Why is 3D printing still not legal in VRC?

I’m just curious to see other competitors’ and possibly VEX/RECF employees’ opinions on this issue.

At this point I see no reason why 3D printing should be disallowed by VEX VRC. I understand that in the past it may have been seen as cost prohibitive but now a low-tier printer like an Ender 3 is as inexpensive as a small order of VEX parts. Other than that it seems just like it is disallowed by VEX purely for profit.

If I worked for VEX and wanted to implement 3D printing, I feel a good middle ground would be a system very similar to how the custom polycarbonate/Delrin budget currently works, where each team would be allowed a certain mass or volume of 3D printed parts while prohibiting teams from fully 3D printing their robots like some VEX U teams or just replacing the need to buy gears from VEX.

Curious to hear y’all’s thoughts.


Perhaps because 3D parts would allow for teams with access to better filament to get much better weight optimization. Better filament usually isn’t too much denser and yet can handle torque quite a bit better, meaning that small lifts and gears (esp the 24T gear, which doesn’t have a plastic variant) could be entirely 3D printed, saving a lot of weight.


Beating a dead horse here is probably not best use of time.

I would imaging this topic was likely brought up in the Student Advisory Board, and other channels.

When the GDC decides to allow it, it will be in the Game Manual (which will be out shortly).


Hey, welcome back. You should do a search and find the really long thread about 3D printing from spring 22. It ends in June of 22 when I reported back the results from the Event Partner meeting. I think you’ll find all the info you want in that thread.


3D-Printing advocate here.

Draw your own conclusion from 2 years ago, but I think the pro-printing crowd won the debate. Unfortunately the anti-printing crowd was the RECF and were unmoved, so winning the debate did not change their minds.

I proposed a few 3D printed parts with a given maximum dimension. Like something you could measure with a caliper. This makes it easy to measure and enforce.


1: it would mean that there’s a significant advantage for smaller/poorer schools. Not having a 3D printer = having a worse experience (probably)
VEX U allows it because most universities with the program will have them, as they are often high-funded.
2: VEX wants to make money selling the parts.

Even if the printer is inexpensive, school budgets can be weird.

In my opinion, it’s a skill gap that Vex doesn’t want to introduce. Right now, what sets the good and great teams apart is the use of cut lexan/delrin. If you were to introduce 3D printing, while more accessible than before, it would still benefit the top teams.

You could also make the argument that it would be exceedingly hard to determine if a 3D printed part is in the desired limit. How could your regulate infil, or using different filaments? Would the cheap school teams use PLA while the top teams use NylonX? If they were to regulate types of filament how would you check that? Would most teams cheat?

Knowing Vex, this would take away from sales- mostly gears in my opinion. While Vex has hinted at allowing printing, due to the culture displayed by the company, I’m pessimistic that it will happen.


I think 3d printing could be really cool and offer a bunch of creative desighn solutions but there is also that aspect of taking parts that are given to you and making the best robot possible from these specific parts that really gets the creative juices flowwing. I also thingk that ve is hesitent to allow 3d printed parts because it could increase the gap even further between high, middle and low budjet teams. already with the release of flex wheels and pneumatics the gap has widedn and allowing 3d printed parts would just widen the gap even further.


Here we go again…

VRC uses a certain set of allowable parts.
While it is impossible to create a completely fair and even playing ground, having a set list of legal parts is a very good way to limit how much the quantity and quality of resources affects individual teams.
Sure, you can buy more aluminum C channel, but no matter how much sheet metal you buy, it will never ever magically gain new functionality.

Additionally, adding any sort of limitations to 3D printed parts rules is near impossible to referee.

IMHO, 3D printing will become legal when you can no longer say; “Man, if I could use 3D printed parts, my robot would be so much better.”

SIDOTI PREDICTS: There will be a water game in VRC before 3D printing becomes legal.


Because not all teams can afford it. 3D printing is much more complicated than buying a 200-dollar printer and letting it run. One argument against plastic, when it came out, was that teams who had CNC or Lazer cutters would have better plastic parts. Different 3d printers are better than others, so teams with a worse printer couldn’t make as fine parts as other teams. 3D printers break often. Professional companies have 10 printers because 8 of them are broken at a time, so teams might have to buy several. Expensive printers break less, so larger teams wouldn’t have to spend as much time fixing them. Vex shouldn’t give teams an advantage because they spend money. Winners should be determined by skill and work, not funding. Also, where does regulation begin? If it is a volume calculation, would teams have to show a CAD or take off all their parts for inspection?


In this example though, teams could just mill out these gears to lighten them and a milling machine is much more expensive than a 3d printer.

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As far as more expensive printers, in my experience tuning has a lot more to do with the quality of prints than the price of the printer. Normally more expensive printers have nice to haves like auto bed leveling that don’t increase quality. As far as proof a cad model would be exactly what I suggest the same as a lexan sheet.


Let’s clarify a couple things: VEX is a company that makes educational supplies, the rules for the game are from REC Foundation. REC foundation neither gains nor loses money from VEX part sales. Furthermore, although competition robotics participants are quite vocal, the sale of competition gears and other plastic parts would likely be insignificant compared to the total education sales of VEX Robotics. The “money” argument just doesn’t fly, a successful justification for/against 3d printing must be philosophical, not monetary.

Gears would be some of the worst parts to try and 3d print! Duplicate “form” does not equal duplicate “function.” Injection molding makes a product with greater strength, and especially greater toughness, than hobby-sized 3d printers. Additionally, the fine involute tooth form of VEX-sized gears cannot be reproduced well on hobby-printers. But printers and supplies keep improving, and teams, if allowed to used 3d printed parts, will discover (hopefully in early-season events) whether or not their parts are strong/tough enough for competition, as U-teams have been doing for years.

Parts that make sense for 3d printing include bearing flats and especially flex-wheel inserts. As a non-competitor advisor to a U-team who keeps our VRC teams supplied with parts as well, I remain ambivalent to 3d printing in VRC, and will go along with whatever the game manual states, hoping this argument shows up on the forums only once a year.


The GDC makes the rules which have people from both RECF and IFI. And the vex employees want you to buy vex gears.

Have have seen vex U teams (namely WPI) use custom gears with success. They seem to use a much larger pitch on the gears.


A drop in the bucket for VEX/IFI…my point is that the monetary argument is useless. If you want to successfully argue for 3D printing, you must do it some other way.

Yes, my point exactly: without redesign, you can’t print successful gear of the same size as a VEX gear on a hobby-printer.


Wow. This is uninformed. Most good Vex U teams use custom gears to achieve optimal drive ratios.



OK, my last post about this because I don’t really care one way or the other…

Yes, I know that many (not most) U-teams print gears with specific ratios. But you miss my point (or I didn’t make it well at first). If a MS/HS team takes the .stp files from the VEX website and prints those gears on a “hobby-printer” the gears will likely not work well, as the hobby printer generally lacks the capability and resolution for the fine detail. U-teams usually have access to better printers and materials, and as you said, generally redesign the gears which is something a MS/HS team might not do.


Thanks @AperatureLabs for the post to the orginal topic!

Hard to think it was 2021. But the conversation with the EP’s was last summer (2022) and the general thought was the same.

I am sad to think that gears are the things people want to print. Gears are constrained by the 1/2" hole distance and the existing gear geometry.


Things like the hybrid gears are pretty cool Hybrid Gear Pack - VEX Robotics so those could be fun to 3D print. Or the GDC could go “legal part” and for $10 I have a stack of them.

On the other hand, outside the box designs would be cool. These elliptical gears have a place Cunningham Industries, Inc. in this year to trigger the disk shout, these would have been awesome.

I’ve seen so many cool mounting parts show up in the annual on-line competitions. I’d love to see the people that give prizes for these parts to say “Hey, we made a x,000 of them, come buy them” (Etsy for legal parts). I think these connection parts are the sweet spot for 3D printing. A replacement for taking 4 collars, an axle and a handful of standoffs with the threaded rod to make a 8-way connection point.

But as noted in the last note I wrote in the 2021 thread, someone(s) need to build a business case for why 3D prints should be a thing in VRC. Not me, I’m done, put away my lance, helmet and the donkey is out back eating grass. But feel free to tilt at this windmill.

Foster predicts that @Sidoti will be close, 3D printed parts will not be allowed until after the SECOND water game.


Right, and I did doesn’t at all seam like the kind of company to squeeze out every last parent from their consumers.

I don’t think anyone was talking about doing this.

Almost as if you could make you own gears without these constraints…


I do this regularly for our VEXU robot and have no problems. I have a high-end hobbyist printer (Prusa MK3, about $900 when I purchased it a few years back), but have seen similar performance on cheaper printers that were well-tuned. I’ve seen Ender 3’s on sale for $100 in the past.

I think it’s perfectly reasonable to enforce a volume limit or even have the option to trade the current plastic allotment for some quantity of 3D printed parts. Complicated parts take time to develop and get right, so “going custom” is not always a good thing. It isn’t particularly difficult to add some tradeoff into the manual so that teams can’t just “pay-to-win.” Would you trade unlimited 3D printed parts for one motor off your motor limit? How about two? This is a totally reasonable approach to keep the playing field level.

I like incorporating 3D printing because requires students to actually use CAD software and start to think about manufacturing considerations. These concepts are essential in industry and almost completely unnecessary to be a high performing VRC team. I think it acts as a good incentive for students to learn new things and grow. A few years down the line when 3D printers have further expanded into school districts, I think it’s very feasible to introduce it into VRC.

I’m not too invested in this argument overall, but as a fun aside, here is a component printed on that same hobbyist printer that runs on our current VEXU robot. It works fine. It certainly didn’t work on the first time, but you can’t be an engineer without learning about tolerancing. ¯\_(ツ)_/¯