Grids can be configured for the OpenPlant Isometrics Manager via the Gridlines.txt file which is located in a style's Config directory such as shown below:
...\WorkSpace\Projects\OPModeler_Imperial\DataSet\Isometrics\Styles\As-Built\Config\Gridlines.txt
When working with AutoPLANT Modeler, the Gridlines.txt file is located in the following location:
...\Bentley Plant V8i Projects\%PROJECT%\Config\OpenPlant\Isometrics\Styles\%As-Built%\Config\Gridlines.txt
What are Grids?
A grid is a collection of grid lines. Each of the grid lines maintain the following properties:
Is named
Is bounded (It has a start point and an end point)
Is parallel or perpendicular to other grid lines in the grid.
Is on the same elevation as other gridlines in the grid.
Grids are normally associated with a building (either structure or area) and usually define a local coordinate system for that building.
The North direction and plant coordinates are expressed relative to the local coordinate system. A grid is not necessarily Cartesian, and the grid lines are perpendicular but not always equidistant.
Another use for a grid is for relative dimensioning / referencing. When used for erection purposes, it is easier to interpret a relative offset to a column (grid intersection) than to interpret a global offset. A column reference would look similar to the image below:
How to Specify a Grid
A grid is defined by specifying values for the following statements taken from the Gridlines.txt file which is located in the style Config directory as shown at the top of the page:
GRID <name>
GRID starts the definition of a new grid (keyword)
<name> the name of the grid
Example: GRID floor_A
ACS <origin> <angle>
ACS specifies the local coordinate system for a grid (keyword)
• <origin> specifies the origin of the ACS
• <angle> specifies the counter-clockwise angle of the north direction relative to the global
North
Example: ACS 0 0 0 20
LINE <name> <dir> <start point> <length>
LINE specifies a single grid line in the grid (keyword)
• <name> the name of the grid line
• <dir> the nominal direction of the grid line, either N or E
• <start point> start point of the grid line
• <length> the length of the grid line
Example: LINE A N 0 0 0 20000
LINESET <name> <dir> <start point> <length> <cnt> <offset>
LINESET specifies a set of equidistant grid lines in the grid (keyword)
• <name> the name of the grid line. Note that for a LINESET the first letter is used to detect
if it is a digit. If so line names start from 1 otherwise line names start from A
• <cnt> the number of grid lines wanted
• <offset> the distance between the grid lines. When lines are running in North the offset value
is in East direction, when lines are running in East the offset value is in North direction
Example LINESET A N 0 0 0 20000 11 2000
Multiple LINESET and LINE statements can be used to define a single grid.
Example #1
A sample grid named ”Floor_A” is shown below. It consists of 3 gridlines in North/South direction named A, B, C and 6 lines in East/West named 1 to 6. The local coordinate system can be located anywhere in- or outside the grid, here it is located in the left lower corner of the grid. The North/south grid lines are 10000 apart, the East/West lines are 2000 apart. The red dot is a location point and mentioned are the coordinates in
the global plant coordinates system (WCS) , the local grid coordinate system (ACS) an a column reference dimension.
The specification lines are given in the picture. The text specification for this grid would be as follows:
GRID Floor_A
# the local coordinate system is offset (20000, 10000, 0) for the global origin and has zero rotation
ACS 20000 10000 0 0
# Lines running North/South. The first line starts in (0,0,0) relative to the ACS and run 10000 units in
NORTH direction
# the other 2 lines are offset 10000 from this line in East direction
LINESET A N 0 0 0 10000 3 10000
# Lines running East/West. The first line starts in (0,0,0) relative to the ACS and run 20000 units in
EAST direction
# the other 5 lines are offset 2000 from this line in North direction
LINESET 1 E 0 0 0 20000 6 2000
Example # 2
The grid definition is basically the same as in example #1 but rotated 5 degrees counter-clockwise.
The text definition is the same as in Example 1 except for the ACS line. (Note the last column has a value of 5 which represents a 5 degree counter-clockwise rotation.)
ACS 20000 10000 0 5
How Grids are used by the OpenPlant Isometrics Manager
Currently the grid implementation is done using the Isoextractor Tool. When an isometric DGN is to be created a pseudo COG is calculated by adding up the coordinates of all ports and dividing that by the number of ports. The grid that contains this point will then become the active grid and its local coordinate system is used to rotate the isometric to the grid. When multiple grids are defined at the same location but with different elevations (platforms) the grid is chosen where the COG has the smallest positive Z- distance to the grid. Depending on the configuration, the coordinate labels can be output either relative to the grid coordinate system, relative to a column intersection, or both.
For a grid line intersection to be valid, the point in question should be able to project physically on both a NORTH and EAST gridline. Physically means the projected point is between the start and end points of the gridline. If column based dimensioning is configured and no valid intersection can be found, then the local grid coordinate system is used.
Configuring Isometric Manager to use Grids
For Grids to be used in the OpenPlant Isometric Manager, the following configuration variables need to be defined:
IE_GRID
This variable specifies the location of the grid definition file. It is to be added to isoproj.cfg (located in the Workspace\Projects directory) and does not need to be explicitly defined or valid.
IE_GRID = $(IE_CONF)gridlines.txt
When working with AutoPLANT Modeler, the isoproj.cfg file is located in the ...\Bentley Plant V8i Projects\%PROJECT%\Config\OpenPlant\Isometrics\ directory
Style Configuration Variables
The remaining variables used to configure the use of Grids are defined on a per style basis in the style.cfg file. This file is located in the style's Config directory.
IE_TextGridLineSeparator
This variable specifies the separator between the grid line names in column referencing. Any ’@’ in the definition is replaced by a space. The default value is "-".
IE_TextGridLineSeparator = -
IE_TextGrid
This variable specifies the referencing part of a reference dimension. Any '@’ in the definition is replaced by a space. The default position of the text is before the coordinate. The position can be set at the end by starting the definition with a %.
If the variable is defined as shown below:
IE_Textgrid = From Col:
The reference dimension displays as follows:
If a % precedes the value as shown below.
IE_Textgrid = %From Col
IE_COORD_OUTPUT
This variable specifies how coordinate labels are displayed.
#-----------------------------------------------------------------------------
# IE_COORD_OUTPUT =
# 0 output no coordinate labels
# 1 output coordinate label in plant coordinates
# 2 output coordinate label in column line references
# 3 output coordinate label in both ways, each in a separate label
IE_CoordOutput = 1
Note that option 0,2 and 3 are new options.
IE_COORD_SWAP
This variable specifies the order in which North/East appear in the labels.
# IE_COORD_SWAP =
#
# 0 output coordinates in E/N/EL order
# 1 output coordinates in N/E/EL order
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