VEX Horizontal Expansion with Other Materials

Say for example, would a team be able to use a set of stings to horizontally expand during the endgame?

Hi Toby, welcome to the vex forums! Please utilize the search bar to see if other topics like yours already exist before posting.


Also remember to read the game manual for any questions about legality. For your question specifically you can check out rule <R7> part e.

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Yes, I am aware of that. So you would say this would be a valid way of playing the endgame?

Do the rules say if it is illegal?


The short answer is submit a question. But in the past, there has been a requirement that expansion parts have a rigid backing.

Ok, thanks for your help.

there has been no such requirement in any game as far as I can remember. Many robots have used compliant or otherwise non-rigidly backed expansions with no issues in the past.

The thing to take note of for the endgame expansion this year is how far you are willing to push the entanglement hazard of your robot. Ultimately, the decision of whether or not a mechanism poses a risk of entanglement is something left up to the referee, which means that if you are really pushing it with something like a string launcher, you are running the risk that a referee will determine your robot to pose a risk of entanglement. But no, using string to expand is not inherently illegal, and has been done in the past for things like wallbot tethers.


Xenon27 I do believe I’m right about rigid backing being required in the past. I’m not on here as much as you but I have been around a bit longer and am known for having a good memory. My recollection was based upon those instances in the past where teams competed with tetherbots. A quick search of tetherbot here on the forum brought up this from a Starstruck Q&A circa 2016-2017

And while I have yet to find chapter and verse he is referring to, I think Karthik is a good enough authority that rigid backing was previously required. But as always, the official answer needs an official Q&A.

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I can’t speak for the distant past, but in recent history (at least turning point and upwards, but I honestly don’t imagine that this was ever a rule in the manual) the manual has never stated that robot expansions need to be rigidly backed, and no q&a since that one from 5 seasons ago has indicated this to be the case. And this q&a states that string based expansion mechanisms would indeed be legal, so long as they do not violate other rules.


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