A massé is a shot where the cue ball curves instead of rolling in a straight line. You hit it off-center with the back of the cue raised, and the ball bends as it travels. Players use it to get around a ball that is blocking a straight path to the one they want to hit.

Why does the cue ball curve?

A normal shot hits the cue ball through its center, so it slides and then rolls forward in a straight line. A massé changes two things at once: where you hit the ball, and the angle of the cue.

When you raise the cue and strike off-center, you put spin on the ball around a tilted axis instead of a flat one. Part of that spin points down into the cloth. The cloth grabs it, and the friction pushes the ball sideways from its starting direction. The ball leaves roughly where you aimed, then the spin drags it into a curve. The steeper the cue and the harder the off-center hit, the tighter the curve.

Massé or swerve?

People use both words, and the line between them is soft. A swerve is the gentle version: a small cue elevation, a slight bend in the path, the kind of thing that happens almost by accident when you play with side spin and a raised cue. A massé is the deliberate, dramatic version, where the cue is steep, sometimes nearly vertical, and the ball hooks hard. It is the same effect either way, just a steeper cue and a harder off-center hit.

How RealPool simulates it

RealPool does not script the curve. There is no animation that says "bend the ball now." The curve falls out of the same strike math that handles every other shot.

When you take a shot, the engine turns your tip position and cue elevation into a spin vector for the cue ball. Raise the cue and hit off-center, and the spin axis tilts, exactly the real-world cause of a massé. From there the normal cloth friction takes over and the path curves on its own. This follows the cue-strike model from David Alciatore's technical proofs on billiard physics, which is where a lot of RealPool's numbers come from.

There is a built-in limit, too. If you push the tip offset too far from center, the engine clamps it, because past about half the ball's radius a real cue tip slides off the ball and miscues. So you can lean on spin, but you cannot cheat physics for a curve that a real player could never hit.

In RealPool the curve comes out of the strike model itself, so it is not a special case added on the side. The practice sandbox lets you set up a blocker and try to hook around it yourself.

Common questions

Can you massé in any direction?

The ball curves toward the side you put spin on. Hit the right side with the cue raised and it bends right, hit the left side and it bends left. How far it bends depends on how steep the cue is and how hard you hit.

Is a massé legal?

Yes, the shot itself is legal in standard rules. What gets people in trouble is the contact: with the cue steep over the ball it is easy to double-hit or miscue, and those are fouls. A clean massé that obeys the normal contact rules is fine.