Regarding <R6>, <R9>, <R22>, Plastic Legality, and the New PET Sheets

VEX Robotics Competition Discussion VRC > Spin Up (22/23)
#1

Recently VEX released the “PET Sheet Variety Pack”, which contains in VEX’s words “Plastic sheets with “on-pitch” holes, can be used as a lightweight alternative to back your robot’s mechanisms. Includes 3 different sizes”. Until the Q&A opens, it remains unclear whether or not these parts will count against the plastic limit as described by <R​9>.

<R​9> states the following.
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<R​6> states this.

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On the surface, it would be fair to suggest that the new PET sheet variety pack does not count against the plastic limit. It is clearly a part meant for robot construction, and is directly listed as a V5 part. Nothing would suggest that it would count against the plastic limit in <R​9>. <R​6> would seem to imply that the only other rules that could affect part legality would apply to non-VEX V5 parts. The corollary on <R​6> states that “non-Robot products” are an exception to this, and this seems to be the only such exception that exists. The way the rules are written, anything with a “V5” label on the VEX website that is meant for robot construction is legal, and does not count against any plastic limit.

This interpretation is supported by the thinking of DRow, as he stated on Discord.
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<R​22> also seems to mean that any part derived from a VEX-legal structure part is also legal.

Now, up to this point, everything seems fairly cut-and-dry. It seems clear that the GDC intends for these new parts to be legal and not count against the plastic limit. As the rules are written, the fact that PET Sheet Variety Pack is listed as a V5 part makes it legal in unlimited amounts, and <R​22> makes it legal to cut or machine any shape out of them that it is physically possible. There don’t seem to be any discrepancies in the rule.

Now, I think everyone can agree that for the game rules to work they need to be applied consistently everywhere they apply. Which is why the existence of the following product poses some issues.

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These polycarbonate sheets are listed as V5 parts, and as the description states are “a great solution for making simple brackets”. This meets the established criteria for being legal in unlimited amounts: being listed as a V5 part, and being intended for robot construction.

Now, it is likely that the GDC intends these polycarbonate sheets to follow the plastic limits as described by <R​9>. Anything else would simply fail to make sense.

This leaves a discrepancy. If the PET Sheet Variety Pack is legal for use in unlimited amounts, as is intended, so must the Polycarbonate Sheets. Something isn’t right.

The “custom-made” test suggested by DRow doesn’t really work either, because cutting is already established as a legal process, so the act of cutting or machining can’t make it illegal.

As best I can think of them, the only resolutions to the problem are the following:

  1. Both the PET Sheet Variety Pack and the Polycarbonate Sheets count against the plastic limit
    a) This is undesirable because it goes against the letter of the rule in the game manual
  2. Neither the PET Sheet Variety Pack and the Polycarbonate Sheets count against the plastic limit
    a) This is “”“undesirable”"" because it would allow unlimited lexan, however I think this would be very funny and therefore support it as the answer to this problem
  3. The PET Sheet Variety Pack doesn’t count against the limit, but the Polycarbonate Sheets do
    a) This is undesirable because there is nothing in the rules to distinguish these two parts. Treating them differently without rules modification would not make sense, and would impeach any remaining credibility of the rules
  4. The Polycarbonate Sheets are de-listed as V5 parts, and instead left only on the VEXpro store
    a) This is probably the easiest solution that addresses all of the problems mentioned here
  5. Some other distinguishing factor between these parts or rule exist that I have missed
    a) If this is the case then I have embarrassed myself and apologize for wasting the forum’s server space

I plan to ask this on the Offical Q&A as soon as it opens, but until then I would be very interested to hear the opinions of the people here. I would also like to avoid “just look at <G​3>” as the answer to this question. No, <G​3> cannot be the answer to the question, because it is legitimately unclear how the rule applies. My interpretation of the rules would be that both of these items are legal for use in VRC in unlimited amounts.

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#2

<R9 uses the wording of “custom plastic.” So IMO, PET Sheets do not count towards the 12x24" plastic limit as they are a COTS part and not custom manufactured by a team. I would just cite common sense to back this up, but a red box under R9 confiming that PET sheets do not count towards the plastic limit would be nice.

#3

Yes, but as I discussed in my post, “custom plastic” is poorly defined. <R​22> clearly allows for the modification of parts, including by means of cutting.

How would cutting PET sheets differ legally from cutting 1/16 lexan sheets? I would argue that neither of these are truly “making custom parts” because they both derive from VEX-sold, V5-listed products.

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#4

I understand your point; but I think the best answer is for Vex to list the polycarbonate sheets as soley Vex Pro, GDC to make a better definition of custom plastic in R9, and for all the people that believe infinite polycarbonate is legal to use common sense.

#5

Again, I am fine with “common sense” as justification for certain things, but as the rules stand I do not believe you can “common sense-away” this problem. There is a legitimate rules discrepancy that reasonable people could interpret either way. It needs a real answer supported by language in the game manual.

I agree that the “correct” answer is to list the polycarb sheets as VEXpro only, but until then I simply do not see how you get past “they are v5 listed products meant for robot construction, so r6 makes them unconditionally legal”. As the rule currently stands, I would rule unlimited polycarbonate legal, provided it was physically from a sheet sold by VEX.

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#6

Additionally, if these do count against the limit, if one one was to use ANY of the PET Sheet Variety Pack, would <R​9> disallow any further plastic use? Because a paper-thin PET Sheet and a Lexan part are clearly two different materials, and couldn’t be cut from the same sheet.

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#7

According to R9 d, parts don’t have to literally be able to be cut from the same sheet, they just have to be theoretically able to nest within a 12x24 area, allowing teams to use different types and thickness of plastic on their robot.

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I agree with your previous points regarding whether v5 labeled polycarbonate sheets means that teams can use unlimited plastic. If the answer is no, then there is no reason the v5 labeled pet sheets shouldn’t count towards plastic limit either.

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#8

Not literally, but they do have to have been theoretically able to be cut from a single sheet. Different thicknesses haven’t been allowed in my experience.

3 Likes
#9

According to <R9b>, parts do not have to literally be cut from the same sheet. However, the team should be able to replace all their custom plastic parts from one 12" by 24" sheet. In my opinion, they should replace the wording of <R9b> with something like that.

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#10

Sort of older Q&As, but different thicknesses have been ruled legal in previous seasons. Now sure, Karthik has not been on the GDC for a while now, but I’d assume that the same mentality is shared amongst the current GDC members today (as long as you think of the limit as being 2D and not 3D).

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#11

There’s a specified max thickness you can have for your plastic.

As it is written and been explained, all your plastic parts, regardless of thickness have to fit in a 12x24 sheet. Don’t overcomplicate the rule m, use some common sense.

3 Likes
#12

Hi, based on your post, you must be new here.

There is a secret agenda by RECF, They are secret society made up of lawyers that foist off robots competing, but they are really trolling for “want to be lawyers” that have a tech background. They saw how in the 90’s that STEM and a financial interest could get new hires into quant-economics and the generation of crypto. They want to now leverage that to be in place for the upcoming “Crypto law suits” that are starting up, they are looking for a deep bench of players.

And silly us, we think it’s all about the robot.

13 Likes
#13

I looked at R6, R9 for a hour and a half last night and came to the conclusion that the Polycarbonate Sheet would fall under R9 because it is still technically a “custom-made part”. Vex motors are Legal vex parts under R6 but are limited to 8. Think of R9 like that.

#14

I’m going to attack this from a different angle. These are not comparable products. The PET sheets, by nature of their punched form, are a manufactured VEX part. Additionally, PET is usually really thin so these are not a structural element, but a durable and flexible cover for important open spots on a robot. They are quite small, the biggest sheet is 3"x6".

Lexan (and other legal plastics) is structural and despite being sold on the VEX site, is not a manufactured product. It has not been drilled, punched, cut, or otherwise modified other than sticking a label on it. It is raw material. Additionally, despite being labeled as “V5”, it doesn’t actually pop up in the V5 products section. You either have to go to the pro site or search for it by name.

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#15

Why does it matter whether Vex punches/drills/cuts something?

The rules are to be read as constraints. Pneumatic air tanks are restricted in quantity in spite of being otherwise legal.

The PET Sheet Variety Pack is of legal materiel, thickness, and dimension to satisfy the R9d requirements so long as its overall use on the robot conforms to R9b.

The fact that DRow, who is not on the GDC, agreed with Taran’s interpretation is not binding, nor necessarily even correct.

It’s a fair question for the Q&A, but I would be surprised if the product can be used in unlimited amounts.

2 Likes
#16

Check out sizes on product page:

  • (4) 2x12 PET Sheets
  • (4) 6x6 PET Sheets
  • (4) 6x12 PET Sheets

6"x12" is largest sheet.

or are the measurements in 1/2" increment - my bad - forgot that VIQC measure in holes.

1 Like
#17

I’ll preface this by saying that since this is a new product, it will hopefully pop up on the QA so we all can stop making assumptions.

Because its not custom any more. R9 is concerned with “custom plastic”.

If you’ll allow me to be cynical for a moment: VEX is a business and as such primarily cares about making money. Everything else is secondary (you, me, the competition, etc.). I would be shocked if the PET sheets counted against the R9 limit by economics alone. PET is dirt cheap (which is why its an environmental concern), and the profit on the PET sheet bundle is insane. If a team wants to buy a bunch of them, bolt them together, and slap them on a robot, VEX will likely oblige. I’ll also say that while the thickness is unlisted, the IQ part calls for the sheet attachment studs which have a max thickness of 0.010", so that’s probably a good upper bound on the V5 sheets. To me this really supports the “these are not comparable products” argument. In my mind this is really just wire protection, anything that thin is going to have limited uses.

“But Blinken, they also sell polycarb sheets. Ha, checkmate!” Yes, they do sell those, and they mark them up too. The catch is that you don’t have to buy it from VEX. You can go to McMaster-Carr or your local Ace Hardware and buy the same stuff.

1 Like
#18

So if you were to modify one of the PET sheets would it suddenly be covered by R9? Or if you were to not at all modify a sheet of the polycarb sold specifically by vex (because most functionally identical parts to vex products are no longer legal), would it then not count towards the polycarb limit?

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#19

Well, if you use different types of plastic, it will not literally be able to be cut from the same sheet. However if it still can all nest within a 12x24 area, then it’s still legal. At least that’s how it’s always been ruled in the past.

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#20

While I’ve not measure them, I can confirm that they are not very rigid at all, and definitely not a substitute for the polycarb sheets.

Until the Q&A addresses, this, we’ll have to agree to disagree.