Positioning by Using P-lines
- Last UpdatedFeb 19, 2025
- 2 minute read
Keywords
PPLINE START END OFFSET
Description
A position relative to a p-line may be specified in any of the following ways:
-
As a specific distance along the p-line from its start (typically the POSS of a Section) or its end (typically POSE).
-
As a proportional distance along the p-line, expressed as a fraction of its length (typically the distance from POSS to POSE).
-
As one of its extremities; that is, at the p-line’s start or end.
-
As an offset, expressed as the distance between two specified p-lines.
Examples
POSITION PPLINE
BOS 500Calculated position is on the BOS p-line, 500mm from its start (by default); for setting a variable or for querying.
POS PPLIN TOS 1000
FROM ENDCalculated position is on the TOS p-line, 1000mm from its end.
POS AT PPLIN NA OF
/SCTN2 PROP .25Calculated position is on the Neutral Axis of /SCTN2, 25% along its length as measured from its start (by default).
POS AT PPLIN TOS OF
/BEAM1 ENDPosition is defined as the end of the TOS p-line of /BEAM1 (probably, but not necessarily, the POSE setting for /BEAM1).
BY PPLIN TOS OFFSET
FROM PPLIN BOSMoves the current element (Section or Joint) by the offset distance between its TOS and BOS p-lines.
BY PPLIN BOS OFFSET
FROM PPLIN TOSMoves the same distance as the preceding example, but in the opposite direction.
BY PPLIN TOS -OFFSET
FROM PPLIN BOSThe same effect as the preceding example.
Command Syntax
Note:
The following syntax describes only the p-line referencing options for defining a
position. These are in addition to the positioning/moving syntax described in Equipment and Primitives, which also apply to Structural steelwork elements.
Defining a specific position
>- <plin> -+- <uval> -------------.
| |
|- PROPortion - value -+----------------------.
| | |
| ‘- FROm -. |
| | |
‘-------------------------------+- STart* -. |
| | |
‘- ENd ----+--+->
Defining a distance as the offset between two p-lines:
>-- <plin> --+-- sign --.
| |
‘----------+-- OFFSet FROm <plin> -->
where <plin>, which identifies a specific p-line, is defined in Identifying P-lines.
Querying
Q <plin> --+-- <uval> --------------.
| |
|-- PROPortion - value --+--------------------------.
| | |
| ‘-- FROm --. |
| | |
‘-----------------------------------+-- STart* --. |
| | |
‘-- ENd -----+--+-->
Q <plin> -- OFFSet --+-- FROm -- <plin> --.
| |
‘--------------------+-->
Querying Examples
|
Q PPLIN TOS END |
Position of end of p-line. |
|
Q PPLIN BOS PROP 0.3 |
Position of point 30% of distance along BOS from start (by default) towards end. |
|
Q PPLIN NA PROP -1.5 FROM END |
Position of point which is 1.5 times length of Neutral Axis away from end of p-line in direction away from start. |
|
Q PPLIN TOS OFFS FROM PPLIN BOS |
Offset distance between TOS and BOS. |
|
Q PPLIN TOS OFFS |
Offset distance between TOS and Neutral Axis (by default). |