A grid system is a set of intersecting lines used to aid in drawing the model. Grid systems may be Cartesian (rectangular), cylindrical, or general. Each grid system is defined with respect to the Global coordinate system. An unlimited number of grid systems can be defined, each with a unique name.
Grid System Type options. Choose to define a Cartesian or Cylindrical system.
A Cartesian (rectangular) system has grid lines parallel to the X and Y axes of the grid coordinate system.
A cylindrical system has radial and circumferential grid lines. The radial and circumferential grid lines are parallel to the X-Y plane of the grid system.
X/R Grid Labeling and Y/T Grid Labeling options. Use these options to specify the grid labeling scheme. Use the First Grid Label edit boxes to specify the beginning alpha or numeric character upon which subsequent labels will be based. Use the Labeling Direction drop-down lists to specify that the labeling move form left to right or right to left and bottom to top or top to bottom.
Grid System Origin and Orientation (Plan) options. Use these options to specify the offset of the new gird system from the Global coordinate system.
Global X edit box. Use this edit box to specify the offset, in current length units, of the X coordinate of the origin of the new gird system from the origin of the Global coordinate system.
Global Y edit box. Use this edit box to specify the offset, in current length units, of the Y coordinate of the origin of the new grid system from the origin of the Global coordinate system.
Rotation about Global Z (deg): The angle, input in degrees, specifies the orientation of the positive X-axis (or theta equals 0 degrees radial line in a cylindrical system) of the grid system relative to the positive global X-axis. The angle is measured from the positive global X-axis to the grid system X-axis. Positive angles appear counterclockwise when viewed from above. The figure below shows some examples. The figure shows the global X-axis and the orientation of the X-axis for the added system. Figure "a" shows an example where the rotation angle is specified as 30 degrees. Figure "b" shows an example where the rotation angle could be specified as either 330 degrees or -30 degrees.
Grid Dimensions (Plan) options. Use these options to specify the number and spacing of the grid lines in the X/R and Y/T directions.
Access the Add New Grid System Quick form as follows:
Click the Edit menu > Edit Stories and Grid Systems command to access the Edit Story and Grid System Data form.
Click the Add New Grid System button.