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Show HN: Spin Lab (srijanshukla.com)

44 points by srijanshukla18 ↗ HN
Hey HN, I built Spin Lab: a browser-based interactive explainer for table-tennis spin. It visualizes topspin/backspin, spin rate, ball trajectory, bounce behavior, and why the opponent’s return reacts the way it does. I built it because spin is central to table tennis, but most explanations are either too hand-wavy or too static.

Thanks Fable, we miss you

15 comments

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srijanshukla18
Hey HN, I built Spin Lab: a browser-based interactive explainer for table-tennis spin.

It visualizes topspin/backspin, spin rate, ball trajectory, bounce behavior, and why the opponent’s return reacts the way it does.

I built it because spin is central to table tennis, but most explanations are either too hand-wavy or too static. I wanted something you can scrub, slow down, and experiment with.

lunchbucket
You might consider emailing hn@ycombinator.com and asking about the standing of your account.
threatripper
Are you using flight trajectories with simulated drag and lift from Magnus effect?
altmanaltman
I opened it on mobile, the first window shows up and the text cannot be scrolled through.

Also absolutely horrible UI and seems like you just put up whatever Fable shat out without checking or any thought. I am only saying this because you shared it for public feedback

srijanshukla18
Fair feedback. I've got zero UI skills - I just did put up whatever Fable gave out. That's true.

I put tons of time explaining spin physics to Fable - that was some effort on my part and that's it.

the UI feedback, I'll pass it Fable when its back :D

And yep it doesn't look good on mobile devices - try it on a desktop screen if you can, much better there.

threatripper
It would be great if we could use it for training with live measured data.
srijanshukla18
Yeah no idea but I've seen devices that are able to measure spin in real time.
N_Lens
What really sent me for a spin is how long I wasted on this demo.
kenaan
i feel like it would be better if it didn't have text that's clearly ai generated
swiftcoder
I know very little about table tennis, but this visualisation is excellent
syl5x
120 rev/s on backspin = professional loop :D

I feel like the topic just scratches the surface; there are many more things that are way more interesting to talk about here.

For example: air density actually matters. Professional players sometimes struggle to make shots in different parts of the world. The balls are not the same either. Comparing DHS with Nittaku, for example, they have different properties and a different bounce. In my part of the world, DHS is the preferred ball, compared to the US, where, at least where I’ve been, they prefer Nittaku balls.

Now about the content:

The Bounce: This could have shown all three balls at the same time, instead of showing them one after another. That would make the effect clearer.

The Answer: This feels a bit odd, and I think something in the calculation is wrong because the usual push always goes over the table on backspin.

Overall, I get that this is a very simple representation of what table tennis is, but it gives me “I did it in 5 minutes with AI” vibes.

StahlGuo
Wow,that sounds gread for the sport

Thanks Fable, we miss you

conor_robertson
I know nothing about table tennis, but love it visually! Awesome job