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# lockConnection(from:to:)

Prevents the specified nodes from being disconnected due to the addition of obstacles.

```
func lockConnection(from startNode: NodeType, to endNode: NodeType)
```

## Parameters

`startNode`

A node in the graph.

`endNode`

Another node in the graph to which the node `startNode` is directly connected.

## Discussion

By default, adding obstacles with the [`addObstacles(_:)`](/documentation/GameplayKit/GKObstacleGraph/addObstacles(_:)) method disconnects pairs of nodes if the direct path between them intersects an obstacle. This behavior ensures that using the findPathBetweenNodes:toNode: method does not result in a path through the graph that crosses obstacles.

With certain nodes, such as those you add with the [`connectUsingObstacles(node:)`](/documentation/GameplayKit/GKObstacleGraph/connectUsingObstacles(node:)) method to represent the position of a game character or objective, this behavior might not be desirable. For example, if you add an obstacle that overlaps a character’s current position, the character should be able to find a path that exits the obstacle. In this case, use the [`unlockConnection(from:to:)`](/documentation/GameplayKit/GKObstacleGraph/unlockConnection(from:to:)) method to protect the connection between the character’s node and a neighboring node from being automatically destroyed. If you later rearrange nodes so that such protection is no longer necessary, use the [`unlockConnection(from:to:)`](/documentation/GameplayKit/GKObstacleGraph/unlockConnection(from:to:)) method to remove it.

---

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