# <SG2> How are Horizontal Expansions Ruled in Over Under?

[SG2]
Once the Match begins, Robots may expand, but no horizontal dimension may exceed 36” (914.4 mm) at any point during the Match

I have some questions on how this rule is written.

it says "No horizontal dimension may exceed 36” " Is this the expansion or the robot itself (assuming the robot here)

The following images are assuming an 18" x 18" robot:

Assuming far corner here (36" from far corner):

Assuming closest corner to extension (36" from close corner):

So does this horizontal dimension include the corner? If so you get this weird extension zone?

So which one of these is the correct one (I am probably missing a few here)?

-Matthew
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How i understood the rule is that the expansion limit is a cylinder (due to the unlimited vertical expansion) of 36" diameter. If, at any point, your robot cannot fit in this 36" diameter cylinder, then you will be out of size. Assuming this, your diagram 1 would be the most correct, however that diagram is incorrect as while diagonally, it is 36", the rest of the diagram is not actually 36". (hope that makes sense)

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All are illegal as the farthest horizontal point to point is over 36".

We take a sizing tool with 36" length and check the robot…

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During inspection, I would take the sizing tool fully expanded (36") and see if there is any way to touch both ends to your robot while it is in any reasonable configuration.

This post gives a good explanation:

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Yup, the cylinder explanation is the easiest to think about (in my experience). Another thing to add is that this 36" cylinder will always have its base parallel to the ground. This is effective even while climbing, So, no matter your robot orientation, the horizontal profile of your robot relative to the field floor (almost like your shadow) has to be fitting within the 36" cylinder.

Please see the post immediately before yours. There is no 36” cylinder.

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