Stepping out of a crowd: a player who starts boxed in finds a way clear of everyone

basketball.casa is a basketball league where every game is simulated. Nobody scripts the plays. Each one comes out of who the players are at that moment: how tall, fast and tired they are, what they can see, and what they decide. You can watch any game back exactly as it happened. This update is small and about crowds: what a player does when the move they want starts with someone already in their way.

The nearest way out that is really out

Sometimes a player sets off pressed against another body, a ball handler leaning on their defender, say. The game has always walked them round that one body first. But on a crowded floor, the shortest way round the first body could run straight into a second player standing beside it. Now the step-out turns, a little at a time to either side, until it finds the nearest way round that is clear of everyone. When a teammate is standing right next to the defender, it takes a wider circle round the pair.

We checked it on thousands of crowded starting positions built to be awkward. Before the change, about one in four of them sent the player through a neighbour. Now none do.

Only where it is needed

The wider circle is only for that first step out. We tried giving every drive to the basket the same wide berth, and it made drives worse: a driver swinging wide round a pair of players left the defender they had just beaten close enough to touch. So a drive still cuts as tight as it can, and only a player starting boxed in takes the long way round.

Why it matters

Every move in the game is a body getting from where it is to where it wants to be, around the other nine. Getting that right one situation at a time is what lets the replay show a play the way the bodies would really make it. In a replay, watch a guard set off from tight against their defender: the first step now goes round the crowd, not through it.