The Grids task creates and manipulates coordinate systems, elevation planes, vertical grid planes, radial cylinders/planes, grid arcs, and grid lines. Coordinate systems provide a locating scheme when working in the model. The grid lines of a coordinate system represent the relative positioning requirements for a specific design purpose. When designing your model, you may want different coordinate systems for individual pipe racks, buildings, or areas of the model.
When designing your ship, you may want to create a main coordinate system with grid and Z planes every meter. The grid planes and Z planes of this coordinate system would be used to place the major plate systems of the ship such as the decks and bulkheads. You may also want to create separate coordinates systems for individual cargo spaces and machinery spaces to help with the placement of equipment.