When I was given the opportunity to purchase and use a LulzBot Taz 6 my first reaction was, "awesome". Until I started doing research on 3D printing an actual Revit model, "not so awesome". With a deadline for printing a project approaching my feeling of excitement turned to anxiety.
I found out that you just can't "press print" on your every-day Revit model and expect it to 3D print.
I also found out that there is very little information regarding the processes required to actually 3D print your working Autodesk Revit building models... So, I will save you the trouble of searching and do my best to break down the quickest and most effective method I've found to printing ANY of your Revit models.... Step 1 is the key...
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| LulzBot Taz 6 : 3D Printer Used to Create this Post... |
Hardware Used:
- LulzBot Taz 6
- LulzBot PLA Filament
**Tip**: Not all filament is equal... Do some research on your printer and what filament works best with it...
Software Used:
Autodesk Revit 2017
STL Exporter Plug-In (Revit)
Cura 21.04 (LulzBot Profile)
Process Outline:
1. Create and in-place component and "mass" inside the Revit building model elements.
** This step is the most important step in your process... **
Using extrusions, sweeps, and voids if possible (touching or encroaching inside face of walls/windows) create an in-place component that follows the massing of your building. This component will help the 3D Printer software generate a "water-tight" model. In-place conceptual masses will also work for more complex geometry.
This component/mass is the key to successfully printing a Revit model. Revit uses individual elements that are all their own"water-tight masses". Therefore, when you simply import a typical Revit file into a 3D printing software, it will try to print each individual element (refer to Step 5 to see what I mean). This would require a ton of "support structure" and many elements will not print because of the reduced scale.
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| 3D Printing Software requires a "Water-tight" mass... Build one inside your models... |
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| Try to use simple extrusions, voids, blends, and sweeps. This makes it easier to join your solids and form a truly "water-tight" object. |
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| Alternate view of "mass" built within the total Revit model... |
2. Create Dedicated 3D Views with your in-place component/mass visible along with your Revit model elements (ie. doors, windows, walls, etc...):
Now that you have made a solid mass built inside your model, turn your native Revit elements back on and get your views ready for exporting. This is important because, even though they all wont print, lots of the exterior detail (built with Revit elements) will print adhered to the solid mass. Below is an example of the Revit elements and in-place mass all visible in a 3D view.
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| Image of view with internal "Mass" and Revit elements visible. Ready for an STL export... |
3. Export to STL
There is a simple and free exporter in the App Store. Simply press export, select your units (make sure you select the same units as your Revit file) and click save. For units, I will typicall choose "Use Internal : Feet". Now your model is ready to be imported into your 3D printer software as an STL.
**Tip** The STL exporter will export current visible settings in the view. Which means you can temporarily hide/isolate elements and export them if need be.
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| Notice "Use Internal : Feet" for the units... |
4. Open STL file in Cura and scale it.
Most 3D printing software will import STL files. We used Cura as our 3D printer software because it has a pre-built profile that works with our LulzBot Taz 6.
Simply import your STL file and scale it as required.
**Tip** We found the scale factor from Revit to be easy to figure out: When exporting in "Use Internal : Feet" via the STL exporter, scaling the object in Cura by 0.6 yields a model print scale of 1"=40'... Scale factor of 0.7 yields a model scale of 1"=30'... and so on...
5. Check print layers in Cura:
All models will look great when you first load them into Cura... Look how solid this one appears to be:
But then, when you turn on the "print layers" view in Cura you see this:
The blue lines above represent "temporary supports" and the red represent solid print layers. The model above is a typical Revit model WITHOUT the internal in-place mass. You can see the printer software is only recognizing certain elements and a hollow model... If you attempted to print this you would get a blob of plastic.
After adding in our in-place mass, this is what the layer view looks like in Cura.
Notice the consistent red lines? Those are solid exterior "wall" layers of your print. This model will print well. Additionally, using the slider on the right hand side of Cura (or "CNTRL+Down Arrow" in Cura) you can step through each print layer and get a sense for how the model will be printed:
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In the image above (being sliced on the 18th level of this print), notice the model on the left is showing consistent red outlines and yellow fills. Meanwhile, the model on the right is full of blue temporary supports and inconsistent red outlines. The model on the left contains our "in-place" component and the exterior Revit elements.
6. Send to Printer via USB or SD Card
Now, the easy part... Press Print!
7. Print until its correct…. Or it prints all the way through…
I added this final step because, unfortunately, 3D printers don't appear to be the most consistent machines in the world. Perhaps, the more money you spend on a printer the more consistent it is. Either way, be aware (and don't get discouraged) if you have to print something a few times to get it right.
You can do everything perfectly and the print may fail for many different reasons... Sometimes layers shift, top layers show ripples, etc... I didn't want this post to be about the actual printer troubleshooting (there will be plenty of information out there when you're troubleshooting your issues).
In Conclusion:
Ultimately, the key to 3D printing your Revit models (as they stand today) is to take a little time and create a solid "in-place" component to fill in your prints. At the end of the day, we found this to be the quickest way to convert a model used for construction documents into a 3D printable mass.
Has anyone else found any other processes they've used?! If so, comment below...
I'll end with some awesome model photos:
Logging you in...
Clay · 405 weeks ago
TheRevitKid 72p · 405 weeks ago
Dave Edwards · 405 weeks ago
TheRevitKid 72p · 405 weeks ago
Mike Engel · 405 weeks ago
1) Swapped assemblies (roofs / walls / floors) for generic and thickened such that when scaled to print it would be of adequate thickness.
2) Thin elements were sent to a laser cutter and then inserted (windows)
3) Site model was sent to a CNC cutter.
End of the day, since the three were all extracted from a single Revit Model, the elements simple slid togerther like a puzzle.
TheRevitKid 72p · 405 weeks ago
davidrbeach 15p · 405 weeks ago
https://academy.autodesk.com/curriculum/bim-fabri...
It covers a few things (printable families, interiors, windows, CNC sites). We just added a couple of Lulzbots machines at our university, and love them...you made a great choice. They are rock solid and handle the hours (days) of printing per week that our students throw at them without a glitch. I would also recommend the nGen filament. It is super smooth in its printing, no heat creep issues and no clogging issues that we have had with PLA - I would rather it not print quite as glossy, but it is just super consistent which trumps all when working with a couple hundred architecture students.
TheRevitKid 72p · 405 weeks ago
Tom Cannon · 405 weeks ago
TheRevitKid 72p · 405 weeks ago
Dwane · 405 weeks ago
Adrian Esdaile · 405 weeks ago
1. Know your Printer.
If you are using an FDM machine, then yep, you need to model as masses - because your print will be layer-by-layer and need internal / external support for overhangs. Gravity sucks.
If you are using an SDM machine, like a Projet - go nuts! But follow step 2 below, and cleaning up powder is your problem :-D but you will get fantastic results!
2. THE RULE to follow - Minimum Print Size. Know what the minimum stable object dimensions are for your output print. If SDM, this could be 1x1mm, but for FDM you're looking at 1 layer by 2 x nozzle size. So that might be 0.2mm x 0.8mm for a 'standard' RepRap/Makerbot based machine. Note I said 'stable' as 0.2x0.8mm will blow away in a strong breeze (or cooling fan....) so maybe double that to 0.4mm vertically by 1.5mm horizontally. THIS IS NOW YOUR MINIMUM OBJECT SIZE AT SCALE. So if you are working at 1:1000, the smallest object you can print is 400mm high by 1,500mm wide. Yes, 1.5 METRES! Remember this will be 1.5mm wide when you print. this is a rule of thumb - you can print smaller, depending on filament, your printer, attachment to substrate (for details), phase of moon (important in 3D printing) etc.
Make sure any elements in Revit follow those minimum dimensions, yes, even wall / slab thicknesses. Set walls to Outside Alignment first (of course you've been making sure of that, right?) so they offset to inside. Modifications will be required to doors, windows, etc. if you want to show interior, print in two parts (or more) roof and everything else, or site / walls / roof. Remember you don't have to print right way up, print at whatever angle suits the print best.
3. Tidy that STL. How? Use Windows 10 (yes.....) and the built-in, FREE and EXCELLENT 3D Builder app. No, really. It's great. Select your whole STL, ungroup it, select all the parts, and pick Edit -> Merge. this will do THE BEST job of a Boolean merge you will ever find. This gives you a 'watertight' manifold object that will print nicely. it can also break model into parts.
4. For nicer removable 'tree' support use Autodesk Meshmixer - it does a good job, or Flashforge Flashprint that also does a nice job of tree support.
5. Load that STL into your favourite Slicer (I use Simplify3D) and make sure you print auto-support in your hollow spaces.
6. If your slicer doesn't give you a path preview, you're using the wrong slicer! get one that shows path preview as you can usually spot any glaring errors there before you make a 'spaghetti monster'
Cesar Trevizo · 403 weeks ago
Printer Kartu · 403 weeks ago
Lee Elder · 402 weeks ago
TheRevitKid 72p · 402 weeks ago
Mike · 390 weeks ago
Baptize · 388 weeks ago
When you say build a mass inside your model, would that be one mass for walls and roof? or two separate masses, one for walls and one for roof?
I'm also confused whether to you model in place or masses!
I tried encapsulating the model in one big solid box then use void form to shape the box but it did not work.
Please give me an idea on what to do. See this link for the model. https://1drv.ms/i/s!Avs44aXT6IfpnWGiPgcx0CrDJmKh
Chris · 376 weeks ago
jyoticoretech 1p · 373 weeks ago
Mark Ackerley · 367 weeks ago
Thanks for the post, just a bit of follow up using Dynamo...
https://forum.dynamobim.com/t/3d-print-from-revit...
Cheers,
Mark
Matt · 361 weeks ago