About Model Grids
When you are in Part or Assembly mode, you can define and use three-dimensional model grids.
You can define a model grid using the Model Grids dialog box to select a coordinate system that defines the origin of the grid. To open the Model Grids dialog box, click Annotate > Combination States > Model Grid.
For more information about creating, using, and modifying model grids, refer to the topics on model grids in the Detailed Drawings portion of the online Help system.