A DXF question, are anonymous blocks simply blocks not named by the user?

[oransen]

I could not find a DXF group, so thought this was the best place to ask...

Are anonymous blocks simply blocks not named by the user? Maybe created by an application?

The DXF manuals repeatedly say the same phrase about hatching and dimensions etc, but I've found many DXFs with anonymous blocks (flagged and /or starting with *) which seem to have nothing to do with hatches or dimensions.

Does "anonymous" simply mean "automatically named", or is it deeper?

[artc2 · Accepted solution]

Yes, that's pretty much it.  Anonymous blocks can be created by any application.  AutoCAD itself uses them for a number of things in addition to hatches and dimensions.

[oransen]

Thanks for that!

I've been digging deeper, if you have any comments on this please do...

It seems that "named blocks" are always in lower hierarchy first, so a block cannot itself INSERT an undefined block.

But I've found a DXF file where *U1 is defined before *U2 and *U3, but *U1 has inserts of *U2 and *U3.

So, in DXF files, can anonymous blocks be "inserted" before they are defined...?

[artc2]

You can't create an insert that references a block that isn't yet defined.  But, you can change an existing insert entity to reference a different block than the one it started with.  You can also change the contents of an existing block, so you could add inserts into the first block after the other blocks have been created.

[oransen]

I was thinking more of the internals of DXF files rather than the user doing it. Anyway, some DXF files have that structure of using *U2 in *U1 and only defining *U2 after *U1, so I'll have to deal with it 

Thanks for the pointers