Building Grids

Custom building grids facilitate the modeling of girder grillage or grid structures. The intersections of a planar or spatial grid of lines provide definition points for nodes and members. You can use the building grid for placing objects when the object snap is activated with the 'Building grid' option (see the chapter Object Snaps). This can also be controlled quickly with the button in the CAD toolbar .

Four grid types are preset, which you can customize as needed and use for input.

Preset Types for Building Grids

In the 'New Building Grid' dialog box, you can create a user-defined grid.

Dialog Box "New Building Grid"

The Active check box controls whether the selected grid is displayed in the work window.

In the Base tab, you can define the basic specifications for the building grid.

Grid Line Coordinates

In this section, enter the position coordinates of the grid lines. Use spaces as separators (see the 'New Building Grid' dialog box). Make sure to enter the coordinates in a consistently ascending or descending order.

For a regular grid, specify the coordinate of the first line. Then add the number of additional grid lines and multiply the value by the distance (example: 4*5.000 means "four more lines, each at a distance of 5.000 m").

If you create a Specific grid by a rotation (cylindrical or spherical), you can define the rotation angles and distances in the adjusted input fields.

Grid Line Labels

In this section, specify the designations for the grid lines. The default entries are automatically supplemented when you add coordinates in the section above. The tooltip also provides useful hints here.

Origin

Set the zero point of the grid to an existing or new 'node'. You can also place the origin at any point by entering its coordinates or defining the point graphically using the button .

Options

In this section, you can influence the display of the building grid:

• Lock in graphic: The grid cannot be moved graphically.
• Consider on 'Show entire model': The grid is displayed in the full view.
• Grid points: The intersections of the grid lines are displayed.
• Grid lines: The grid lines are displayed.
• Labels: The labels of the grid lines are displayed when the options for 'Labels' are activated for the grid line start and grid line end.
• Dimensions: The dimensions of the grid points are displayed.
• Specific grid: The line grid can be inclined, rotated, or aligned to a reference object (see the Specific Grid tab).

Grid Line Start / Grid Line End

With a 'Line extension', you can extend the grid lines beyond the boundary intersection points of the lines. Enter the dimensions for the relevant axes.

Grids Without Line Extension (Left) and with Line Extension (Right)

The check boxes for the 'Label' control whether the labels are displayed on the grid lines and for which axes and line ends this should occur.

Specific Grid

The Specific Grid tab is displayed when you have selected the 'Specific grid' option in the 'Base' tab. You can change the grid type here, rotate the grid, or align it to another object.

Aligning Building Grid Specifically

Types

The 'Grid type' describes the basic geometric shape of the building grid. The following options are available in the list:

• Cartesian: The grid is created in the Cartesian coordinate system.
• Inclined: The orthogonally aligned grid is rotated by an inclination angle.
• Cylindrical: The grid is created by a rotation of points about the Z-axis.
• Spherical: The grid is created by a rotation of points about two axes.

Define the 'Coordinate system' to which the building grid refers. You can select a user-defined coordinate system in the list or create a new one using the button .

The 'Rotation type' specifies how the rotation of the building grid should be carried out. The following options are available in the list:

• Rotated via 3 angles: Rotation of the grid about the global axes by the angles α_X', α_Y', and α_Z'
• Directed to node: Alignment of grid axes X' and Y' to a node
• Parallel to two nodes: Alignment of the grid to the connecting line of two nodes
• Parallel to CS of line / Parallel to CS of member: Alignment of the grid to the local axes of a line or member

Rotation Parameters

This section is adapted to the 'Rotation type'. You can define the objects or rotation angles here.

Inclination Angle

This section is displayed for the 'Inclined' grid type. You can define the rotation angles α about the X, Y, and Z axes here.