve had with folks as you grow.

If you want to talk more about your technical choices, Ri3D philosophy, my background or yours, I’m happy to do so here, on a PM or on a video chat. I’m putting the ball in your court though to show you’re capable of having that type of conversation in a beneficial way.


Not going to parrot anything anyone else has said here. I just find a special irony in claiming that a custom WCD is better than a KOP chassis in every way, then proceeding to make a custom turret with a lazy susan citing low-resource teams instead of simply buying a Greyt turret.

115 had arguably its worst 4 years of competition when I was on the team. Overreaching consistently led to our poor performance on the field. Taking a year to go simple and build your basics will allow you to excel in future years; 1072’s 2017 robot was dead simple, and we built on that to make increasingly complex robots in the years that followed (for better for for worse :P).