CAD Software Blog


A More Perfect File Format for 3D Printing? 3MF Is Coming

by Cat McClintock

Did you know that, right now, there are 30+ different file formats for 3D--including STL, OBJ, VRML, WRL, PLY, and FBX? It’s like alphabet soup out there. Unfortunately, none of them is ideal for anybody who needs to print a 3D object.

failed 3D print

Not all 3D printed objects make the transition fromCAD design software to physical object successfully (Image:Failed 3D print, by 3DBenchy, via Flickr)

Take the most popular file format, STL. If you Google “problems with STL file,” more than a million results appear. Those problems can include

●     Surfaces contain holes and gaps (typically from a mesh that isn’t dense enough).

●     Objects don’t print as they are rendered on the screen.

●     Objects can’t be printed in multiple colors or materials.

●     Files are too big for the printer to accept.

As a result, designers often must take a number of additional steps to get a usable model to printer. But you shouldn’t need a Ph.D. in STL to produce the 3D objects you design. And that’s just one type of file. Multiply that by 30, and it’s easy to see why the 3D printing industry needs its own file format.

Freedom to Innovate with 3MF

Now, a group of industry leaders has formed to develop a file format that will specifically address the needs of 3D printing. This is especially timely as companies are asking more of their 3D CAD files than ever before.

Until recently, for example, most product developers limited their use of additive manufacturing to creating physical prototypes. But today, more and more are looking to the process to create production pieces that can’t be efficiently manufactured via traditional methods, like injection molding. 

3D printed object containing a lattice structure

Image: This lattice structure provides strength while minimizing weight, but is impossible to manufacture with injection molding.

As such, we can no longer expect designers to run back and forth between computer and printer, making adjustments until a good physical piece emerges. Today, we need the CAD model to clearly communicate (and the printing machinery to clearly understand) the properties of the model, so that it can be reproduced consistently every time.

The 3MF Consortium includes industry leaders like Microsoft, GE, HP, and PTC, who are working together to create a new full-fidelity file format. The 3MF Consortium aims to develop a format that is, in their words:

●        Complete: Containing all of the necessary model, material and property information in a single archive.

●        Human readable: Using common structures such as OPC, ZIP, and XML to ease development.

●        Simple: A short, clear specification, making development easy and validation fast.

●        Extensible: Leveraging XML namespaces allow for both public and private extensions while maintaining compatibility.

●        Unambiguous: Clear language and conformance tests ensure a file is always consistent from digital to physical.

●        Free: Access to and implementation of the 3MF specification is and will always be free of royalties, patents and licensing.

Imagine if you didn’t have to spend your time worrying about whether your file could be printed. What if someday anybody on any system could click Print and produce high-quality objects the first time? That day is getting closer, and using 3MF is how we’ll get there.

3D-printed feather

A successful print job. (Image: Colored 3D printed feather, by Creative Tools via Flickr)

PTC Joins the Conversation

You may already know that PTC has focused in recent years on streamlining the design process for 3D printing.

Now, as founding members of the 3MF Consortium, we will help ensure that the new file format meets customers’ needs no matter their 3D CAD system or printing system.

“PTC is committed to bringing visibility of manufacturing capabilities to the design engineer and streamlining the overall design-to-3D print process,” says Paul Sagar, PTC’s vice president, CAD product management. “This is a shared vision with the 3MF Consortium, and we look forward to collaborating with fellow industry leaders to make this a reality.”

3D Printing Starts with CAD

Are you using the right 3D CAD software for your current needs, or are you still using a legacy solution that used to do what you needed? For advice on how to choose the best CAD solution for your business, sign up for our three-day email course. We’ll help you compare your 3D CAD software options, give you some inside tips on pricing, and tell you what questions to ask. Sign up today so you’ll be ready for tomorrow.

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