Thou Shalt not do 2D. Thou Shalt not just do 3D.

In the BIM circles there is a lot of talk about Information. There is this belief that Information trumps 3D models; that it’s the I over the B or the M in the term Building Information Model. I think this is a misunderstanding of the situation. It assumes the Information is something outside of the three standard dimensions, that it has to be something like a text field in a schedule or data about facilities management, or perhaps flow rate through a pipe or some such esoterica. Talk like this can drive people into feelings of BIM Guilt.

BIM Guilt: the feeling that you aren’t ‘doing’ enough to claim BIM.

Talk of Information above all else can also be a handicap in learning ArchiCAD or another program. The BIMmountain is huge. And it can’t be conquered all at once. And in fact, focusing on the 3D model, or the drawings, or (shocker!) the design of the building, can be the route to both BIM excellence and mastery of ArchiCAD. If you don’t believe me that Social BIG BIM can emerge from a focus on modeling, read this post and watch the accompanying video, and then remember just how powerful the Morph Tool really is. But let’s step back even farther. What does Information even mean in the context of BIM? I have a working definition for you.

Information in a BIM: ANY discrete piece of code in a BIM file that furthers the production, coordination, design, or integration of the final building.

Now of course that is an insanely broad definition. And it needs to be qualified. All information is not created equal. Some has more utility than others. But deciding the relevance of the Information is the responsibility of the design team. It is the design team (architects, engineers, contractors, etc.) that needs to understand what should go into the file and what can be left out. What bits of Information don’t affect the four pillars of production, coordination, design, and integration. Or at least whichever of those aspects of BIM that the team is focusing on in the given project. So with that said, one can start to see that the 3D model is Information. That an intricate 3D model made of intelligent elements is very much BIM, even if it lacks claims to flashier “higher dimensional BIM”. Furthermore other 3D bits, whether metadata or digital approximations, are also Information that might be relevant. Especially if the BIM is being used for Design.

In other words to say the Information trumps the 3D model, that it’s the I over the B or the M, is wrong. Because everything is “Information” and if that data is used, then it’s elevating the value of an architect’s work. I’m now going to spend the rest of this post providing a practical example for all of us ArchiCAD users.

Model View Options – Show Minimal Space of Furnishing and Doors

ArchiCAD Model ViewMinimal Space for Furnishing and Doors is a function that we’ve had since I believe ArchiCAD 14. I would wager though that most of us don’t use it. I know I’ve only used it on a handful of projects over the past few years. I can use the personal excuse that this feature is more of a code issue for things outside of custom residential work, but that’s thin reasoning. Understanding the minimal space requirements for doors, furnishings, and equipment is important. And let’s just go out and say it. It’s a powerful design tool that should be integrated into YOUR TEMPLATE. Minimal space is invisible spacial data that should be used to inform design decisions. Imagine placing a door in any project and knowing whether or not there is the proper clearance. Or how about an oven or cabinet? ArchiCAD can do this. Most of us just aren’t using it.

What is Minimal Space? The Help Center will tell you.

ArchiCAD minimal spaceWhat type of elements have it? Furnishing and Doors; which should be interpreted as Doors, specific existing Objects and theoretically any Object you create, if you know how to add Minimal Space as a parameter. It’s too bad that Window Objects don’t have this function. It’d be really nice to see in elevation the minimal (maximum) space below windows for egress; the minimal space surrounding a door or window in elevation for safety glass or similar clearances which have a height component to them; or even the minimum space in plan for a sash of an inswing or outswing window.

Where and how can it seen? Currently Minimal Space is only viewable on the plan. Whether or not you see it is controlled by Model View Options. You’ll notice in my example image (and the settings of my MVO above), I’ve set the Minimal Space to show as a bright red. This red color is a unique pen in all my Pen Sets. It always shows red and is used to highlight warnings. (learn more about my Pen Set philosophy here). Whether viewing the plans with my gray scale pens or in full color, the red stands out; it is easy to see the minimal space and make any necessary decisions based on what I see. And since this information is usually not for printing, it’s easy to tell if it is accidentally left on in a View placed in a Layout.

minimal space gas stoveminimal space cabinet

Minimal Clearance in a KitchenIt’d be awesome if this info was also visible in 3D. Unfortunately it’s not (are you reading this developers!!!!). But, once you start thinking about minimal space as Information and criteria for design, then you can create it via other methods. To build most stairs, especially for residential or low rise projects, I use complex profiles. This is not as crazy as you might think. Here’s a video I did on why and how I do this. One of the most critical aspects of stair design, beyond keeping the treads and risers to code, is head clearance. There are few feelings worse in the architecture design world than realizing late in the game that your stair doesn’t work because of head clearance. Never a conversation you want to have with a boss or client. SO… here’s a trick I regularly use for stair head clearance verification. As part of the complex profile for the stair, I create a transparent fill above the stair representing the required clearance. I’ve been using this trick for years, but it works even better in ArchiCAD 17 now that the ends of composites and complex profiles read correctly (ie, based on individual Building Materials). This transparent volume can then be deleted once the design is solidified. When I delete this fill, I usually leave drafting lines in the Complex profile that represent the area. That way I can add back the fill whenever necessary to validate the design at a later point. (by the way, developers when you someday redo the stair tool, how about adding minimal space into the mix?)

build in clearance to your complex profiles

For anyone who’s intrigued by this idea, here’s another evolution to think about: You could create a whole layer for Invisible Spatial Data. On this layer you’d use various tools to create more transparent volumes to represent clearance requirements—turning radius for cars, travel clearances for wheelchairs, setback and easement information. This layer could be toggled on and off throughout the life of the project. And if you group these minimal space elements to the elements that they are providing additional data for, then the two will move in concert even if the layer is turned off (if Groups are enabled when you move the elements). If you explore this idea, create a Building Material called “Clearance Requirements” or something like that. Give it a nice red (or other obvious) warning color and a surface that has high transparency. Also set the Intersection Priority as strong as you can go. That way, whether the layer is visible or hidden, the elements representing the required clearance will cut into elements that are in their way. The resulting goofy graphics of an element in the wrong location will be a good reminder to fix the issue and preserve the necessary space. A caveat: Intelligent junctions aren’t automatic with Morphs. Morphs (and roofs and shells) have to be merged with the elements they will be affecting. Thus if you want to use this automated way of checking clearance you’ll want to typically use slabs, walls, columns, and/or beams to represent these volumes (and Complex Profile elements for weirder shapes).

in 3D and sectionThere is a lot of non-obvious (and non-visible) spatial data within a typical BIM that can and needs to be exploited. Minimal Space is but one of them. What other bits of spatial data do you include in your BIM? Or what other invisible data does this post get you thinking about? I’d love to hear your thoughts.


  1. Dave Olufs

    On the example of minimum space, when I see it as part of the parametric settings for doors, furniture, millwork, I skip over it. I can’t imagine designing a space without being cognizant of the spacial requirements, clearances, etc.

    The example of the head clearance on stairs is good. Car, truck and tractor trailer turning radii is another example where showing minimum clearances are good and necessary…

    By not using the minimum space parametric settings for doors, if I need to show code required clearances for push/pull sides of the door, I add dimensions on the plan. Without knowing, the minimum space parametric setting for doors may just show that piece of information if properly set and I’ll check to see if it does. But it just seems faster to layout the space and highlight spacial demands with dimensions.

  2. Jared Banks

    Dave, yeah doing it manually can definitely be faster in certain cases. BUT, if the information is saved as part of a Favorite (which is in turn part of your template), then it’s no extra effort to use. Once the effort is expended on the template. But this also raises another issue that’s worth a future post: automate what you need based on your team’s experience. Setting up minimum space might be more useful on larger teams and projects with younger staff, where less of this info is internalized. Hmm…seems like I should write another post about Template creation and user experience (both of ArchiCAD experience and general work experience).

    As far as vehicle paths, CADswift made an object: Though I feel like there might be a free object out there somewhere as well. Can’t remember where, maybe

    Thanks for the comments!

  3. Scott Graham

    I just finished a huge Senior Living Center that has lots of ANSI requirements. I knew of the minimum space features, but didn’t implement them at the time. In hindsight, it probably would’ve been worthwhile. Cadimage has a better approach to this:
    It allows you to program in the required clearances at the door PER APPROACH DIRECTION. This set of dimensions rarely changes between doors, so pre-programming them into a templat’s door objects is simple. All you do is select your intended approaches at each door when you place it and the appropriate fills show up.
    However, Cadimage is pricy, and there just isn’t enough of an incentive to buy and maintain 8 copies of D+W for this functionality.

    Since I need to rebuild our template from scratch for AC17, I’ll probably try to incorporate some of the clearances for doors, but GS should take a hint from Cadimage here.

    The minimum space routine also doesn’t yet allow as much flexibility as it should in placement and definition of minimum space either. I could live with having to enter door approaches in manually, but I currently cannot define a minimum space and place it/rotate it correctly in relation to an object. For example, a 48″ minimum width space in front of an appliance cannot be defined as such, instead I need to define it in relation to each edge’s offset from the appliance width. If for some reason the appliance gets wider, I need to adjust the minimum spaces accordingly. Being able to define the space only by it’s actual dimensions, and then move it in relation to an origin point on the object would be MUCH more versatile. Try defining an under-counter knee space with the current tool… More user control needs to be programmed into the GDL.

    The minimum space feature is has great possibility, but is still very much under-developed IMO.

  4. Jason Smith

    Hi Jared

    I have always seen the minimum space and always wondered how to get it to show. Thanks I’ll give it a go.
    Complex profile stairs I have always added hot spots to the stair profile so I can dimension the tread and risers where ever I like. You can also add hotspots for the handrail of head clearance heights. Sections are the best view to use the hotspots.

  5. Jared Banks

    Jason, YES! Great solution with the hotspots. And those are also visible when you select the element in 3D. Offers a lot of potential for leaving the clearance info in the final elements.

    Scott, I’ll have to check out the CADimage objects. I guess you could just save favorites with each approach type…which I imagine would be overly cumbersome. I never noticed about the other limitations of where the minimal space was taken from. Great points to keep track of.

    Thank you!


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