What forces the rest is not how far the cue ball is from you — it is where your body has to go. The cue lies on the aim line, so your chest ends up on that line about 71.1 cm behind the ball, and your feet have to be off the table. Near a cushion you stand at the side and lean on the rail. Out in the open cloth there is nothing to lean on, and that is the rest.
Drag the cue ball, the object ball or a blocker · click a pocket to aim at it · arrow keys nudge. The hollow oval is where your chest has to be; the dotted line is the lean from there to the cushion you would be standing at.
Bridging with the left hand, so a cushion running off on your left is worth about 20.3 cm more lean than the same cushion on your right.
Chest on the rail, cueing comfortably: how far past the cushion nose does your chest get?
No-leave zone shades where the cue ball must not finish for the ball you have set up. Freedom ignores the object ball and shades how much of the table you could shoot at from each spot.
A ball sitting where your hand goes is what turns a reachable shot into a spider.
A ball on a long rail with the pot running down that same rail looks brutal and is not: the line runs back alongside the cushion, so your chest lands on the rail and you stand at the side. Length of shot has almost nothing to do with it.
It is the cloth your body cannot occupy, so read it against the hollow oval, not against the cue ball.
If the object ball is between you and the end you are already near, the line pushes your body back into the middle of the table. That, not distance, is what leaves you with no stance — and it can happen with the two balls barely a foot apart.
Cueing along a cushion, it matters which side of you that cushion is on. For a right-hander it works when the cushion runs off to the left looking down the line, and costs about 20.3 cm of allowance when it is on the right. Square on to a cushion, the hand you cue with makes no odds. Flip the toggle and watch the red move.
Stance decides the rest. The spider comes from a ball parked within a hand's length behind the cue ball — roughly 3.8 cm to 33 cm back and within 7.6 cm of the line. Reachable and blocked, you raise the bridge; stranded and blocked, it is the spider.
The cue has to lie on the aim line, so once the bridge hand is placed your chest is fixed too: on that line, your bridge length plus about 50.8 cm further back. Your feet have to be off the table, so the only question is how far past a cushion nose that chest has to be — and you get to pick which cushion to lean over, whichever is kindest. A line running back alongside a rail is played from the side of the table. A line running back through open cloth leaves nothing to lean on, and no amount of reach helps.
Handedness is an allowance per cushion rather than a flat penalty: worth about 20.3 cm when the cushion runs off on your bridge-arm side, and the same against you when it is on your cueing arm, scaled by how squarely the line meets it. The one number worth measuring rather than guessing is your own lean — get down on a shot with your chest on the rail and see how far past the nose it sits. The last 15.2 cm of whatever you set is reported as a full stretch rather than a clean bridge.
Table geometry is WPA 9ft spec: 254 cm × 127 cm playing surface between cushion noses, 11.4 cm corner pockets, 12.7 cm side pockets, 5.7 cm balls.