Auto-Number Block Attributes in Multiple AutoCAD Drawings — Sequential Tags Like V-001 to V-028 with Excel

Open BlockSync and add the drawings with Add Files… or Add Folder…. BlockSync scans each file and lists every block definition it found, with how many times it is referenced and in how many files. Here VALVE has 28 references in 6 files.

Tick the block on the Blocks tab and click Extract to Excel. Only ticked blocks are exported, and each one becomes its own tab in a timestamped workbook in the output folder shown on screen.

The B_VALVE tab has one row per block reference, drawing after drawing. On the left are the system columns, the file name and the object handle that BlockSync uses to find each block again. On the right is one column per attribute tag. Here every valve still has TAG V-000, and the numbering will follow the order of these rows.

If you want a different order, sort the sheet first. Every row carries its own file name and handle, so rows can be sorted freely as long as you keep each row together, for example by drawing and then by the PosX column to number from left to right.

TAG is column M in this sheet and the first block is on row 3, so select M3 down to the last row and enter ="V-"&TEXT(ROW()-2,"000") in every cell of the range. ROW()-2 gives 1 on row 3, 2 on row 4 and so on, and TEXT(…,"000") pads it to three digits, so the sequence runs V-001, V-002, and continues through every drawing to V-028.

To restart the numbering in each drawing instead, use ="V-"&TEXT(COUNTIF(A$3:A3,A3),"000"). Column A holds the file name, so the count begins again at 001 whenever the drawing changes: V-001 to V-005 in the first drawing, V-001 to V-004 in the second. Change the prefix or the number of zeros to suit your tag standard. BlockSync writes back what the cell displays, so a formula is fine.

Save the workbook, in the same folder as the drawings if you can.

Switch to the Excel → AutoCAD tab and pick the workbook. With Same folder as Excel file ticked it looks for the drawings next to it and matches them by file name, and each row is matched to its block by file and handle. Leave Automatic backup checked.

The Diff preview reports 6 files previewed, 28 attribute changes and 0 blocked. Select a drawing to see each change: in PID-01 the TAG attribute of the five valves goes from V-000 to V-001, V-002, V-003, V-004 and V-005. Nothing is written until you confirm.

Click Write Selected Files and confirm. BlockSync backs up each drawing, writes it, then reads every changed attribute back out of the drawing. The results screen reports 6 succeeded, 0 failed and 0 read-back mismatches, and shows where each backup went. Rollback All puts every drawing back as it was.

To check it independently, export the drawings again. In this example the TAG column read V-001 to V-028 in order across the six drawings, and MODEL still said TBD, because only the changed attribute is written.