In the 2021 Skills Challenge, teams are given the option of shooting power cells at a 2D representation of the goal. Balls are considered ‘scored’ into this 2D region if “at least 50% of the POWER CELL is inside the boundary.”
We interpret this to mean:
Balls are considered scored if, at the moment of contact with the goal, at least 50% of the ball’s cross-sectional area is contained within the boundary of the inner port when viewing orthogonally to the goal.
The area of the ‘lens’ created by two overlapping circles of radii r, R is given by
Next, we set the lens area to be equal to half the area of the circle with radius r. Plugging in the known values and solving for d, we find d = 6.175 in.
The 2D representation of the inner port therefore has an effective diameter of 2(d+r) = 19.35 in.
But for completeness, you’d need to test how far off balls can be on the 3D goal and still ricochet in. It won’t be as much, but I think it will be a little larger than 13"
There’s far too many other unfortunate inequities in 2021 to get worked up about this. Only ~1/3 or less of the usual number of teams are participating, and I suspect even fewer will submit scores. The teams that we see showcasing their brand new robots and goals built in fully-open, covid-free shops are in the minority I think. So I don’t begrudge any team that is working with a sticker attached to a wall. Whatever helps us get through the pandemic while having a bit of fun works for me.
