# Grid planes
A grid plane defines the geometry of a surface, and the load behaviour of the grid plane is defined by a grid surface.
The grid plane data table is available in the Data explorer. The Grid plane definition dialog can be activated from the grid planes table view by giving the Edit > Wizard menu command. Wizard is also available on the Data options toolbar and on the right-click menu for the table view.
Refer to Use of grid planes and grid surfaces for a general description of grid planes and their use.
# Grid plane
# Name
The name is used only as a label for the grid plane. Where grid planes have to be selected this is the name that will be displayed.
# Type
The grid plane can be either a general grid plane or a storey grid plane. A storey grid plane must exist in a global XY plane.
# Grid axis
Grid planes reference an axis set. This may be global or any user defined axis system. The grid plane is parallel to the xy plane of this axis set.
# Grid elevation
For situations where grid planes are to be stacked at different levels the grid elevation allows the grid plane to be offset from the axis origin in the local z direction. The elevation defines the height of the grid plane above the origin.
# Grid plane tolerance
The grid plane tolerance is used to determine whether an element lies in the grid plane.
# Storey tolerance below/above
Nodes are associated with the storey if they lie within these tolerances of the elevation. The different tolerance above and below are to allow for situations where there may be a step in the floor levels but these are to be considered as a single storey at the specified elevation. If the tolerance is set to auto then the nodes are associated with the nearest storey.