Grid systems are defined by specifying their origins and orientations with respect to the fixed Global Coordinate System, which is the only coordinate system used in the program. Identified as "Global," it cannot be deleted so it always exists, and its Global origin is always X = 0, Y = 0, and Z = 0.
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. An unlimited number of grid systems can be defined, each with a unique name.
Cartesian (rectangular) or cylindrical grid systems are the primary grid layout options. A cylindrical system is based on a set of radial and circumferential grid lines. General grids, which are arbitrarily defined grid lines, may be added into a rectangular grid system.
Note: To define a cylindrical system use the Edit menu > Edit Stories and Grid Systems command (or Edit Towers, Stories and Grid Systems command) > Add New System button, and choose the Cylindrical option on the Add New Grid System Quick form.
The Grid System Data form has the following options.
Grid System Name edit box. Use the default or enter a new name for the grid system.
System Origin options. Use these options to specify the offset of the grid system from the Global coordinate system, if any.
Global X edit box. Use this edit box to specify the offset of the X coordinate of the origin of the new grid system from the origin of the Global coordinate system.
Global Y edit box. Use this edit box to specify the offset of the Y coordinate of the origin of the new grid system from the origin of the Global coordinate system.
Rotation (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 grid 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.
Note: When the Grid System Data form is displayed by clicking the Edit Grid Data button on the New Model Quick Templates form, the System Origin options are disabled. This means that the grid system for models started from templates will be aligned with the Global Coordinate System.
Story Range options - Use these options to specify a range of stories for the grid system being defined. That is, the grid data specified on the Grid System Data form will apply to the specified story range: the Default-All Stories option or a User Specified Top and Bottom story as selected in the drop-down lists.
Note: When the Grid System Data form is displayed by clicking the Edit Grid Data button on the New Model Quick Templates form, the Story Range options are disabled.
Click to Modify/Show buttons
Reference Points button. Click this button to access the Reference Points form. Use the form to specify the location of a reference point that is then projected as a vertical line.
Reference Planes button. Click this button to access the Reference Planes form. Use the form to establish the elevation (Z ordinate) of a horizontal reference plane. The main purpose of those planes is to provide a horizontal plane/line that can be used to snap to when drawing objects in elevation views.
Options
Bubble Size edit box. Specify the size of the bubble to be used to delineate the grid line ID.
Grid Color box. The color that will be used to display the grid lines is shown here. As necessary, click this box to display the Color form and select a new color to be used to display the grid system.
Diagram -- As changes are made on the form, this diagram will update to illustrate those changes.
Quick Start New { Rectangular, Cylindrical} Grids button. Clicking this button displays the Quick {Cartesian, Cylindrical} Grids form. Grids defined using the Quick {Cartesian, Cylindrical} Grids form will replace the grid data shown in the {Rectangular, Cylindrical} Grids speadsheet area; General grids will not be affected.
Display Grid Data as Ordinates or Display Grid Data as Spacing options. Choose to display the locations of the points defining the grid line using coordinates or lengths relative to the origin. The ordinates or the spacing will display in the {X, R} Grid Data, and {Y, T} Grid Data spreadsheets.
{X,R} Grid Data spreadsheet area. Use the Grid ID, X/R Ordinate, Visible, and Bubble Loc (location) cells to specify the labeling scheme, coordinates, visibility, and bubble location for the grid label ID in the X/R axis direction.
{Y,T} Grid Data spreadsheet area. Use the Grid ID, Y/T Ordinate, Visible, and Bubble Loc (location) cells to specify the labeling scheme, coordinates, visibility, and bubble location for the grid label ID in the Y/T axis direction.
Click the Add button if additional grid lines need to be defined.
Click the Delete button to remove a grid line.
Click the Sort button to arrange the data in sequential order.
General Grids spreadsheet - Use the spreadsheet to specify the Grid ID, the X1, Y1, X2, Y2 coordinates, visibility, and the Bubble location for the grid lines of a general grid system. The grid lines can be specified to be visible or invisible.
Click the Add button to begin entering the data necessary to complete the definition.
Click the Delete button to remove a general grid line.
Note: When the Grid System Data form is displayed by clicking the Edit Grid Data button on the New Model Quick Templates form, the General Grids spreadsheet is not included on the form.
Access the Grid System Data form as follows:
Method 1:
Click the File menu > New Model command to display the New Model Quick Templates form.
Select the Custom Grid Spacing option
Click the Edit Grid Data button.
Method 2
Click the Edit menu > Edit Stories and Grid Systems command to access the Edit Story and Grid System Data form.
Note: If the Options menu > Allow Multiple Towers command has been enabled, the Edit menu > Towers, Stories and Grid Systems command will be available and used in place of the Edit Stories and Grid Systems command to access the Tower, Story and Grid System Data form.
Highlight a Grid System definition in the Grid Systems display area.
Click the Modify/Show Grid System button.