Описание тега skphysicsbody
An SKPhysicsBody object is used to add physics simulation to a node. When a scene processes a new frame, it performs physics calculations on physics bodies attached to nodes in the scene. These calculations include gravity, friction, and collisions with other bodies. You can also apply your own forces and impulses to a body. After the scene completes these calculations, it updates the positions and orientations of the node objects.
An SKPhysicsBody object is used to add physics simulation to a node. When a scene processes a new frame, it performs physics calculations on physics bodies attached to nodes in the scene. These calculations include gravity, friction, and collisions with other bodies. You can also apply your own forces and impulses to a body. After the scene completes these calculations, it updates the positions and orientations of the node objects.
To add physics to a node, create and configure an SKPhysicsBody object and then assign it to the physicsBody property of the SKNode object. A physics body must be associated with a node object before you apply forces or impulses to it.
Click Here for Apple's Documentation of SKPhysicsBody.