The 3mf Consortium

.STL is a stagnant and archaic format for AM … only seems natural new standards should be adopted to help make things easier.

What do other people think?

What data not present in stl would be useful for printing on the Form1+?

I am not familiar with 3MF. However, the STL format does cause lots of problems for 3D printing.

Chris: In theory, an STL can indeed encode 100% of the information necessary to drive a good 3D print. In practice, STL is an overly flexible file format, and the result is that a lot of modeling and CAD software, taking advantage of this flexibility, generates STLs that are “broken” as far as the 3D printing process is concerned. If you Google for “STL repair 3D printing,” or a similar search string, you will find many pages that list (some of) the problems.

Scott, I’m making a note to look into 3MF. The decision about whether to add support for 3MF in PreForm will, of course, be based on factors like ease of implementation, demand for the format, and how widely adopted the format is. STL does have a big advantage to it, namely that nearly every 3D modeling/CAD software suite has the ability to export STLs.

(On a more personal note, I hate the STL file format more than anyone, because of the very real headaches that it causes.)

As always, thanks for the feedback!


Triangles are the simplest way to represent a surface. Object geometry constructed from triangles is the simplest way to represent a solid. STL is more than capable of doing this perfectly. More than “in theory”. STL is the “lowest common denominator” platform-independent data format available for the representation of 3D data sets (it even supports ASCII, making it “human” as well as machine readable).

Does that make it the most efficient or the highest-fidelity representation? No. But when you can buy a Terabyte of Disk Storage for $69, or a 3D Video card that’ll do a few gigaflops, who cares?

No, don’t malign STL. It isn’t STL that’s at fault for common geometry errors, but those CAD programs that are to blame. Non-manifold edges, extra unnecessary vertices and internal surfaces (“shells”), these are all artifacts of poorly implemented constructive solid geometry algorithms and have nothing whatsoever to do with the STL file format. These errors are as present in the CAD software’s native document as they would be in an exported STL, and would probably be present in 3MF, too.

Saying STL is to blame and so, needs to be replaced, is metaphorically equivalent to “shooting the messenger”. Blame the crappy CAD packages that generate busted geometry and not the format the busted geometry is using to get to your printer…

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I agree with Randy. I am a mechanical design engineer and I have been using Solid Works design software for at least 12 years and have exported my files in STL constantly into other CAD formats and other applications with no problems. I have never had to use any “STL repair software” because of the quality of the CAD software that I use. I have never had any problems with the STL’s when I print on the Formlab+. Randy is right about the CAD model having hidden artifacts left behind that really screw up the STL triangles. Yes…don’t kill the messenger!!

Read the specs and visit the site. It’s less about what .STL does ok, and more about what 3MF can do/offer.

Having additional, standardized info that can be passed around between different platforms, tools, etc is a good thing. Why pass around proprietary .form files, etc when one can pass around 3MFs? Also, given that the market is stagnant with cloned SLA hardware, would it not be wise to put an emphasis on innovation in software (among other things)?

Admittedly it may be a bit early, but it would be good to have this on a proverbial “radar” (aka a whiteboard).

Just my take.


The fact that STL is an “open” unregulated format is, IMO, its one of its strengths.

I use STL all the time as an interchange format without any problems at all except the problems introduced by whatever CAD software generated the geometry the STL represents. And the STL isn’t to blame, the errors are present in the CAD program’s native file format. So no, me personally, I don’t think we need a new format to fix anything that’s wrong with STL. There’s nothing to fix. The problems that exist are solely the product of bad CAD CSG, they’d still exist in any format of file, and that’s what needs to be fixed!

Now, if Printers were all somehow standardized, and there were “automat-like” fabs where you could go and get something made that you’d just downloaded, like a Kinkos copy center, then having a file format that was fully “encapsulated” to include both the geometry and any special fabrication-related elements/factors required for printing, then having a format like 3ML makes sense. To me.

I could see why the “big guys” in the printer/fab business would like this, but I’m a Luddite at heart. Change is bad. :grinning:

Your second part is more what it is about (I think) … and yes, more so for large industrial and engineering organizations in manufacturing. Plus OEMs of sw/hw that want to interchange easier. For us, whatever makes things easier and doesn’t break workflow. Time will tell. Some things that are old work perfectly fine. I didn’t mean to intentionally knock STL, only to ask for commentary on what 3MF can possibly contribute.

Question: Do any software packages out there besides PreForm consume or output .form files directly?


Unlikely. But a FORM file is specific to the Form printer. Another printer wouldn’t want to consume it. Slicing for 3D printing is generally very printer-specific. A 3ML, as I understand it, wouldn’t be direct-to-print, the printer that’s consuming the file still needs to convert it to whatever the machine’s particulars require… Like Java, it runs “native” on a wide variety of platforms and is highly transportable code, but it’s not actually “running” on all those machines, it’s running in an interpreter that’s converting the Java to machine-specific instructions.

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