This sketchup extension is useful to create 2D or 3D grids with X step, Y step and Z step parametric, at any orientation on any plane. Each 2D and 3D is a named group. Once you have installed this plugin, Make the tool visible by checking the 3D Grid tickbox in View/Toolbars and you are ready to draw lines that snap to the intersection points on this grid. It will certainly makes your drafting lot more easier. Grid set up is really easy like 1X1 meter and draw out the grid to the size needed, and then you can quickly draft in walls.