The Grid Tool

While the Construction and Snap Grid (set in the View > Grid Options > Grids and Background) is a global, equally distributed net covering the whole 2D window, and is used as an input and editing aid, the Grid Tool creates a custom local structural grid. The grid created by this tool is interactive, so you can edit grid elements even after placing them. Grid elements can be edited using Grid Settings.
To place a whole scheme of horizontal and vertical gridlines in one step, use the Design > Grid System command. The follow-up Grid System Settings dialog allows you to configure the system of Grid Elements and to place dimensions, beams, columns or optional library parts at the grid intersection points.