Topic: Help Understanding How Layers can Benefit me

[quamper]

My question is about the use of layers and the importance placed upon them. I'm relatively new in the CAD world (less than a year) having come from an IT background so I don't have alot of CAD experience except what I've been taught by other users at my work and what I've picked up on my own from use and reading. Everything I've read stresses the importance of layers and when talking about CAD standards that's the number one thing I always hear.

I work at a pretty small company with a total of 4 of us using Autocad and there is currently no rhyme or reason for our usage of layers in Autocad for the most part. The only thing we currently use layers for and have set standards is parts that are setup to be cut on our CNC Router as the program that generates the gcode utilizes the layer names for knowing which tooling, cut pattern, speed, etc. However, in our day to day drafting of elevations, sections, etc we very seldom use layers. Realistically most everything is put on layer 0.

My question is why should I use layers? Is there some benefit I'm not seeing that would help me out greatly? I understand if I was working in 3D layers would be critical. However everything we do is 2d and our sections and elevations are pretty well uncluttered, in fact at least a small part of how we get repeat jobs because our drawings look so good and are easy to read/understand (aside from what the quality of what we produce).

My understanding of layers is that they are used for grouping like content to work on independent of other dissimilar items (eg. Walls, Doors, Cabinets,etc). Also for controlling colors/line weights/printing. I understand they have use when using XREF's as well, which we don't use either. We never share the dwgs with other people outside the company as anything that gets sent to a contractor/architect is either printed and bound or pdf so they don't know everything is on the same layer.

We definitely have drawing standards (unwritten but understood and followed) that we adhere to for consistency, but layers aren't part of that. Is there something I'm missing? I'd love to see some real world examples of why layers, especially well named/organized layers help in the drawing process. I'm really interested in anything that we can do to improve our processes and everyone else at my work would definitely be on board with anything I suggest assuming it makes sense.

[Greg B]

Layer's all depend on the company and what they do.

In your case, the drawings stay clutter free and don't require many layers if any at all except 1.

In my case, we do commercial buildings, and we use a fair share of layers.  I keep them easy to read.

N-IntDoor
E-IntDoor
E-Plumbing
N-Plumbing

New and existing.

Easy.

I create a bunch of layers so that I can keep most of my drawing in one file.  So I need separate layers for Reflected Ceiling Plan, Roof Plan, and if I go that far, for multiple levels.

So there is a need for many layers in my case.

[Arizona]

My understanding of layers is that they are used for grouping like content

That is it in a nutshell

Coming from an IT world consider this as just grouped data.
The real benefit comes from what you can do with this data, and the ability to make changes, easily.

[Keith™]

the single most compelling argument for using layers is the ability to create your drawings faster and easier. I know that sounds like a cliche, but imagine you are drawing a widget, not too complex, but it is a single square, octagon or whatever. A single layer would be perfectly acceptable, however, if you imagine that you need to add anything such as holes to be drilled, cut lines, imprint stamps, etc. editing a drawing with multiple objects can become quite the task.
Consider a flat stock object with 32 holes shown. The holes must be moved on the drawing due to improper alignment with another part. You can simply isolate that particular layer and move them. What if you needed to make half the holes a tid bit larger ... sure you could do it easily enough, but if you have layers, you could isolate the circles representing your holes (the 1/2 that needed to be larger) and change them all in the properties manager without having to select each of them independently. Of course this is a simple example. If you were doing complex drawings where one portion of the drawing would overlap another or if you had to do the same drawing as above showing the holes on one page and not on another page, you could easily isolate the holes from the other geometry.
You mentioned you use CNC ... if you detail your drawings on layers other than the layer the object is drawn, you can simply turn off the details and plot the remaining geometry to the CNC with little user interaction. Plus the ability to customize and automate becomes much simpler, as you can then identify programmatically exactly which line represents the south edge and which represents the north edge.

[CADaver]

The more complex the piece the more need for layers.  If you building very simple models you can get by with very few layers.  However, I would avoid using layer 0, it is a special layer with special properties.

What kind of drawings do you guys do? Can you post an example?

[quamper]

Yeah let me find something that I can post...

Can you explain your statement about the special properties associated with layer 0? I know about block's created on layer 0, is there something else? That's the only thing I knew that was special about layer 0.

[architecture68-raff]

My question is why should I use layers? Is there some benefit I'm not seeing that would help me out greatly?

The two biggest benefits I receive from using a well-defined layer system:

1) Easy lineweight control at plot time.  If you need to have varying lineweights in your work, it would be just plain nutty not to use layers.  Combined with good plot styles, you can also easily achieve good-looking plots with a sense of depth.

2)Effective x-refing.  If all your work is on one layer, it makes it difficult to select what pieces of a drawing you want to incorporate into other drawings. 

Perhaps you don't need varying lineweights or fine-tuned xref control.  Not sure what discipline your drawings are, but an hour or two of planning ahead with a layering strategy could save you countless amount of time finagling with things later on.  Regardless, I agree with Randy above that you might not want to use layer 0 all the time.

EDIT: Sorry, should have read your post more closely to see you don't need xrefs.  But if you in the business of creating good looking drawings, you owe it to yourself to look into layers for different lineweights, linetypes, plot styles, etc.

[quamper]

Here's a sample drawing. Somewhat typical.. We do custom cabinets/architectural millwork/etc..

There are quite a few layers in the drawing however most of them are there from pasting in part of the floor plan from the architects provided dwg's where they used layers, or from a few blocks that may have layers set up in them for color's/line types, but that's still rare. If you turn off layer 0 you see pretty much everything is there.

"Effective x-refing.  If all your work is on one layer, it makes it difficult to select what pieces of a drawing you want to incorporate into other drawings. "

We don't currently do any x-refing but the more I think about it that might make sense for us.. All of our sections are stored in one file, then each room get's its own individual file. So where sections need to be reference in elevations I can see how that might benefit us. I'll have to play around with that some.

Thanks for the feedback so far I really do appreciate it.

[Crank]

[...]
There are quite a few layers in the drawing however most of them are there from pasting in part of the floor plan from the architects provided dwg's ....

You don't use layers, but have tons of layer filters imported in that drawing. Use the command FILTERS (acad2006+) to get rid of them.

"Effective x-refing.  If all your work is on one layer, it makes it difficult to select what pieces of a drawing you want to incorporate into other drawings. "

It's also possible to turn off layers for one particular viewport.

Your drawing isn't that complicated, but you can think of special layers for text, hatches and dimensions.
Also special layers for different materials look suitable. If you use different colors for those layers, you can distinguish those materials on screen.

Layers can have different properties: It's possible to draw BYLAYER and use a different layers for different properties. (Do you only use CONTINOUS linetypes?)
Your viewports are draw on a special layer: That is good, but that layer is plotted. Better make that layer unplottable and draw a border on the same layer as your title block. That way you can move your viewports around without changing your modelspace.

[quamper]

Yeah our elevations tend to be pretty basic.. Our sections can get quite detailed though so I see probably a lot more benefit there.

I guess two lingering questions remain for me. It was mentioned that layer 0 was special, other than for block creation is there something else about layer 0 I'm not aware of? And this probably shows my ignorance/n00bness but what exactly are layer filters?

Thanks to everyone for all the feedback so far! It's really been quite helpful in helping me get my mind around all of it

[CADaver]

I guess two lingering questions remain for me. It was mentioned that layer 0 was special, other than for block creation is there something else about layer 0 I'm not aware of?

Elements on layer 0 take on the layer attributes of the target layer when that file is inserted as a block, or xref'd. Layer 0 is also associated with layer defpoints, freezing one of them may cause issues with the other.

Let's look at your sample file, granted it is a very simple drawing but even there we can see some use for layers.  You've gone to the trouble of changing the color of some elements (there are reasons to avoid that as well) that would have been just as easy or easier to change to a different layer.  The first beauty of layers is presetting all the color, linetype, weight, plotability, etc. issues; any element placed on that layer automatically assumes those attributes.  Changing any of those attributes in the layer definition will change all the elements on that layer.  New objects can go from very bold to normal with the click of a single layer's color.

In more complex drawings, it may be easier to see/select a particular assembly with some layers turned off.  Different aspects of an assembly can be shown in different viewports by controlling the visibility of certain layers differently in those viewports.  Example: existing stuff that will be removed, existing room WITH that stuff removed, what the new stuff is, what new stuff looks like installed, all can exist in the same drawing, but be displayed in different viewports.  For presentation drawings the ability to turn off annotation is a definte plus.

When you start XREF'ing a whole new view of layers will emerge (as will avoiding changing the color of elements to something other than BYLAYER)

Here is an image of one of our models, to effectively work on a model that size we employ XREFs extensively, but beyond that elements are separated into layers to help manipulate the model; each pipe is a different layer so that we can extract an iso based on layer, every level of steel is a different layer; equipment, handrail, grating and other elements are separated by level as well.  We can view only the insulation, or fireproofing, or only the fireproofing above elevation 200', or only the cooling water piping, or only the cooling water return piping, or any combination of processes or elevations.  BTW, in this particular image all the electrical and instrumentation is turned off.