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 reorienting a Section with a non-symmetrical profile if you have 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 you can do so if you fully understand the effects outlined below. These effects may not give the results you had 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, 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. If you wish to reverse a Section with existing secondary connections you 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.

• Reorient 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 you want them).

• 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:

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