Changing the Structure of the List Blocks (SAP Library

Changing the Structure of the List Blocks

Use

The drawing BOM blocks used by AutoCAD are blocks that comprise several sub-blocks (a basic block and several row blocks). AutoCAD uses several lists, each structured on the same principle. For example:

Itemized BOM (GENBPOS, GENTPOS)
Summarized BOM (GENBSUM, GENTSUM)
Coordinates list
Adjustment list

If you use one of the standard AutoCAD drawing blocks as a copy template, and want to give this block a different name, you cannot merely rename the *.DWG. The block name, footer block, and the row blocks must all have the same name (plus the corresponding sequential number). Therefore, always open, rename, and close the blocks in the block editor. If you do not, an error message will be issued when you go to output the BOM.

Names and Structure of List Blocks

The names of the sub-blocks (row blocks) are formed by taking the name of the main block and appending a whole number to this name.

If the main block is called RONNI, the basic block must be called RONNI0, the first row block RONNI1, the second row block RONNI2, and so on. In this section, the itemized BOM block GENBPOS will be used as an example in order to clarify this.

The sub-block that contains the footer (i.e. the list header) starts with the number 0 (in our example, therefore, this is GENBPOS0).

This sub-block is inserted only one at the beginning of the list (or, if there is a page break, at the beginning of every new page). This sub-block is not assigned to a data record. The footer block contains reference texts for a specific message file.
When the BOM is being structured, the appropriate designations are retrieved from the file GENDWG.MLD, and inserted in the footer block. These designations in the footer block provide comments for the various list lines. AutoCAD uses this procedure because it is language-independent. There would be no problem in replacing such a text (e.g. genmsg "gendwg" NrX) in the block with a fixed designation.

The remaining sub-blocks (i.e. the row blocks) read specific data from the appropriate data record to their attributes (e.g. 5GENST).

Generally speaking, every sub-block is represented by one "data row". The names of the sub-blocks must be formed by appending a sequential number to the end of the block name. The first number in the sequence must be 1.
One record from each of these sub-blocks is inserted per data record in the list. If the data record does not contain any information, the block in question can be suppressed ("Suppress empty line sections" option in BOM dialog box) – i.e. it is not inserted. If this were not the case, the BOM might contain a series of empty lines.

Inserting List Blocks

When inserted in the drawing, a list is inserted row by row (Y-axis-oriented). The BKS must be oriented in the same direction in which the list or table is to be created. In principle, the list block can be inserted anywhere on the screen. The values determined by the program for the attributes in the sub-blocks are written to the list.

The sub-blocks are inserted in the same direction as the list is structured, and in ascending order (starting with sub-block 1).
A list can be structured starting at the bottom and working up (e.g. GENBPOS); or by starting at the top and working down (e.g. GENTPOS). This will depend on the insertion points of the blocks in question. The sub-blocks are inserted in the main block in the same way as they are organized in the normal list structure. The insertion points of main block GENBPOS and sub-blocks GENBPOS1, GENBPOS1, ... are arranged vertically on top of each other.
The insertion point of the main block is the bottom right-hand corner of the main block (i.e. also the bottom right-hand corner of the footer block). You specify the insertion point for the main block when you insert the list manually in the drawing.
The insertion point of the sub-blocks is the top right-hand corner of the block in question.

Transferring Data to List Blocks

The data that comes from the *:TXT file is separated into the corresponding data fields as defined in the *.DSK file.

First, an attempt is made to insert the bottom row block (i.e. GENBPOS1) in the drawing.

When the block is being inserted, the data is assigned to the various attributes of the BOM block (i.e. the value of the attribute 3GENPOS, for example, is written to 3GENST, etc.).

If no data is available for this row block, the insertion process is suppressed for the row block unless you have specifically stated that empty lines should be inserted.

Next, the same procedure is followed for the blocks GENBPOS2 and GENBPOS3.

The first data record has now been processed. The same process now starts for the next data record, and continues until no more data records are found in the *.TXT file.