blocks-and layer 0-issue

[pvd]

Hi all,

 

why is it that:

 

I make a block and I draw all of it's contents in layer 0.

When finished I put this block on "layer A".

If i turn off "layer A", the block will disappear.

 

I make a block and I draw all of it's contents in "layer B".

When finished I put the block on "layer A".

If I turn off "layer A", the block will still be visible.

 

Anybody?

[designerstuart]

this is the magic of layer 0 - it is special in that it is a see-thru layer

block contents on layer 0 act as if they are on the layer that the block is - hence in your first instance they go off when layer A is turned off.

 

but in the second instance, the entities are on layer B, so turning off layer A has no effect.

 

not completely intuitive, but useful when you can use it to your advantage.

[nestly]

Does Inventor have Freeze/Thaw? If so, can you freeze your layers instead of turning them off? I don't think I've turned a layer "off" for many years.

[designerstuart]

freezing will have the same effect as above. generally i freeze instead of turn off but it's all the same really isn't it? - just a terminology thing i think.

[pvd]

thanks Stuart!

 

So far I can't imagine a situation where I can use it in my advantage but at least I know now.

 

@nestly: I'm an Inventor user but this question concerns Autocad. Thanks for your support.

[danellis]

Not quite. Freezing a layer filters down to affect objects affected by that layer not only those on that layer.

 

Taking the example of a block with contents on Layer B, but the block itself is inserted on Layer A: Turning OFF layer A would leave the contents of the block viisbile, FREEZING layer A would hide the block because that's the layer the block's on.

 

As for ways to use this feature to one's advantage try having a single "door" block (with content on layer 0) and two door layers (perhaps one to represent fire doors and one to represent normal doors). Inserting the single block on each layer would allow one to create drawings showing only certainly types of doors.

 

dJE

[nestly]

freezing will have the same effect as above. generally i freeze instead of turn off but it's all the same really isn't it? - just a terminology thing i think.

 

Off vs Freeze demo

 

http://www.screencast.com/t/DOJypCFkqZ

[designerstuart]

Turning OFF layer A would leave the contents of the block viisbile, FREEZING layer A would hide the block because that's the layer the block's on.

thanks i did not know this. i am also intrigued about this method you mention... i have many times used blocks where you have certain information not showing, but never considered changing the block a layer is on to control its visibility as you mention. could you please give a little more info on how your system works?

 

As for ways to use this feature to one's advantage

i was thinking of the ability to have parts of a block determined by its linework, and parts by the layer it is on. eg. i use section marker blocks where the linework is on layer 0 and the text is in a text layer. this way the line thickness, colour etc can reflect to layer it is on, while the text is always constant.

[Ryder76]

Well...

 

The discussion about blocks on layer 0 is talked about frequently. There are some who think it is a hard and fast rule to draw all blocks on layer 0 with properties all 'bylayer'. I have seen the opposite argued as well, and heard of putting properties 'byblock'. IMHO what is important is that you thoroughly understand how the different ways of drawing blocks affect them. All the different ways are viable and valuable depending on what you need to accomplish. I have blocks that are drawn different ways for good reason, and I like the flexibilty of being able to do it that way.

 

AutoCAD is very complex and subtle which is what makes it so powerful. Just my two cents.

[danellis]

Couldn't agree more.

 

AutoCAD is *not* user friendly, let nobody try to convince you otherwise. AutoCAD *is* powerful, and I know which I prefer (all this because the forum wouldn't let me do a simple QFT!)

 

dJE

AutoCAD is very complex and subtle which is what makes it so powerful. Just my two cents.

[SLW210]

The Layer 0 "effect" on blocks can really allow you to customize your drawings with just a few clicks in some cases. Before Dynamic blocks, you could use this to create different visibility states.