With Snap to Grid, the SmartCursor snaps to set points on the snap grid. For example, if the grid is set to 1”, as the mouse moves over the grid, it automatically “catches” every inch. When creating a line, the line’s first and last point should (if no other constraints are active) lie on the grid. Snap to Grid is the only constraint that does not provide any sort of visual cues. If Snap to Grid is on, the mouse is always on the grid, unless other constraints are also selected which override Snap to Grid.