Did anyone else imagine just a very large hoop?
I imagined a large funnel.
Show HN: A basketball hoop to maximize shots that go in [video]
61–70 of 172 posts
Re: Show HN: A basketball hoop to maximize shots that go in [video]
#62Any physics experts know what the actual optimal shape is? I imagine it would be a pretty gnarly problem to work out.
If you fix the position of the 'thrower' and just throw them at ridiculous speeds so gravity doesn't matter you'd end up with a hyperbolic backboard. So annoyingly for an 'optimal' solution you'd need to specify where people can throw from and how fast. Frankly you might as well just use a hyperbola with one foci on the hoop and the other on the middle of the court, or maybe a point slightly higher than the court its…
Don't forget about spin as well, which can significantly change the trajectory due to the Magnus effect
Re: Show HN: A basketball hoop to maximize shots that go in [video]
#63That was a pretty cool video! I loved how he used 3D Monte-Carlo and side-stepped all the complicated math. I wonder if he was using a Physics engine like Bullet or ODE to calculate the simulated trajectories. Also, a good intermediate step might've been to build the backboard in something like Unity and shoot some hoops to catch the radius error before actually machining it out.
> Physics engine like Bullet or ODE to calculate the simulated trajectories Probably not, the trajectories are simple parabolic and you can assume perfect elastic collision. Easy enough to implement, compared to interfacing with a physics engine. In fact, it sounded like he approximated the ball by a point and ignored the radius.
While interfacing a physics engine is hard, I feel like it would be hard to forget to add the radius in a physics simulation, making mistakes like this rather difficult.
So yeah, you can reinvent the wheel but using specialized tools gets the job done too, usually with less painful mistakes, but that's the price to pay for the lack of learning you get with the tool.
Re: Show HN: A basketball hoop to maximize shots that go in [video]
#64Any physics experts know what the actual optimal shape is? I imagine it would be a pretty gnarly problem to work out.
I do not think you can make definite claims about optimality without putting it in the context of some probability distribution over all possible incoming trajectories etc.
Re: Show HN: A basketball hoop to maximize shots that go in [video]
#65Earlier quoted context omitted.
Depends on the importance of a couple effects that light is immune to (at least for an optics equation) 1) gravity post impact with backboard 2) impact angle for a given (start, backboard) tuple depend on velocity and launch angle for a basketball, but are always the same for light. Also the impact angle for the basketball and light are very different
I think it's safe to ignore both of these factors at this scale. 1) The effects of gravity is bounded and negligible on the surface of the Earth. 2) (I suspect) the wideness of the launch angle and hoop size are probably directly proportional, so you could shape the back board based on a direct impact to get a point to center the hoop on. The hoop can only get so big and still be considered reasonable.
The effect of gravity on the surface of the Earth is hardly negligible!
And your intuition on the launch angle is just flat wrong. In fact, I believe it's one of the primary predictive factors in a shots success with a normal backboard!
Re: Show HN: A basketball hoop to maximize shots that go in [video]
#66Earlier quoted context omitted.
If you fix the position of the 'thrower' and just throw them at ridiculous speeds so gravity doesn't matter you'd end up with a hyperbolic backboard. So annoyingly for an 'optimal' solution you'd need to specify where people can throw from and how fast. Frankly you might as well just use a hyperbola with one foci on the hoop and the other on the middle of the court, or maybe a point slightly higher than the court its…
Don't forget about spin as well, which can significantly change the trajectory due to the Magnus effect
I would guess that if there is enough spin for the Magnus effect to be significant, it would also be significant with respect to the rebound, as the surfaces in contact are not frictionless. On the other hand, I am not sure there is much spin in most basketball shots, and, given a backboard designed without taking it into consideration, there would be no incentive to add spin.
Re: Show HN: A basketball hoop to maximize shots that go in [video]
#67Did other people also wonder what a French cleat might be? It is a molding with a 30–45 degree slope used to hang cabinets or other objects. [0] https://en.wikipedia.org/wiki/French_cleat
I put up a giant wall of these in my home and they're incredibly useful. You can build any type of contraption and throw a cleat on the back of it and boom, just put it on the big wall. Reconfigure it every month, build new things to mount up there, it truly is simple and versatile. French cleats truly are terrific.
Re: Show HN: A basketball hoop to maximize shots that go in [video]
#68Earlier quoted context omitted.
Maybe, but as he explains a normal parabola (like a satellite dish) wouldn't work, since the shots themselves are arced because of pesky gravity. I thought using a Monte Carlo analysis and finding a fixed point was actually a very clever way to solve it.
Yeah but the acceleration from gravity is constant so maybe there is just a (possibly non linear) change of coordinates that can be applied to the regular paraboloid. Also a paraboloid would work only for rays that are parallel to one another.
Another difference from optics is that the vlocity is not fixed, and that affects the extent to which gravity modifies the trajectory.
Re: Show HN: A basketball hoop to maximize shots that go in [video]
#69Really impressed with the use of Monte Carlo method. A while back I ran into some resistance trying to advocate simpler statistical methods to solve a problem domain similar to this, while the team in question repeatedly wanted to reach for a machine learning solution. I'd love to know if I was wrong here. In my mind, when an algorithmic or heuristic path to a solution is available, we should attempt it first before reaching for ML.
Re: Show HN: A basketball hoop to maximize shots that go in [video]
#70Earlier quoted context omitted.
Don't forget about spin as well, which can significantly change the trajectory due to the Magnus effect
I would guess that if there is enough spin for the Magnus effect to be significant, it would also be significant with respect to the rebound, as the surfaces in contact are not frictionless. On the other hand, I am not sure there is much spin in most basketball shots, and, given a backboard designed without taking it into consideration, there would be no incentive to add spin.
Backspin is an essential part of a reliable jump shot, and topspin is employed on finger roll layups close to the rim.