Field markers for skills challenge

I recently came up with a good option for markers for our skills challenges. I started with a ball from 2017, the wiffel balls, cut out an area big enough for a pool noodle, and put a bag of damp sand in the bottom. Then a section of pool noodle sticking out of the top makes a self righting marker.


Does this fit within the updated rules for markers?

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For competition (per the manual), the markers are required to have “a minimal cross section of 2.5 in (~63 mm) wide by 2.5 in (~63 mm) deep and at least 5 in (~127 mm) tall.” It is not clear whether the 2.5" wide/deep dimension is max, min or nominal. but the 5" diameter 2017 fuel whiffle ball is probably too big. These markers would certainly work great for practice sessions.

FTC has utilized smaller white whiffle balls in their game many times in the past (most recently in the 2018-2019 game, Rover Ruckus) which many FTC teams would like still have haunting the corners of their build spaces. Those balls are 2.85" diameter which might be considered to be within an acceptable tolerance of 2.5" to be used for markers. This idea of self-righting marker could easily be adapted for that ball and some smaller item similar to a pool noodle for the “flag”.

I’m guessing that the GDC had in mind using 5-6" lengths of pool noodles just sitting endwise on the floor for these markers. There are ways to secure them to the floor using an upright spring or a shock cord stretched through the middle such that they would still be self righting.


Too bad these are not a whole lot cheaper…

I might be missing something here, but I assume the word “minimal” indicates the dimensions represent the smallest possible marker. Bigger ones are acceptable (and, per the spirit of the rules should be, since they’d make the path harder)?

I’m still advocating to 3d print out pylons of those exact minimum dimensions to make the challenge as easy as possible.


Well, that was not how I read the word “minimal” but you may be correct.

I had assumed that the word minimal was meant to say that they would be small enough to take up negligible space on the field. Thus, the dimensions listed could have been interpreted to be a max dimension or a nominal dimension with a relatively small tolerance.

I would have thought that if they wanted to specify that the markers should be larger than 2.5" x 2.5" x 5" that they would have used the phrases “at least” or “having a minimum dimension of” or something like that. They did use the term “at least” for the height.

But then, could we use nice big traffic cones with reflective tape on them?

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I think there is considerable remaining ambiguity with game markers-- our interpretation was that the dimensions given represented the minimum possible size, based on the examples (traffic cones, a soda bottle duct taped to a steel weight) that they gave. A remaining question I have, for example, is whether essentially you need something larger than a 2.5"x5" circular cylinder or whether an object 5" tall with a maximum 2.5" circular cross-section is allowable.

Lots of fun with this one.

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I can imagine cheesy markers for the Bounce path, where you are allowed to have a different marker for the endpoints you need to touch.
For example, a 5 foot wide marker that is impossible to miss, and cuts out about 30 feet of path to cover. Legal per the written rules? Maybe.
Does it pass the spirit of the rules? nope.
Make gramma proud.

There’s a lot of gray there, but remaining open is something like, say, using minimal sized markers for the boundary/no-touch points, and a large traffic cone for the touch points. I think it’s very hard to attribute intent in this rule for things like “do all markers need to be identical,” “what are the maximum dimensions for a marker,” and the dimension question I put above. @wgorgen also had a different interpretation of these rules than I did, so clearly there’s something to be resolved there as well. I think there’s some clear “this is an exploit and against the spirit of the rules” in say, using a 4x8 plywood sheet as a marker, but at what point does using a larger marker become “against the spirit of the rules?” I can’t draw an effective line there other than a gut check, and I’m sure if you polled a dozen CDenizens you’d probably get a dozen (or more) answers there.


We’re using these:

If you take 2" velcro, cut a square, then cut that into 2 triangles, and stick them on the corners, the cones stick nicely to the field carpet. The cones are largely undamaged when a robot drives over them.

Here’s the field set up for the slalom challenge and the accuracy challenge.


We’re just using pop bottles

To incentive’s the students not running them over. We keep track of who hit which markers the most. That’s the pop they get to open during lunch.

The different colors are nice to highlight the different marker types.

We are using Gatorade bottles at the moment.

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