Reversing Section Start and End Positions (‘Flipping’)

Model Reference Manual

Structural Design Using Catalogue Components : Repositioning Steelwork Elements : Reversing Section Start and End Positions (‘Flipping’)

Keywords:

FLIP

Description:

The FLIP command mutually exchanges references to the Start and End of a steelwork Section, effectively reversing its orientation. This is mainly of use for reorientating a Section with a non-symmetrical profile if the user has mistakenly strung it the wrong way round. It is best used before any Secondary Nodes or Fittings are placed along the Section.

FLIP causes the settings of the following pairs of attributes to be exchanged:

•

POSS and POSE (Start and End Positions)

•

DRNS and DRNE (Start and End Plane Directions)

•

JOIS and JOIE (Start and End Joint References)

Note:

It is not intended that Sections with secondary connections be Flipped, although its possible if the user fully understands the effects outlined below. These effects may not give the results intended and may therefore require further design modifications to be made:

The settings of the SREL and EREL (Start and End Release) attributes are not exchanged. Since, however, the ends to which they refer have changed (since the original Start is now the End, and vice versa), their effects will be reversed in the physical model.

•

The Member List of the Flipped Section remains unchanged, so that any cross-references to member elements by list position remain correct. The ZDIST attributes of any SNODs, FITTINGs, etc. remain the same, so that their positions are now derived from the opposite end of the Section (the new Start end), thereby causing these member elements to move.

•

Any Connected items referenced via SJOIs will not move, since the positions of the corresponding SJOIs will not move to the new SNOD positions until they are Disconnected. To reverse a Section with existing secondary connections the user should, therefore, use the following sequence of operations:

•

Disconnect the Section to be Flipped from all attached Sections.

•

Flip the Section, thereby repositioning all of its SNODs and their associated SJOIs (now disconnected) in the reversed locations.

•

Reorientate all connected Sections so that they realign with the modified SJOI locations along the Flipped Section (or reset the ZDIST attributes of the SNODs so that they are repositioned where required).

•

Reconnect the Flipped Section to all the attached Sections.


Example:
FLIP	Reverses the Start and End attribute settings for the current element as outlined in the preceding description.

Command Syntax:

>--- FLIP --->

Querying:

The following querying commands, used both before and after giving the FLIP command, maybe helpful in checking the precise effects of the command:


Q ATT	For checking, in particular, all Start and End related settings (POSS/POSE, DRNS/DRNE, etc).
Q DER POS	For checking the derived positions of SNODs and/or SJOIs.