Snap lines are entities in your drawings that help locate dimensions and detailing items, including notes, geometric tolerances, symbols, and surface finishes. After you place an item on a snap line, the item moves with the line. For example, if you place several dimensions on a snap line you can simultaneously reposition all the dimensions by dragging the snap line—while maintaining the alignment of the dimensions.

You can offset snap lines from either drawing view borders, datum planes, draft entities, drawing geometry, or existing snap lines.

Snap lines follow the drawing view or object they are attached to. For example, if you attach a snap line to a view border and then rotate the view by 30 degrees, the snap lines also rotate. Additionally, consider the following:

If you delete the datum planes, drawing geometry, or existing snap lines that a snap line is attached to, the snap lines still remain in the drawing. However, if you delete a draft entity, any related snap lines are also deleted. Any items attached to the deleted snap line remain. However, they are unsnapped and will not move together.

Snap lines are positioned relative to the selected view border, datum plane, draft entity, or drawing object. The default snap line length is primarily controlled by the selected object, which means that changes to the selected object will correspondingly change the snap line length as well. After the snap lines have been created you can independently change the snap line length by dragging the handles on the end of the snap line.