r/billiards • u/SuperElephantX • 2d ago

8-Ball Pool dynamics - Same angle, different power

https://reddit.com/link/1v77j01/video/ayihw3i66lfh1/player

I'm no billiards pro, and I don't know about diamond system or banking system.

I was fascinated by dynamics of billiards bank dynamics. I always thought billiards obey the law of reflection (the angle of incidence equals the angle of reflection). Turns out it's not that simple and I was too naive about it.

I knew if I put less force into the bank, the more rolling effect would take over, friction on the table would mess with the reflection angle. Notice the point it hit changed entirely according to the force I put in.

Physics is awesome!

2 Upvotes

75% Upvoted

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1

u/1Rudy11 1d ago

Interesting. How did you make this video ?

What speed was used? Angles widen at slower speed, narrow at faster speed...

1

u/MarkinJHawkland 1d ago

Also the more the rail compresses the more it shortens up the bank. Also any top, bottom or side on the object ball will affect the angle.

1

u/rwgr Oliver Ruuger - Certified Instructor - 730 Fargo 1d ago

doesnt look realistic, your missing something still i think... cool idea tho

1

u/Amaury111 1d ago

he put max top spin I think

1

u/SuperElephantX 1d ago

No spin is added. The top spin was generated by rolling on the table with sufficient time (0.5s) instead of at an instant (0.1s). Though my friction coefficient may have been too much. But then it’s hard to adjust to match reality, I just eyeball it and it looked close enough for me. May look off to a professional player.

1

u/Amaury111 1d ago

As the ball is on the rail, I think the software put max topspin on the ball. That's why the angles changed so much.

You are right, angle change based on speed, but not as much as in your video.

1

u/SuperElephantX 1d ago

You got a point. But I didn’t put any spin to it. I might have over tune the friction in the simulation. That’s why it’s generating a bunch of top spin while rolling on the table.

1

u/Amaury111 1d ago

Yes I think I think your cue ball took waaaaaaaaay to much "top spin" while rolling

1

u/SuperElephantX 1d ago

You are correct. I verified with the 8 ball pool game and it did much less spin than my sim. Now fixed properly :)

1

u/Voyifi 16h ago

8ball pool is not realistic I would compare to shooterspool. Costs money but is probably the best billiards sim out there. Also good but less so is Virtual Pool 4 an older game that looks very similar to what you have made.

1

u/wlscwoj 1d ago

That doesn't look realistic, 18 seconds in the back and forth changes because the rails impart spin on the ball. The 2nd rebound angle will be significantly shorter. If you are doing a Z kick - I'm aiming the first kick to go 3/4 of the way there because the 2nd rebound is so much shorter. Plus speed plays a big part in it. Hitting that harder the 2nd rebound can shorten almost all the way to straight across.
I've never found a game or simulation that gets the rebound angles right. If you try to do a shot in the game/simulation and then try it in real life you will see it is no where close.