ISODRAFT
User Guide
Design Requirements
:
Reference Dimensions
: Setting up a Reference Datum
Setting up a Reference Datum
For an element to be used as a reference datum, it must have:
•
An origin.
•
An SKEY attribute, or a parent with an SKEY attribute.
The elements the user can set up as reference datums are:
•
Datums;
•
Equipment;
•
Equipment and structural primitives such as boxes;
•
Sections;
•
Piping components;
•
Point elements, if they have a parent with an SKEY attribute.
SKEY Attributes
Elements used to define reference datums must have an SKEY attribute, or a parent with an SKEY attribute (but note that the parent element need not be the immediate owner of the element). If the element does not have an SKEY, and no parent has an SKEY, miscellaneous SKEY types (see below) will be used.
Elements with SKEY attributes are:
Datums
Equipment
Pipes
Structures
Substructures
Drawings
Frameworks
Subframeworks
Different SKEY types have different ATEXTs associated with them, as shown in the following table.
SKEY Type
Item Type
ATEXT
Default text
HST*
Horizontal steelwork
element
460
BEAM $?
VST*
Vertical steelwork element
461
COLUMN $?
BLD*
Building
462
? $BUILDING CL
EQU*
Equipment item
463
CL EQUIPMENT $?
PIP*
Piping component
464
CL PIPELINE $?
FLR*
Floor level
465
? $FLOOR LEVEL
WAL*
Wall
466
? $WALL
GRD*
Grid line
467
GRID LINE $?
XXX*
Miscellaneous
468
?
In SKEY Types above, the symbol * represents any character. In Default texts, $ is replaced by a new line and ? is replaced by the name of the element. If the element does not have a name, ISODRAFT looks up the hierarchy until it finds a parent with a name, and then uses that parent’s name.
If the reference element is a Datum element, it will have an STEXT attribute. The user can set this attribute to any identification text required. If the user does this, the text they enter is used instead of the name. If the user leaves STEXT unset, the Datum name is used.
Set the SKEY text to the SKEY type required. Note that the user can also redefine the text in the ATEXT element using the ATEXT command.
For example:
Pipe PIPE7-1 has an SKEY type VSTC. Associated with the pipe is ATEXT 464, with default text CL PIPELINE $?. The following text will appear on the isometric (see
Figure 5:1.: Example plot file
):
CL PIPELINE
PIPE7-1
Figure 5:1.: Example plot file
also shows a reference to a Datum, which has its STEXT element set to Zero Elevation.
Figure 5:1.
Example plot file
Origins and Centrelines
On the isometric, a centreline is drawn through the origin of the reference element. The reference dimension will be drawn from the centreline of the reference element.
The centreline will normally be the Z-direction of the element, as defined by its orientation.
•
For Piping components the p-leave will be used.
•
For Sections the p-line direction will be used.
•
For Points, the direction of the centreline will be to the next Point in the list. For the last Point in the list, the direction from the previous Point will be used. If there are no other Points, the direction will be the Z-direction of the Point’s owner.
1974 to current year.
AVEVA Solutions Limited and its subsidiaries. All rights reserved.