How is a door typically represented in blueprints?

In blueprints, a door is typically represented as a line with an arc to indicate the swing direction of the door. This visual representation helps to convey not only the location and size of the door but also how it operates, which is crucial for understanding the flow of space in a building design.

The line denotes the actual door itself, while the arc illustrates the path that the door will take when it opens, allowing designers and builders to visualize the interaction of the door with walls and other elements in the space. This information is essential for ensuring that door placement does not interfere with functional areas and that there is adequate space for opening and closing the door.

Other representations such as a rectangle or solid line do not provide the necessary information about door operation. Dashed lines are generally used to indicate hidden elements or features, rather than something that is visible and operational like a door. Therefore, the choice of a line with an arc is vital for accurately conveying the function of a door in architectural plans.