2D obstacle used in navigation for collision avoidance. 2D obstacle used in navigation for collision avoidance. The obstacle needs navigation data to work correctly. This can be done by having the obstacle as a child of a [Navigation2D] node, or using [method set_navigation]. [NavigationObstacle2D] is physics safe. Returns the [Navigation2D] node that the obstacle is using for its navigation system. Sets the [Navigation2D] node used by the obstacle. Useful when you don't want to make the obstacle a child of a [Navigation2D] node. Enables radius estimation algorithm which uses parent's collision shapes to determine the obstacle radius. The radius of the agent. Used only if [member estimate_radius] is set to [code]false[/code].