Anonymous Blocks

Michael Mayer

What is the meaning of ACAD's Anonymous Blocks and their non-editability
in general ?

Like I get (same) Windows via IFC into Bricscad as separate A-Block geometry.
(They are indeed normal copies of Plugin Objects, no Symbol/Block instances,
so still editable together or individually, over there)

1.
To be able to edit them I have to "explode" (one of) them ?

2.
Once I do and create a "real" Block from it,
could I replace the A-Block locations with my new "real" Block or BC Window
XREFs ?

Roy Klein Gebbinck

Anonymous blocks are just containers for graphical entities that are (somewhat) hidden from the user. There can be a lot of them. Every dimension has one, and so does every table and associative array, to mention just a few.

For some reason the _-Rename command does not allow the user to rename an anonymous block, but doing so programmatically is possible. Replacing blocks is also possible.

See the attached (very basic) Lisp code. The commands are RenameBlk and ReplaceBlk.

rkmcswain

I always kind of thought of them as temporary blocks or blocks used by a program that did not need exposed to the user.

I remember about 25 years ago, a co-worker had a routine to make a "group" (I believe this was before AutoCAD groups), and what it was really doing was making the selection set into an anonymous block.

Michael Mayer

Anonymous blocks are just containers for graphical entities that are (somewhat) > hidden from the user

So it is nothing that should contain standard geometry (?)
Is there an example for what this (locked from users) is good for ?

E.g. VW asks me in DWG Export if I want to :
"Convert Groups to Anonymous Blocks"

I see the Windows are Type "Block Reference"
Which do not appear in External References nor in Blocks
of Drawing Explorer.
And it is only when I try to REFEDIT that BC says it can't edit
"Anonymous Blocks" ...

So I think it is because of the way how BIM Windows work.
I now remember a Thread of how to convert these Windows.

Roy Klein Gebbinck

@Michael Mayer:
I do not know VectorWorks. But if a group in that program has editable properties then translating such an object to a DWG block with a fixed name would not be possible. Using anonymous blocks is then a good solution. Using anonymous blocks also avoids name conflicts.

BricsCAD's BIM windows are components. And, indeed, the component mechanism also uses anonymous blocks.

Jason Bourhill

@Michael Mayer said:
E.g. VW asks me in DWG Export if I want to :
"Convert Groups to Anonymous Blocks"

What happens if you don't select this option?

I've seen anonymous blocks from other BIM applications that represent standard geometry such as the columns of the building, or pipe elbows. You can see by viewing the BIM data and check measuring that they are the same components. The worst aspect of this is that the anonymous blocks all have different names, meaning the block definition is created many times making for a large inefficient file. It would be useful if BricsCAD was smart enough to convert these to standard components on import.

If you want to play, Martin Drese previously posted a routine to convert anonymous blocks to named
https://forum.bricsys.com/discussion/comment/32641

Be warned, this will break things if you use on the wrong drawing! Best to used directly after IFC import in a new drawing file.

Workflow to try:

• IMPORT IFC in a new drawing.
• run LISP to convert anonymous blocks to named blocks.
• run BMMECH to convert to an assembly.
• From the Mechanical Browser use options like Switch to external & replace all inserts to clean up the model.

Using the Structure Browser is useful to search through the model.
A lot of IFC imports seem to bring in components like elbows as a faceted solid. Using the technique above you can swap these out for simple solids.

Michael Mayer

Thanks for all your input !

I think this special BIM Window case is exactly what is described in
this Thread :
https://forum.bricsys.com/discussion/33829/assembly-components-not-selectable#latest

BIMINSERT Elements = XREF/Block Mixture
= XREFS that are not in a special separate File but in a Cache
= when editable and edited - convert to a Block
(anonymous Block in my case)

E.g. VW asks me in DWG Export if I want to :

"Convert Groups to Anonymous Blocks"

I do not know VectorWorks. But if a group in that program has editable properties then translating such an object to a DWG block with a fixed name would not be possible. Using anonymous blocks is then a good solution

That was meant independent from the Windows example.
I don't use Groups in VW very often.
I always thought that "anonymous Blocks" in ACAD were just what Groups
are in other Software. (But ACAD has Groups too !?)

I just knew Symbols/Cells/Blocks OR Groups, from the past.

Where a Group is just glueing n*Objects together for Selection and Translations,
behaving just like a single standard Object, saved as completely separate Items
and not connected or parented in any way,
while
Symbols/Cells/Blocks are saved only 1 time in a File Cache/Library and copied
as Instances in a File. Edit one = edit all.

Microstation imported "anonymous Blocks" as "Pseudo Cells" and you also
couldn't to anything with them prior to exploding them.

Roy Klein Gebbinck

@Jason Bourhill:
Interestingly Martin uses a different approach to rename anonymous blocks. He creates cloned copies instead of just renaming the block definition as I do in the example I have posted here. But maybe that is not possible in AutoCAD?

Michael Mayer

For the Windows VW vs BC.

Windows, Doors and such are called PlugIn Objects and are parametrical
Objects that can be inserted and cut into Walls. So similar to BC Windows,
working with constraints.
They can use a Style to fix and centrally edit their common behaviors like
Layers, Jamb and Sash dimensions and so on, while allowing individual
changes like overall Height/Width, number of Sashes and so on.

Therefore you normally just copy them "un-instanced".
You can however put equal Windows into a Symbol/Block as Symbols can
also insert and cut into Walls optionally.
I don't really know what the drawbacks may be for lists, IFC or similar but
you normally would pack them into Symbols only if you have a special
custom Window that can't be done by the parametric PlugIn Tool.
(But It would be possible and save file size though)

So these standard copies of equal VW Windows will come in to BC by IFC
as Window Objects which is fine, but as they work different in VW, it
seems you can't edit them parametrically in any way later in BC.
You can edit some numbers in Property Palette - without any effect or
they just disappear.

For editing imported Windows in BC,
I could replace the imported Windows by other (Windows ?) Objects.
Or
I should try instancing Windows in Symbols in VW, which may allow
manipulating all equal Windows or Doors from a "real" Block.

Jason Bourhill

@Roy Klein Gebbinck said:
@Jason Bourhill:
Interestingly Martin uses a different approach to rename anonymous blocks. He creates cloned copies instead of just renaming the block definition as I do in the example I have posted here. But maybe that is not possible in AutoCAD?

I havn't tried, maybe related to nested anonymous blocks?. In the context of this thread I think your approach is better. With the conversion process you would want to retain the associated BIM data linked to the block.

There is more to it than simply renaming anonymous blocks. This would be ok for standard components with no parameters such as a pipe elbow. For blocks with parameters, such as windows you would want to link them to the core block definition and leave them as anonymous. I think this type of task would be best done as part of the import process.

Regards,
Jason Bourhill
CAD Concepts