Topic: Blocks

[HarleyHetz]

I run AutoCAD 2K6 at home, and 2K2LT at work. I was talking to a friend yesterday who draws schematics for a living, he was helping me with a "block" question, and he said something that got me to thinking, so I figured I'd get some second opinions.
He told me that he saves his blocks as a drawing file instead of as a block. He says that makes them more managable. That if you want to change a "block", you pretty much have to explode it, make whatever changes you want, then resave it. Whereas if you save it as a drawing, you can open it anytime you want, change it, save it as a new version, or write over the old version. (Doesn't seem like that much difference to me??)
But the question I have is how does this affect the overall drawing size when you are using many blocks inside of a single drawing. Does it use more memory to put a bunch of "drawings" into your drawing as blocks as opposed to putting "blocks" into your drawing as blocks???  :ugly:

[Arizona]

I'll attempt an explanation of this one
By saving the blocks as separate dwg files he is probably able to manage this block library better because he can use file management to sort these blocks/dwgs into logical folders.
When you simply store them in a dwg you have no way of managing the separate blocks since they only exist as part of another drawing.
The way the autocad handles a block is:
The block definition is non-graphical information contained within the dwg and only exists once.
Block references are the graphical piece. There may be many references referring back to this block definition. When you update the block definition all references to that block are updated as well.
So whether you store a block within a file or as an external file has no real revelance to the file size unless you are storing unused blocks in a drawing in which case you are doing yourself a dis-service.
Did I confuse you?

[CADaver]

Once a "drawing" is inserted in a file, it becomes a block, so there shouldn't be any file size difference.
We use separate drawings because they are much easier to manage and update when necessary, and when inserted don't carry any additional baggage of unused blocks.

Blocks do not have to be exploded to edit, check out REFEDIT on blocks.

[Kate M]

I used to use the "separate drawing" method, prior to Dynamic Blocks. Now, I find DB's are much easier to manage if they're already in a "container" drawings, and since we only access them through Tool Palettes, they don't bring any unwanted content with them.

When the blocks were in their own drawings, they were stored in exploded form to avoid "block references itself" errors.

[craigr]

Not to steal this thread, but....

We (almost) ALWAYS explode our blocks, once we insert them into our dwgs. - I thought everyone does this, (?).

By exploding the blocks, we remove any references within them once we purge, right?

Is this a 'normal' process to explode the purge every block?

craigr

[Arizona]

Not to steal this thread, but....

We (almost) ALWAYS explode our blocks, once we insert them into our dwgs. - I thought everyone does this, (?).

By exploding the blocks, we remove any references within them once we purge, right?

Is this a 'normal' process to explode the purge every block?

craigr

This would certainly increase the file size!
If a drawing containeda block with 6 instances of a block reference inserted in the drawing. Then what is being stored is one block definition (non-graphical) and 6 (graphical) block references (pointers to block def.). When you explode these (block references) back to entities each entity is stored individually, so this would increase the drawing approx. 6 times, even after purging.

[craigr]

This would certainly increase the file size!
If a drawing contained a block with 6 instances of a block reference inserted in the drawing. Then what is being stored is one block definition (non-graphical) and 6 (graphical) block references (pointers to block def.). When you explode these (block references) back to entities each entity is stored individually, so this would increase the drawing approx. 6 times, even after purging.

That makes sense to me but we explode blocks that almost never have any blocks within blocks, so when we explode then purge them, they are no more than lines, circles, etc....

I have always figured this was a much 'cleaner' way of finishing the dwgs - nothing hidden to cause problems later.

No problems, right?

What would be the advantage of not explode / purging them?

craigr

[CADaver]

We (almost) ALWAYS explode our blocks, once we insert them into our dwgs. - I thought everyone does this, (?).

AAACK!!!  May a herd of Yaks infest your lower colon.

Using blocks for repetative elements reduces files size, sometimes drastically.  A steel structure using unit blocks for the members may have a file size of 300K while the same file using 3Dsolids would be 2MB.

Blocks, even without attributes, can be extracted into intelligent data.  The unit blocks in the structure above can be extracted, using LISP, and the length of each beam (X scale) and height of each col (Z scale) can be multiplied by the member weight (number following the "x" in the block name) for a quick material weight.

Adding attributes to blocks allows a much greater degree of intelligence extraction using tools like EATTEXT.  Simple things like furniture can carry a manufacturer's part number, location, phone number, or anything else you may need.  A manager can then extract the data and find any piece of furniture he likes.

Simple blocks like section marks or detail bubbles can be quickly redefined to match client standards, and updated over an entire directory in minutes.

Exploding blocks around here will get you "knee-capped"

[Krushert]

AAACK!!!  May a herd of Yaks infest your lower colon.

Exploding blocks around here will get you "knee-capped"

Around here you will be fed to the lobsters,  ... ALIVE

But hey; all kidding aside, to each their own.   

[CottageCGirl]

We never explode, because we generate an excell spread sheet from the block attributes....but I tried a test and a drawing with over 750 small blocks (3-10 attributes each) the drawing went from 925 KB to 1.08 MB after exploding......

[craigr]

I would think it depends somewhat on your industry. Ours is HVAC Building Automation & most of our dwgs consist of line / wiring diagrams. Blocks that we do not explode are as examples - a wiring terminal, Ground symbol, small things like that. Everything else is exploded.

Our blocks do not contain any of the info you folks mentioned, hence no info to lose.
The parts we supply for a system have the part number listed on the dwg with the devices.

   For our Security projects, I have gotten floor plans from outside firms that have furniture in them that are blocks which may have some of these attributes you mention - I explode all of them & put them on a layer called 'furniture'. I have no use for this other info. I basically just want a layer for all of the furniture & such, then isolate it from the walls, doors, windows & such - which go on a layer called 'floorplan'. I often have to do quite a bit of exploding & erasing to get everything isolated & on their own layers. The floor plans are copied into our title block and retained by us. The info that I am purging would not be missed for our purposes.

craigr

[CADaver]

I have gotten floor plans from outside firms that have furniture in them that are blocks which may have some of these attributes you mention - I explode all of them & put them on a layer called 'furniture'.

You've probably doubled or tripled the file size

[dan19936]

   For our Security projects, I have gotten floor plans from outside firms that have furniture in them that are blocks which may have some of these attributes you mention - I explode all of them & put them on a layer called 'furniture'. I have no use for this other info. I basically just want a layer for all of the furniture & such, then isolate it from the walls, doors, windows & such - which go on a layer called 'floorplan'. I often have to do quite a bit of exploding & erasing to get everything isolated & on their own layers. The floor plans are copied into our title block and retained by us. The info that I am purging would not be missed for our purposes.

I'd use layer translator instead of exploding. Just select all the offending layers and put it on furn or layer zero.

Dan

[MickD]

the beauty of blocks is you only store the information to create them once (a block def) and all graphical info you see on screen ref's this definition to draw it, all it needs is the rotation and scales to be stored in the dwg file.

for example a block definition may look like this -

line y,y,z,...(info about line)
circle ...
etc, may be many many more graphical items.

a ref would look something like this -
blockref -
insert name (used to reference the definition)
insert position
rotation
scale x,y,z.
(perhaps a little more info)

so when it comes down to it, it doesn't need to store 'all' the graphical object info in the dwg file for every block, only the bare essentials to insert and place the block whose info is stored in the one definition.
If you explode them it will create graphical entities for each block ref and they will need to all be stored as simple objects thus increasing file size.

[Bryco]

Not sure if I read that right. I've never used Lt.
In Lt you can make a block but not refedit it?