topic Re: Update Block Definition without ATTSYNC in Visual LISP, AutoLISP and General Customization Forum

Update Block Definition without ATTSYNC

Fredrik.Karlsson2VZLJ — Thu, 30 Oct 2025 11:07:20 GMT

I have the need to change the layers of the genometry inside a block definitions in order for the blocks to work with vpFreeze. The provided code works but I have to run ATTSYNC, which I can not do because all, or most, at least in my case, attributes will be returned to the orginal position which creates a way to big of a problem. How can I, if it is even possible, update the Block Definiton via the code so I dont have to use ATTSYNC?
Im using AutoCAD Lt 2024, and the blocks that are subject for this code contains attributes and visiblity states. An example block is providede in the attached dwg file. To clearify I am a noob in terms of AutoLisp but half decent AutoCAD user.

Update 2025-10-30:
Doing the same thing by going into the block editor for each Block Def. and changing the genometry layer works just fine without ATTSYNC

Re: Update Block Definition without ATTSYNC

Moshe-A — Thu, 30 Oct 2025 11:20:51 GMT

@Fredrik.Karlsson2VZLJ hi,

BATTMAN (or ATTSYNC) command update only the attributes of block (and that's include attributes position)

where the BEDIT (Block Edit) command, handles the block definition (geometry). inside Block Edit session you can change the attributes but as you exist, the update process (regen) does not touch the attributes only BATTMAN (ATTSYNC) does that.

Moshe

Re: Update Block Definition without ATTSYNC

Fredrik.Karlsson2VZLJ — Thu, 30 Oct 2025 12:11:43 GMT

So when the block editor exits it runs regen?

Re: Update Block Definition without ATTSYNC

Moshe-A — Thu, 30 Oct 2025 12:47:47 GMT

YES and only the block geometric is update.

this behavior is known in AutoCAD since it's born (previous century around 1982) 😀

and why is that?

in these old days attributes where the only way to store textual data in a drawing to create BOM (Bill of Materials)

(no xdata, no Extended Data no Dictionaries where around) so careless Automatic updating blocks could led to disruption of BOM

so AutoCAD gave us BATTMAN\ATTSYNC command to handle attributes separately and even today these commands

does not touch the attribute value (only the graphics properties e.g position, layer, color, text size, text style and text angle.

Moshe

Re: Update Block Definition without ATTSYNC

paullimapa — Thu, 30 Oct 2025 19:12:53 GMT

Perhaps we can all gain some insight from the code in the free open source AttRedef.lsp packaged with AutoCAD since Release 10.

I briefly introduced this in my first Free Samples article here:

AUGIWORLD by AUGI, Inc. - Issuu

Re: Update Block Definition without ATTSYNC

Fredrik.Karlsson2VZLJ — Mon, 03 Nov 2025 10:10:23 GMT

I tested doing REGEN and REGENALL manully and also adding (vla-regen doc acAllViewports) and the end of of the function, that moves the block geomentry to another layer, but nothing I tried works. I still cant get the block genometry to be frozen when the layer is frozen.

Is it possbile using LISP to redefine the blocks from the tool palette which is the idea anyways?

Re: Update Block Definition without ATTSYNC

Moshe-A — Mon, 03 Nov 2025 10:46:44 GMT

@Fredrik.Karlsson2VZLJ ,

@Fredrik.Karlsson2VZLJ wrote:
I tested doing REGEN and REGENALL manully and also adding (vla-regen doc acAllViewports) and the end of of the function, that moves the block geomentry to another layer, but nothing I tried works. I still cant get the block genometry to be frozen when the layer is frozen.

Is it possbile using LISP to redefine the blocks from the tool palette which is the idea anyways?

first you say it works

next it does not

Editing the block with BEDIT than exit using save will drags auto regenerating drawing which update all that block references (but not the attributes)

if in BEDIT you changed an object layer (not attribute) this will reflect after regen. any object on frozen\off layer will be hidden.

does that more clear?

Moshe

Re: Update Block Definition without ATTSYNC

Fredrik.Karlsson2VZLJ — Tue, 04 Nov 2025 06:35:18 GMT

What works is that the LISP function moves the geometry to another layer, i.e. MyLayer. When the function is done and when you freeze the layer, in this case MyLayer, the geomentry does not get frozen.

Doing the same thing, on the same block, in the same drawing, manualy, meaning going into the block editor, selecting the geometry and changing its layer, exiting the block editor, and then freezing the layer, in this case MyLayer, freeze the geometry works as intended, meaning the manual way works, the Lisp function does not.

After some more testing it seems to be related to block references meaning blocks with a, as i understand it, hidden name like *U310

Re: Update Block Definition without ATTSYNC

truongyen2442y — Tue, 04 Nov 2025 06:09:47 GMT

If you're only changing layers of block geometry, just:

Use BEDIT
Change the layer of geometry
Save and exit
No need to run ATTSYNC, and no attribute positions will be disturbed.

Re: Update Block Definition without ATTSYNC

Moshe-A — Tue, 04 Nov 2025 10:33:26 GMT

@Fredrik.Karlsson2VZLJ ,

i think i have it 😀

your problem is with this block reference \ insert, delete it and reinsert

changing a dynamic block after creation some times have problems with the already inserts

Moshe