Defining the Obstruction List

Keywords

OBSTRUCTION EXCLUDE REMOVE

Description

The list of obstructions, defining those items in the spatial map against which clashes are to be checked, may be built up in stages. To add items to, or remove items from, the current list in any of the following ways:

• By adding one or more specified Design elements

• By adding implied tube or rod between piping or structural components

• By excluding one or more members owned by elements in the list

• By removing items from the current obstruction list and/or from the current exclusion list

  Note:
  The current obstructions and exclusions are stored as two separate lists, the effective obstruction list being the difference between the two. The OBSTRUCTION and EXCLUDE commands add specified items to those lists, but do not overwrite any existing contents. To remove items from the obstruction and/or exclusion lists, the user must do so explicitly and separately for each list by using the REMOVE command.

When adding any element to the obstruction list, all elements and primitives below the specified item (that is, all of its members) are automatically incorporated into the list. By default, the obstruction list contains all design elements in the current MDB.

If a Branch (or higher) element is added to the obstruction list, implied tube within the Branch is treated as part of the obstruction. If, however, individual piping components are added to the list, implied tube connected to those components is not included automatically and must be added specifically if required. The same principles apply to implied rod, and also to implied tube or rod within Groups.

Only items that have previously been added to the obstruction or exclusion lists may be specified in a REMOVE command. Removing an obstruction does not automatically remove any exclusions which were specified when that obstruction was added to the list.

Command Syntax

                              .-----<------.
                             /             |
>---+--- OBStruction ---+---*--- <clid> ---+---.
    |                   |                      |
    |                   ‘--- ALL --------------|
    |                                          |
    |                         .-----<------.   |
    |                        /             |   |
    ‘--- EXClude -----------*--- <clid> ---+---+--->

>--- REMove ---+--- OBStruction ---.     .-----<------.
               |                   |    /             |
               ‘--- EXClusion -----+---*--- <clid> ---+---.
                                   |                      |
                                   ‘--- ALL --------------+--->

where <clid> (clashing item identifier) is

>---+--- ILEAve ---.
    |              |
    |--- IARRIVE --|
    |              |
    |--- HEAD -----|
    |              |
    |--- TAIL -----+--- TUBe ---.
    |              |            |
    |              |--- ROD ----|
    |              |            |
    |              ‘------------+--- OF -----.
    |                           |            |
    |                           |--- FROM ---|
    |                           |            |
    |                           |--- TO -----|
    |                           |            |
    |                           ‘------------+
    |                                        |
    ‘----------------------------------------+--- <gid> --->

Querying