Using library items

[spectric]

Hi all

If you have items in the library and import one into a drawing it has a block reference, so you cannot modify it without changing other drawings that reference this block. Can you import it as an individual entity and make it a new block only relevant to this drawing?

thanks Roy

[CVH]

Hi,
I think you are wrong.
Referring to:
https://www.qcad.org/rsforum/viewtopic.php?f=32&t=7422
A library item is inserted as a block definition and a block reference.
And left there as it was.
You can edit that block the same as any other block and it is no longer related to the library items.
So, the inserted block definition is as individual inside a document as can be.

To get the individual entities and loose the block reference you can select and 'explode' the block reference.

Regards,
CVH

[Husky]

Hi,

If you have items in the library and import one into a drawing it has a block reference, so you cannot modify it without changing other drawings that reference this block.

Your inserted Block (Library item) will not have a backwards connection to the Library.
With other words: Changing an inserted Library item in a drawing will not change the in the Library stored Block or other drawings where the item was used.

Can you import it as an individual entity and make it a new block only relevant to this drawing?

Yes.
After inserting it is already only relevant to this drawing. You can duplicate it ... or explode it at all, change it, store it as a new block etcetc

If you need to use it also as a Library item in other drawings ... store it in the Library too.

[spectric]

Hi all

That makes sense, the library items can only be changed directly and there is no risk of unwittingly altering other drawings that reference that part, which is what I was concerned about. I have realised that the explode block command is basically ungroup.

thanks Roy

[CVH]

other drawings that reference that part

Again, there is NO reference to the library parts ...
Think of them as wizards, stencils, stamps, predrawn artifacts, ...
of what you place a plain copy in the drawing.
Mostly as a one reusable block, a few generate basic entities.

I have realised that the explode block command is basically ungroup.

A block is not just a group.
Explode (XP) has more functionality than just 'ungroup'.

Regards,
CVH

[Rantanplan7]

Hi all,
for me it was a bit painful to learn and understand that every CAD drawing has it's own block / symbol table in the background.
When you have a library and you change a block of your library without changing the name of it you are in trouble.
You open an old drawing which has this block on it and you want to add a next one from the library it would not work as QCAD would just add a copy of your existing old block and you wouldn't get your new version of that block.
Even more tricky to understand why, is if your old drawing had this symbol, but you have deleted it. It is still in the block table in the background unless you purge unused blocks and will still stop you from getting the changed block version in your drawing.

[Rantanplan7]

Another question regarding blocks and libraries.
I have just spotted that one library item has two names - or at least it looks like that.
One explanation would be, that QCAD stores the last name in it....?
Example is in the attachment.
Two items from my library, a left corner piece and a right one. Now the strange thing is, that the left one has two names.
If you open the attachment and if you make item 33 invisible in the block list, the left corner disappears as expected. If you make 34 invisible, they both disappear....but why? If you delete the right one and purge unused blocks, the right one is gone but the name stays in the block list...

[CVH]

Hi,
Block33 is a flipped copy of Block34.

Edit Block33 and see that it is Block34 flipped over.
Select & Explode this 34 Block inside the 33 Block and they are no longer linked.

Regards,
CVH

[Rantanplan7]

Ok, that makes sense. Thanks.
Sometimes a bit tricky to spot the hidden secret behind things.

[CVH]

I would leave it like that.
Editing one master is less work.
(Edit: If you know there is one)
CVH

[Rantanplan7]

Yes. I was just a bit surprised about the behaviour. In general I don't care unless it causes some trouble in the future - like the missing unit on library items.