Billiards

Two equal spheres, a cloth and a rubber rail — and every one of the shelf's mechanics equations turned into a shot. Momentum and energy give the tangent line; friction between the balls gives throw; the tip's offset gives spin; the cloth turns that spin into follow, draw and stun. The lab below runs those equations live — set the shot up yourself: drag both balls, pick a pocket, and watch what speed does. It is the same physics, and the same numbers, that the Pool Sauce engine integrates.

The shot lab

show

Drag the cue ball or the object ball anywhere on the cloth; click one of the six 4½″ pockets to aim at it. The cue is always aimed at the ghost ball — and when the cue ball is on the wrong side for a direct pot, the lab aims a one-rail bank instead, with the cushion's real rebound (not a mirror) solved into the contact point. Whether the shot actually drops is then up to speed, spin and throw.

No guides, neutral defaults. The aim must pay for throw, squirt and swerve.
Drag either ball; click a pocket to aim there. The outcome maps live under the table.
Drag the empty cloth to point the cue; drag a ball to move it.
← → a degree a press, shift for a tenth. In practice this walks the aim off the ghost-ball line, so you can see what a degree of error costs; in pro it is the whole aim.
Also the cue ball's speed in m/s: 2–3 pot weight, 5 firm, 8+ a break.
Poke the ball. The sliders below follow, and so does the shot. Outside the inner ring the tip slides off the ball — that is a miscue, and the ring is where it starts.
+0.4 natural roll · 0 stun · −0.5 draw · ±0.5 is the miscue limit.
Negative is left of centre. Side squirts the cue ball off the aim, swerves it back while it slides, and throws the object ball.
shots to try
balls on the table
Every ball is live — combos, caroms, full breaks. Practice aims at the lowest number still up (ringed).
conditions — the contract
Practice grades live, pro on execute. Conditions that fight each other make the best shots.
cue ball, before cue ball, after — sliding then rolling object ball tangent line · line of centres · aim line object ball with no throw

Object ball

Cue ball

Outcome by strike this shot, every strength

dropshangsrattles outstays upnever gets therecue ball scratches (lower strip)

Solution space aim × strike, this layout

potshangsrattles outscratches
Every pixel is a simulated shot. Across: aim either side of the ghost-ball line (the dark tick), zoomed to the window where the ball drops — often a tenth of a degree — or ±5° with the toggle. Up: strike 0.5→10 (the line is yours; the amber tick is your trim). A red lower edge means it pots but scratches. The window sitting off the ghost line is the compensation you must aim.

Contact & throw

No rails, no pockets, no rack: two balls and the moment they touch. Where you strike the object ball decides where it goes and where the cue ball goes — and side spin bends the first of those, which is the part that costs frames. Drag the contact point around the object ball, add side, and watch both paths answer. Everything here is the same collision the shot lab runs; it is just the only thing on the table.

Drag either ball anywhere, and drag the amber handle round the object ball to choose where you strike it. The cut angle and the ball-hit fraction follow from that; the distance follows from the balls.
Side does three things here: it squirts the cue ball off the aim at the tip, swerves it back while it slides, and rubs the object ball at contact — that last one is throw, and it is the one that moves the object ball off the line you aimed.

How far throw carries

Throw is not a fixed number of degrees. It rises as the surfaces rub harder and falls as they slip faster, so a soft shot throws more than a firm one and the object ball drifts further the longer it has to travel. The curves are this shot at every strike on the scale; the amber mark is where you are.

Kicks and banks — the diamond systems

The diamonds are a calculator bolted to the rails. Two systems that use it are drawn here — the two-rail mirror, which is pure geometry, and corner five, the three-rail system every carom player learns — and both are run against the same cushion model as the rest of the page. That is the point: the mirror is exact only for a ball that loses nothing at the rail, and corner five is an empirical system, calibrated for running side at one particular pace. Drag the balls, then move the speed and the side and watch the arithmetic drift out from under you.

Top is what the systems assume: the ball arrives at the first rail already rolling. Stun or draw reaches the rubber still sliding, and the cloth bends it after every cushion until it rolls again.
Corner five is taught with running side at a firm, even pace — that english is part of the system, not a decoration. Zero it and watch the numbers stop working.

The cushion

Running side has the ball's surface moving against its travel at the rail, so friction speeds it along; reverse does the opposite.

Slide → roll

Off the tip a struck ball slides: the cloth is dragging one way and the ball is spinning another. Friction eats the difference until the surface speed matches the ball speed — natural roll — and from then on the ball has forgotten what you did to it. Everything you meant by draw, stun or follow lives in the stretch before that. Set the three things that decide it and watch where the crossing falls.

How far it travels before you care — usually the gap to the object ball.

Drills & minigames

Two ways to make the table ask something of you. A drill lays the balls out for its level and moves you up on a pot, down on a miss — ten levels, each a little harder. The run-out is a game: every executed shot advances the table, so the cue ball you park is the cue ball you play next. Both drive the table in the shot lab, and starting one takes you there.

Every executed shot advances the table — the balls live where they land. Lowest ball first or it's a foul (ball in hand; a fouled 9 respots); the run ends when the 9 drops, or the cloth is bare. Par is a ball a shot. Import a break from a photo and clear it.
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The table sets itself up; 10 levels each. In pro a pot moves you up, a miss down — the format of Dr Dave's drills & exam library.

The conditions — clean hit, no rail, kick first, three rails, called pocket, pocket speed, carom, nothing else moves, safety — stay on the shot lab itself, because they grade the shot you are aiming right now and you want to watch them while you drag.

Layout library

Positions worth knowing, and a shelf for your own. Each one loads onto the shot lab exactly as stored — the balls, the pocket, the strike, the tip and the side — so a layout is a shot you can hand to someone else. Save what you are looking at, and it stays in this browser; copy its link and it travels.

Your shelf

The numbers

The lab runs on these — quoted from poolsauce/constants.py in the pool-sauce-engine repository, so the page and the engine never disagree on one. Where the engine has no value yet (ball–ball friction, cushion friction) the literature's is used and marked.

The equations

What the lab leaves out

The skills

Physics from the Equations shelf; constants from pool-sauce-engine. Coriolis, Théorie mathématique des effets du jeu de billard, 1835, had most of this; the throw model follows Alciatore (The Illustrated Principles of Pool and Billiards, technical proofs). Nothing here is a substitute for a table.