Theoretically, in terms of its potential, 3D printing technologies can be perfectly used in the production of architectural mock-ups, successfully replacing traditional, manual methods of making them. In fact, this topic is very complex, and the key challenge for architects is the right way to design models and optimize them for 3D printing. Amongst the companies providing services based on additive technologies, the scenario often recurs when they receive files that are completely unsuitable for 3D printing, while person or company ordering printouts have neither knowledge of how to fix it, nor money to pay for it.

This article is a contribution to a very broad issue which is the proper design of architectural mockups in terms of additive technologies – it is not a tutorial or a list of good practices. Its task is to make architects (or their potential contractors) aware of the challenges they will have to face when thinking about using 3D printing in the production of mock-ups, what to pay special attention to and what mistakes to avoid? It was created on the basis of hundreds of conversations that I had with architects, architecture students and representatives of service and commercial companies who provided 3D printing mockups or sold 3D printers to architects. Here are the 7 most common errors we encounter during this type of talks…

1st mistake: architects “can’t do 3D printing”

It’s not really a mistake, it’s rather a problem… I’m not going to talk about the quality of teaching future architects at universities, because I simply don’t have the slightest idea about it. But I can say another thing: over the past seven years I have had the opportunity to talk to nearly a hundred people specializing in architecture in the context of 3D printing. None of them had a clue what 3D printing is, how the 3D printer works and what are the technological limitations of individual additive methods? Each conversation or meeting was a de facto short training in the basics of 3D printing, during which I made my interlocutors aware of what to look for when designing a mock-up, or what and why would it never come out on a 3D printer?

It can be said that the source of all problems in 3D printing in architecture is the state of knowledge of the architects who commission such prints. Lack of awareness of what additive technologies are and what their pros and cons are compared to other classic manufacturing techniques, results in a digital model that is unsuitable for printing or requires gigantic work to bring it to a level of feasibility. My other conclusion is that architects want to commission a 3D printout of a mock-up for not entirely rational and thoughtful reasons – they often do it because:

  • “3D printing is the future”
  • “others already do that”
  • “we wanted to try something different”
  • “I saw it on YouTube and it looked great”
  • “apparently it’s much cheaper …?”

2nd mistake: everything in one file

The classic situation: we get a 3D model of a multifloor building (let’s assume that a four-floor tenement house), which has everything: a perfectly mapped external facade, perfectly mapped each floor, perfectly mapped interior furnishings (furniture, fittings, staircases etc.). And it is all enclosed in one .STL file.

Theoretically, this type of design can only be printed in powder technology (CJP, MJF or SLS), but only if the appropriate scale and the smallest details resulting from this are maintained (see points 4 and 5). In practice, it usually turns out that this is impossible – in turn much cheaper and more popular methods such as 3D printing from thermoplastics in a fishing line (FDM / FFF) or light-curing resins (SLA, DLP, LCD) are not suitable for this at all.

To be able to 3D print this type of mockup correctly, each floor would have to be exported as a separate file, as would each of the interior furnishings or external façades (e.g. gutters and window sills). The real question is what about the windows in the windows…? If they are in the design, then why 3D print the interior of the building, if nothing can be seen through it? If they are to be transparent – can they be obtained in separate files and do they really have to be made on 3D printers?

To sum up – when we receive one such comprehensive 3D file, in 99.99% of cases it means the end of conversations about 3D printing. From the technological side, it will be impossible to properly implement – from the design side, it will de facto mean creating the project from scratch.

3rd mistake: models are sets of surfaces

Another common case is sending models consisting of surfaces. Personally, I had the opportunity to participate in the following four or five conversations:

  • the basis of the order was a conceptual mock-up consisting of several dozen simple blocks mapping individual buildings, spaced on a slab of 2-6 square meters
  • most of the blocks successfully fit on a 20 x 20 cm 3D printer table, while the others could be divided and combined after printing
  • the material did not play a role (i.e. PLA simple 3D printing could be used)
  • model infill was “any”
  • the deadline was “for now”.

During the initial talks, it seemed difficult to find a more trivial order – the only problem that would seem to be solved was the rescaling of the machine park to a dozen or so 3D printers. Unfortunately, before we had the opportunity to go to its solution, when we received files for 3D printing, another appeared – the solids were not solids, but collections of surfaces, with single walls arranged in their shape. In addition, the surfaces had a virtual thickness, striving for -∞.

As in the second case, it meant the end of the order. As far as we could undertake the correct reproduction of solids by drawing them from scratch, the clients were either not willing to pay extra for it, or it turned out that there was no time for it.

The same problem also applies to more complex models, such as the tenement house described in item two. It happens that the model consists only of external walls, on which the entire facade is designed, while the body of the building is empty inside – or rather: it does not exist; was not designed by anyone.

3D printing is based on solids. Even if we want to print the walls of the building themselves, they cannot be surfaces, only solids of a certain thickness / width (e.g. 1 mm).

4th mistake: incorrect scale

We return to the model of the tenement house from the second point – the designer prepared it on such a scale that the body of the building could fit on a table of FDM / FFF 3D printers with an area of ​​20 x 20 cm. The problem is that as a result, the gutters have a diameter of 0.05 mm, while the 3D printer head from which plastic is extracted has a diameter of 0.4 mm – correct printing is impossible. We also completely ignore the fact that it is to be created vertically, while incomparably better effect could be achieved if it was printed “flat” and glued to the finished building (see point 6).

A common mistake is the even scaling of buildings “down” so that they fit on the 3D printer, forgetting that in addition to the mock-up body itself, the dimensions of individual components also decrease. As a result, they cannot be printed correctly.

How to solve this problem?

  • keep a reasonable scale and larger size of the mock-up
  • scale the scale of the mock-up, but keep the selected elements in a larger size (scale), only to be able to reproduce them on a 3D printout
  • 3D print the solid itself, and all small elements that would not come out on the 3D printer anyway in a different technology and match them to the finished mock-up (see point 7).

5th mistake: too much detail

Error derived from numbers 2 and 4 – the designer knowing what are the limitations of a given technology – in our case 3D printing, should know if and when the detail comes out correctly and when not? If the mock-up consists of floors that are closed by walls and a roof without being able to view the interior of the building, the last thing you need in the design is tables and chairs, fully equipped with toilet and kitchen equipment and door handles on the interior door. Aside from the fact that such details are unnecessary in themselves, it is impossible to print them on a small scale on 3D printers (unless separately, but see error # 2).

6th mistake: one model = one 3D print

The classic architectural mock-up consists of at least several hundred small details, assembled and glued together. In the case of additive technologies, architects go from extremes to extremes and recognize that a 3D printer should print the whole model, preparing one comprehensive file. This leads us to the above-mentioned problems, when it turns out that in order to properly make a mock-up, it is necessary to extract a number of elements and details from it, for which there is usually no time or budget.

Meanwhile, at the very beginning, it is enough to think carefully about the project and prepare it taking into account all technological conditions, so that the printing of the mock-up takes place quickly and cheaply, and the end result would be really at a high level.

7th mistake: if we use 3D printing – then it all is 3D printied, i.e. lack of other manufacturing techniques

The last problem is the general lack of awareness about what 3D printing is – where are its advantages and where it will not work? The 3D printer is a tool for relatively quickly making plastic parts, light-curing resins that imitate them, or metal powders. It is not perfect – it has as many weaknesses as a number of other devices and machines working in other technologies. If you want to print large, flat surfaces – e.g. walls, a FDM / FFF 3D printer will be perfect. If you want to print small and precise details – elements of facade finishing, windows, window sills, furniture or people – a 3D printer of the SLA / DLP / LCD type is great for this.

However, there are things that are best cut from styrodur, wood or paper, or formed manually from modeling materials or cast from resins.

Architects should not order or make mockups from a 3D printer – they should create them from all available tools, choosing the best and the cheapest ones.
Paweł Ślusarczyk
CEO of 3D Printing Center. Has over 15 years' experience in buisiness, gained in IT, advertising and polygraphy. Part of 3D printing industry since 2013.

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