The break button is used to divide objects along a horizontal or vertical line. The command operates on boxes, polygons, and wires. If one or more of those objects was previously selected, the break command will operate on those selections. Otherwise, the user is asked to select objects to break. The user is then asked to click to divide the selected objects along the break line, which is attached to the pointer and ghost-drawn. The orientation of the break line is either horizontal or vertical, which can be toggled by pressing either the / (forward slash) or \ (backslash) keys when the break line is visible. The break command is useful when one wants to relocate or create a subcell from pieces of an existing design.
While the command is active in physical mode, the cursor will snap to horizontal or vertical edges of existing objects in the layout if the edge is on-grid, when within two pixels. When snapped, a small dotted highlight box is displayed. This makes it much easier to create abutting objects when the grid snap spacing is very fine compared with the display scaling. This feature can be disabled by setting the NoSnapToEdges variable.