You sketch, place, and name global reference datum planes, axes, coordinate systems, and points in a notebook to convey the assembly design intent. Although the datum geometry in notebooks has only visual significance, you can declare the datum names in a notebook to corresponding datums in associated parts to prepare them for automatic assembly.

For example, when two parts reference the same global datum axis, the system will align those axes. When two parts reference the same global datum plane, those surfaces are aligned. Establishing these references facilitates automatic assembly and preserves design intent when you modify part details.

Because notebooks are two-dimensional, the datum planes are displayed on edge with surfaces normal to the notebook sheet. The coordinate systems always have their xy-plane on the plane of the notebook sheet.