The Subdivide Columns, Rows, and Layers dialog box is used to split columns, rows, and layers into two or more parts. The dialog box is shown by first selecting Grid|Subdivide Grid Cells/Elements... or clicking the Subdivide grid cells/elements button 
. Then the user clicks and drags on the grid with the mouse to select a range of elements. The elements over which the mouse moved with the mouse button pressed will be selected and shown in a gray color. When the mouse button is released, the Subdivide Rows, Columns, and Layers dialog box appears. In the dialog box, the rows columns and layers selected by the user are displayed. If desired, the user can edit the range of columns, rows and layers displayed. The user specifies how many columns, rows, and layers each selected column, row, and layer should be divided into and clicks the OK button to subdivide them. Each selected column, row, or layer will be split into the specified number of parts. The parts making up each former element will have a uniform width, and the total width of the parts will be equal to the total width of the selected columns, rows, or layers before they were subdivided.
When used with Footprint grids all the cells will be subdivided because the cell spacing is required to be uniform.
