This post is part 3 in my series on Layer Theory. If you’re just joining us, here are the links to the first two posts:

  1. Part 1: LEGO and Layers
  2. Part 2: Do you need that Layer?

I highly recommend you read through all the comments in Part 2. There’s easily as much good advice and intriguing view points in the comments as there are in the original two posts. What follows in this and future posts is written in the context of all those amazing comments. In fact two forthcoming posts are directly inspired by the comments. This post however was mostly written before Part 2 was shared. As such it’ll be the least integrated into the comments from Part 2. That said, I expect all of you commenters to provide some awesome feedback below as well, as I’m sure you’ll have just as strong opinions on Layer Combinations.

Some of this may be self-evident, but—if I’ve learned anything in my discussions with other architects—your obvious is my blind spot and my apparent is your mysterious.

Layer Combinations: the Super Attribute

Fills are to Building Materials as Layers are to Layer Combinations, mostly.

When Building Materials arrived in ArchiCAD 17, there was a lot of discussion about them being a Super Attribute—an Attribute that contains and organizes other Attributes. Two good articles that talk about this concept are my post on Parameters and Attributes and Nathan Hildebrandt’s on Auditing ArchiCAD Models using Building Materials. Building Materials, used properly, revolutionized how many of us modeled and how many of us viewed our data. By viewing the models through the lens of Building Materials, we suddenly had so much more control over how various elements related to each other, and how they were displayed. With Building Materials, we could unify the display of 2D and 3D elements that represented the same stuff (because Building Materials could be used in Composites, Complex Profiles, various 3D Tools directly, and drawn using the Fill Tool as well). This one new Super Attribute, not only contained other Attributes and data (Fills, Surfaces, Thermal Data, priorities…), it could also be applied to so many elements, thus being a system on which an entire model revolved.

Before the Building Material Attribute, we had another Super Attribute: Layer Combinations. Layer Combinations contain a collection of Layers and are the interface between elements and Views (much like Building Materials are the interface between elements and other data). They are View focused Attributes, rather than Element focused. They are the primary hinge between 2D and 3D data and their display in various outputs (traditional 2D drawings, 3D model views, BIMx files, exported IFC files, etc.). As we’ve discussed (and will discuss more) there are a number of other ways to display data, but when it comes to Layer based filtering, Layer Combinations are what matters most. A well thought out, and manageable, Layer Combination system can make or break a file. If all your Views adhere to your Layer Combinations, the Layer and file management is simple. If you don’t follow your Layer Combinations, you are dealing with local rather than global data, and your file will become a heavy, unmanageable mess.

Layers and Layer Combination GraphSo what are your thoughts behind layer combinations?

Here’s my philosophy (I expect LOTS of comments).

  1. Try to look at Layers not from the element’s perspective but from the Layer Combination point of view: in other words, Layers are things that are collected within Layer Combinations rather than simply an Attribute of an element. Select an element’s Layer based on how you want that element to relate to the various Layer Combinations.
  2. Layer Combinations are a core management tool. Never use a custom (non-saved) Layer Combination for Layers in a saved View. ALWAYS use a saved Layer Combination. FOR EVERY drawing and View that will be in your Layout Book. Even one off views should have Layer Combinations. It’s about quality, not quantity. If you are always using Layer Combinations then you can review all your combos at once in the Layer Settings dialog. Each time you get lazy and don’t connect a View to a Layer Combination you are decentralizing your data management. Each time you are making more work for yourself.
  3. Try to have only one Layer combination for each type of drawing—one for plans, one for elevations, one for structural drawings, one for sections, one for site plans, etc. This is not just for simplicity’s sake, but also for clarity of output. If each elevation has a unique Layer Combination, it’s possible that the information will display conflict (certain elements showing up on elevation A and B, but not C or D). Every few projects I find there’s one elevation or plan that needs a particular Layer hidden or an extra Layer turned on. I really dislike these situations. It causes fragmentation, increased management and a higher risk of something else not showing up in the drawings.
  4. Layer Combinations are not just about documentation, but also about collaboration. Don’t forget the value of Layer Combinations for exporting data to consultants (whether that data is 2D, 3D, or something else).
  5. Find a balance between too few and too many combinations. As the number of Layer Combinations increases, the energy to maintain them increases at least as fast. If you add a new Layer, you have to manage it’s relationship to every Layer Combination. Just like the graph from the previous posts of too many vs too few Layers, there is a similar one for Layer Combinations. If you have too many Layer Combinations, managing them begins to take up too much time and energy (or just increases the probability that you’ll make a mistake). Yes, the amount of time is not great—minutes, not hours—but at some point the added value of more Layer Combinations goes to zero or negative.

Case Study

Practicing what I preach.

My base template has as few Layer Combinations as possibly. As a project evolves there are always a few more added. But I’ve found my ten default ones are the combinations I almost always need. The extras I add typically end up being unique to the project. So I find it valuable to just craft those as necessary. If you haven’t guessed, I really hate having unnecessary bloat in a file.

Simple Layer CombinationsMy default Layer Combinations cover the basics: various plan types, elevations, sections, interior elevations, 3D Model views, primary consultant drawings (that I typically model myself), and the all important All On Layer Combination. Before I talk more about the All On combination, I want to address a Layer Combination type you might have noticed is missing from my standard template: a unique Layer Combination for details. I have purposefully expunged Detail Layer Combinations from my template for a number of reasons, and those reasons overlap with my points above:

  1. Details and Sections, if both derived from the model, should have identical elements—if I’m going to model a thing, it should show up in the sections (and elevations). If I don’t want elements in sections and elevations, why am I modeling them? If the elements are so tiny that line weights obliterate them, then I either need to fix my line weights or not worry about it. The detail won’t show in the drawings, but when line weights are off, I’ll see it while I’m working. And some information in the model is in fact just for me and my team.
  2. A unique Layer Combination increases coordination and increases discontinuity. If there are elements visible only in the details, then those elements might get forgotten about or missed when working in other views.

In many ways my arguments against a details Layer Combination could also be made for not having distinct section, elevation, and 3D model Layer Combinations. Why not just one for all three? My view here is that each of those does have subtle differences. 3D model views probably contain entourage that is otherwise off in section and elevation (trees, furniture, people, etc.). Sections have more Layers dedicated to elements within and beneath walls and floors showing (or more importantly we don’t need to burden ArchiCAD with lots of hidden geometry turned on for exterior views). Of course all of this is subjective and tweaked to align with my workflows and project types (small teams or solo users doing projects under 10,000 sq ft.). Then again I’ll wager that these concepts hold for much bigger projects as well.

Why you need an All On Layer Combination

Finding Layers that aren’t in Layer Combinations

If you are working with others it’s almost impossible to avoid garbage Layers. Some Xref, imported element from another ArchiCAD file, or a lazy coworker is destined to add a Layer. Be vigilant, but accepting. It reminds me of LEGOs today. In my youth LEGO blocks were safe behind a patent wall. Competitors could sell similar sets, but not ones fully compatible with LEGO. As of late 2011, anyone could sell a set that had bricks almost identical to LEGO. Of course if you give me or any other lover of LEGO a blindfolded test, we can tell you every time which is a real LEGO and which is a cheap knock off (I’ve run unscientific tests at home with 100% success rates). Today no matter how I try to avoid it, my kids end up being given fake LEGO sets from some relative or friend who doesn’t know any better. These pieces, while an affront to my person belief system, end up mixed in the bins. I can wish them away, but my kids don’t care. They are inevitable and I have to deal with that.

Layer Combination Bloat plus garbage reveal

I do my best to delete non-standard Layers, merging them into the proper Layer, but sometimes like those fake LEGO bricks they (need to or will) remain. Purity and perfection are an impossible goal. It’s a case by case basis as to what to do with the data. Fortunately Layer Combinations provide a great way to manage and be aware of garbage Layers when they show up, so that you can make the required informed decisions. If your template has an All On Layer Combination—that has all your standard Layers turned on—whem you switch to that combination you can see if there are any oddball Layers turned off—thus signifying a non-standard Layer that either needs to be incorporated into your Layer Combinations, or preferably deleted and merged. This checking is made even easier by, after selecting the All On Layer Combination in the Layer Settings, sorting the Layers by showing visible first, then invisible Layers second (click on the eyeball at the top of the Layer list to accomplish this). Once you’ve resorted the Layers in this manner, all you need to do is scroll to the bottom of the list to see what garbage has appeared. In the example above, there is clearly a lot of cleanup required.

Drawing Manager and Sheet Index

Finding Views without Layer Combinations

I need to write a post or record a video on the Drawing Manager. Or probably both. It’s a great under utilized function within ArchiCAD. For now though I just want to mention that the Drawing Manager is a good way to check that all your views have defined Layer Combinations and are not “by custom”. To do this, open the Drawing Manager and turn on the list column for Layer Combination. If the drawing/view has an assigned Layer Combination it will be listed. If the drawing or view is “by custom”, the column will be blank. If that’s the case, fix it!

Section Looking East has no Layer Combination

A more interactive solution to finding Views without an assigned Layer Combination is to use the View Index, which is a default (and customizable) Index in any base template. Opening up the View Index will not only allow you to see similar data to the Drawing Manager, it’ll let you edit each View’s Layer Combination, Pen Set, Dimension Style, Model View Options, etc. directly. Like any Interactive Schedule, the View Index has a lot of different display and listing options. For whatever reason typically I use the Drawing Manager rather than the View Index—probably because the Drawing Manager can be easily left open as a palette and is a few less clicks to get to. But from a functionality standpoint, the Sheet Index is the way to go. I really need to force myself to shift over to the View Index (especially because it is placeable on a Layout). Whichever you prefer, both the Drawing Manager and the Sheet Index are great ways to keep an eye on your Views to make sure you aren’t using custom Layer Combinations.

Sheet Index with Custom

My philosophy above covers my guiding principles. Of course, see my rules of thumb from Part 2, especially number 3. I know I break at least one of my tenants in each of my projects. But when I do, it’s done with deep consideration and the utmost care. Furthermore when you consider different layer system methodologies, many of the rules above get turned upside down. But we’ll tackle that in the next post.

Bonus Tip:

How to Update a Layer Combination based on visible Layers from Link Ellis

First Question to Comment On:

How does everyone feel about scale specific Layer Combinations? I personally never use them. In fact I avoid all scale specific Attributes (no scale specific Pen Sets or Layers for me). What about all of you?

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  1. Jason Smith

    Hi Jared

    Your philosophy on Layer Combos – I agree with all you items.
    I do break item 2 sometimes. There is the odd custom view set that turns up, most are for details. If I don’t have the time to model the connection fully then I will copy a standard 2D detail (copy onto Archicad layer and turn all other layers off) to make the detail correct. Details from the floor plan view don’t always give enough detail in the detail window, particularly windows and doors. I will turn off the wall layer and 2D the the rest.

    My Template has a Layer Combo for each drawing view type and different 3D model types (full model, model without furniture trees etc, structure only, structure with MEP). The 3D views form part of the drawing set and I will also add 3D model views that are cut like the sections. Some Layer Combos also make some of the modelling easier by removing elements that get in the way. The template is used for all projects, some combos may not be used for some projects. There is also a Combo for Sketch plans, there is a couple of layers that only have info that will only be shown for the sketch plan. I have sections and elevations that are only for Sketch plans (cut objects turn black etc).

    Layers for Scale Specific Combos – I don’t have layers or combos that relate to scale. But I do have pens sets and MVO for different scales. Graphisoft NZ supplies the pen sets, which we have adopted, 1 less thing to update in the template for the next release of AC.

    I have thought about saving Combos for specific views that relate to schedules. An example of this could be only Rafters & Joists on, Schedule lists framing types. Its a pain if the layers are turned off when you save a view of the schedule. Also you don’t want the whole model combo on when you just want to see the framing elements you have selected in the schedule and want to view them in the 3D window.

    How you model and what outputs you need or want are directly related to the number of layers and layer combinations. Add Model View options, 3D display options, Renovations filters, Load Bearing Core view, 3D document view options and the list of outputs could be almost be endless. On my latest project (House) I used a view of Load bearing walls – Core only, as a 3D document so I could show load bearing walls under the first floor floor framing plan. The two views were over laid on a layout. I used to draw in 2D lines for the load bearing wall before, so not BIM.

  2. Jared Banks

    Thanks for sharing your system!


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