What is Layer "0" and Layer "Defpoints"?

Just wondernig the purpose or intent of these layers? Do they have any additional features when compared to any other layer that I might create on my own? Is there some standard info that others may expect to find on these layers when I begin sharing my drawings with customers or suppliers?

As soon as you add one dimension to a drawing AutoCAD will create the Defpoints layer. Anything on that layer will not plot.

Layer "0" is just a default layer. The caveat has always been to not put anything on layer 0. It is also said that this is the layer one should create blocks on so that upon insertion into other layers the blocks will assume the properties of the layer (color, linetype, etc.). Of course most newbies draw everything on layer 0 and then compound the error by overriding settings for color and linetype thus creating headaches for others who know better. When I receive a drawing like this from an outside source I know it is going to be a long, long day and I break out the large bottle of aspirin.

I wrote this 1 a while ago. Maybe it will help some. -David

http://www.cadtutor.net/forum/showthread.php?t=2824&highlight=Layers

paulmcz, you do not have permission to access this page. This could be due to one of several reasons:

 

1. Your user account may not have sufficient privileges to access this page. Are you trying to edit someone else's post, access administrative features or some other privileged system?

2. If you are trying to post, the administrator may have disabled your account, or it may be awaiting activation.

Why am I getting this message when I click on the link David posted?

Why am I getting this message when I click on the link David posted?

http://www.cadtutor.net/forum/showthread.php?t=2824

No, I am getting exactly the same message from your link.

I don't have that problem. Is this any better?

 

http://www.cadtutor.net/forum/showthread.php?t=2824

I seem to get the same message as well.

As soon as you add one dimension to a drawing AutoCAD will create the Defpoints layer. Anything on that layer will not plot.

 

Layer "0" is just a default layer. The caveat has always been to not put anything on layer 0. It is also said that this is the layer one should create blocks on so that upon insertion into other layers the blocks will assume the properties of the layer (color, linetype, etc.). Of course most newbies draw everything on layer 0 and then compound the error by overriding settings for color and linetype thus creating headaches for others who know better. When I receive a drawing like this from an outside source I know it is going to be a long, long day and I break out the large bottle of aspirin.

The noted Information by Mark seems to be EXACTLY the same as at another Acad Web-site. I go near no place with the linked forum note too. Must be something hay-wire.

I think Layer zero is related to the BASE coordinates for the drawing, and XREF'd ones, and the same drawing being used as an XREF in another drawing, for near everything then registers and aligns to it.

Is very difficult to get rid of any inforation on defpoints layer, and then PURGE it out.

Wm.

It probably has something to do with it is in an archive section of the forum.

General concepts and good drawing practice - Layers

*** Concept:

What is a CAD Layer?

The best analogy I know is to think of an overhead projector with transparent

overlays. Each overlay represents a layer that can added or removed at will.

By stacking one on top of each other or layered if you will, you can show or

hide the layers as needed. CAD programs give you the ability to do this in a

virtual world.

The Basic Layer States:

Freeze/Thaw

Thaw - Everything on this layer is visible and plotted

Frozen - Everything on this layer is NOT visible and NOT plotted

Visibility

ON - Everything on this layer is visible and plotted

OFF - Everything on this layer is NOT visible yet plots as though they were ON

Protected

LOcked - Everything on this layer is protected from editing

Plotting

Plot/NoPlot - Introduced after 2000.

OFF vs Frozen

Even though entities residing on layers that are turned OFF

ARE NOT visible on the display screen:

They ARE considered with the follow commands and values:

HIDE ( including plots ), EXTENTS ( including ZOOM ), REGEN

They ARE NOT considered during:

SHADE, RENDER, FILL

Entities residing on layers that are Frozen ARE NOT considered

in any of the mentioned actions.

You can independently Freeze layers in paperspace viewports. The layer must

be Thawed and ON to do so.

*** Naming Conventions:

CAD programs allow you to use the alpha numeric characters and the

special characters dollar sign ($), hyphen (-), and underscore (_) for

layer names. It does not allow you to use extended ASCII characters

or the special characters that are reserved for wildcard searches.

### COMMENT: There was once a 31 character name length limit. It is still

a good rule to abide by. Backward compatibility, a lot less typing,

cleaner screen readability to name a few.

*** Reserved Names:

0 and DEFPOINTS are reserved layer names used in CAD programs. They

have some preset and sometimes quirky rules that go with them.

Layer 0 is always present and cannot be purged. Entities created

on layer 0 and incorporated into a BLOCK, will take on the INSERT

layers properties unless you override the entity properties for COLOR,

LTYPE, LTSCALE.

Layer DEFPOINTS is automatically created when creating a DIMENSION

entity. It contains the DIMENSION entity definition points. Entities

on layer DEFPOINTS are never printed. Even when the layer is turned OFF,

entities on layer DEFPOINTS are visible on the screen.

Layer ASHADE is a layer added during a render process. It has standard layer properties as far as I know. It is creating in the OFF and LOcked mode, but can be changed.

!!! Good Habits:

Be as consistent as possible when creating your naming conventions. Some

disciplines use a very strict and detailed layer naming convention. Some

of these make sense, some are a bit more cryptic.

Misspelled names can lead to a lot of confusion.

Watch out for the old zero vs O mixup. Fonts and video drivers can make hard it to

distinguish between the two.

Use consistent prefixes and suffixes when possible. These can be used in

conjunction with wildcards searches for some very efficient layer control

using the command line version of the LAYER command. It even can help

with the dialog box interface.

### COMMENT: I highly recommend that cadders learn the command

line version of the LAYER command. It will surprise a lot of people how

much faster and easier basic freeze/thaw operations are when used on the

command in conjunction with a good layering name convention. The dialog

box is better for editing layer properties.

### EXAMPLE:

This is a sample of a layering convention we use:

Command: -la
-LAYER ?/Make/Set/New/ON/OFF/Color/Ltype/Freeze/Thaw/LOck/Unlock: ?

Layer name(s) to list <*>:

   Layer name       State       Color       Linetype
------------------ --------- ------------- ------------
0                  On          7 (white)   CONTINUOUS
1D                 On         10           CONTINUOUS
1D-WALL            On         11           CONTINUOUS
2D                 On         14           CONTINUOUS
2D-DOOR            On          1 (red)     2D-DOOR

3D-7               Frozen      7 (white)   CONTINUOUS
3D-ALUM            Frozen      4 (cyan)    CONTINUOUS
3D-BRUSHED         Frozen      2 (yellow)  CONTINUOUS
3D-CASTIRON        Frozen      5 (blue)    CONTINUOUS
3D-CHROME          Frozen      7 (white)   CONTINUOUS

3D-COLDROLL        Frozen      7 (white)   CONTINUOUS
3D-DOOR            Frozen     15           CONTINUOUS
3D-DOOR-CH         Frozen      7 (white)   CONTINUOUS
3D-EPOXY           Frozen      3 (green)   CONTINUOUS
3D-GLASS           Frozen      3 (green)   CONTINUOUS

3D-PLAM            Frozen      5 (blue)    CONTINUOUS
3D-PLAM-BODY       Frozen      4 (cyan)    CONTINUOUS
3D-PLAM-SUP        Frozen      4 (cyan)    CONTINUOUS
3D-SAFETY          Frozen      7 (white)   CONTINUOUS
3D-SOLID           Frozen      3 (green)   CONTINUOUS

FS-EL              Frozen      1 (red)     CONTINUOUS
FS-FACE            Off        12           CONTINUOUS
FS-GA              Frozen      2 (yellow)  CONTINUOUS
FS-PL              Frozen      5 (blue)    CONTINUOUS
FS-RF              Frozen      7 (white)   CONTINUOUS
FS-VT              Frozen      6 (magenta) CONTINUOUS

WALL               On          3 (green)   CONTINUOUS
WALL-COL           On         13           CONTINUOUS

By using wildcards, you can Freeze all of the 3D layers from

the command line by:

Command: -la

Enter an option

[?/Make/Set/New/ON/OFF/Color/Ltype/LWeight/Plot/Freeze/Thaw/LOck/Unlock]: _F

Enter name list of layer(s) to freeze: 3D*

Or Thaw any wall layers:

Command: -la

Enter an option

[?/Make/Set/New/ON/OFF/Color/Ltype/LWeight/Plot/Freeze/Thaw/LOck/Unlock]: _T

Enter name list of layer(s) to thaw: *WALL*

Or LOck all layers starting with 1D or 2D

Command: -la

Enter an option

[?/Make/Set/New/ON/OFF/Color/Ltype/LWeight/Plot/Freeze/Thaw/LOck/Unlock]: _LO

Enter name list of layer(s) to lock: 1D*,2D*

*** Some commonly used command line wildcards:

Asterisk (*) = Match any string. This can be used, before, after or in the middle of the pattern

Tilde (~) = Match anything but the pattern, similar to the boolean NOT function.

Comma (,) = For multiple patterns, similar to the boolean AND function.

You can get very creative with the wildcard scenario and it can be a great

time saver. You can also incorporate these into SCRIPT files for future

and repetitive uses.

-David

Why am I getting this message when I click on the link David posted?

I get the same message when I click on the link.

David and dbroada, you guys are both on the FAQ team which is probably why you can both follow the posted link with no problem and the rest of us cannot. Does the link go to a page in your archives or does it go to a page in the public FAQ section?

Here's the forum path that I see:

-David

That's the beta project area. Anything posted in there will not be available for viewing by anyone except FAQ team members.

An explanation of the Defpoints layer...

http://autocad.wikia.com/wiki/Defpoints_Layer

Saw this over at Ellen Finkelstein's website re: Layer 0.

Is very difficult to get rid of any inforation on defpoints layer, and then PURGE it out.

Wm.

Even when the layer is turned OFF, entities on layer DEFPOINTS are visible on the screen.

Not true. Defpoints is no different with respect to [on/off] than other layers.

There is a special strange relationship between layer 0 and DEFPOINTS though. Assuming both layers are thawed and ON, if you freeze layer 0, then objects on DEFPOINTS remain visible (as expected), but you cannot select them.

CAD programs allow you to use the alpha numeric characters and the

special characters dollar sign ($), hyphen (-), and underscore (_) for

layer names. It does not allow you to use extended ASCII characters

or the special characters that are reserved for wildcard searches.

 

 

### COMMENT: There was once a 31 character name length limit. It is still

a good rule to abide by. Backward compatibility, a lot less typing,

cleaner screen readability to name a few.

Just an FYI.

The system variable EXTNAMES controls whether or not you can exceed 31 characters and use spaces and other special characters in layer and other table object names. Also, the lisp function (snvalid) can be used to test for valid table names.

David (and all),

Great tips. As a product engineer previously (and not doing any serious CAD work myself), I worked with enough real designers to learn about, appreciate, and understand to a fair extent, the power of layers. So as I start into my role now as product engineer/designer, I am trying to use layers to my fullest advantage and learn all the tools associated with them that are available.

Not true. Defpoints is no different with respect to [on/off] than other layers.

Then that has changed over the years. Pre A2K everything is visible. I did write that a long time ago. -David

Fascinating discussion none-the-less.

I remember using 2007 and if layer zero was frozen you were not able to select the viewport layer if it was on defpoints. Or vice versa. I can't exactly remember.