by Jean Thilmany, Contributing Editor
Free, open-source 3D CAD systems are finding their place.
Until fairly recently, designers looking for open-source CAD software had several good two-dimensional programs to choose from but had a much tougher time finding 3D programs. There just weren’t that many out there.
That’s changing as 3D printing continues to grow in popularity, says Yorik van Havre, co-owner of the architectural studio Uncreated.net of São Paulo, Brazil. For architectural design he uses the 13-year-old open-source 3D system FreeCAD. In fact, he likes it so much he’s long helped with its development, a perk of using an open-source system, he says.
While frustrating, the dearth of open-source 3D systems is understandable, he says.
Creating open-source CAD systems is difficult because CAD software is complex in a way that few other applications are. To build a commercial quality CAD system, you’re looking at a lot of work, by a lot of experienced (and expensive) software developers. (See the article, Open Source CAD No, Free CAD yes, on 3dcadworld.com blog in July of 2012.)
That assessment, of course, is now four years old. While van Havre agreed with it at the time, much has changed, he says.
“The 3D front had been languishing because free, open-source CAD software represents a huge work, with very little interest outside a small sphere of architects, engineers and a few other types of designers,” he says.
“But now, with 3D printing, suddenly everybody needs a 3D CAD tool,” he adds. “This has lead to the birth of many new open-source 3D CAD applications.”
Designers call upon 3D printing systems to create the forms and shapes to be printed, says Terry Wohlers, president of Wohlers Associates, a 3D printing consultancy.
But many of those designers have come to 3D printing through the burgeoning maker environment. They don’t have an engineering or architectural background and haven’t used CAD software in the past and they’re not interested in buying an expensive CAD system, learning its many bells and whistles, and continually updating their licenses. They simply want to use the system to create the shapes they envision; the shapes they seek to print, van Havre says.
But he has one more reason for his interest in free, open-source CAD systems. Open-source software is frequently used by engineers in impoverished areas, or engineers who own small businesses or who work for small clients, he says.
“For small, starting-out offices, especially those in southern countries, the huge price of software licenses is a big factor,” he says. “You have to impose high prices for your services. You end up working for a very small segment of the population.
“In the field of 3D CAD, where professional software is usually very expensive, I see open-source solutions as a way for new professionals and small businesses to flourish without entering an enslaving relationship based on money,” he adds.
Open-source software doesn’t require an upgrade every year, doesn’t force you to buy new machines all the time, and is by definition accessible to anybody, together with its code, its documentation, its discussion forums, and its learning materials, van Havre says.
For these type of business owners, “open source can be liberating, if not revolutionary,” he adds.
More open-source CAD
Examples of newer open-source tools include Antimony, created by Matt Keeter, an engineer at FormLabs, which sells 3D printers and materials, and also a researcher at the Massachusetts Institute of Technology’s Center for Bits and Atoms.
Antimony users create designs by performing operations on common geometrical shapes. To create a cylinder, for example, a user would extrude a cylinder from a circle. The program relies on graphical based text, is fairly straightforward, and is available for Mac and Linux systems, van Havre says. It can also export files in the STL format for 3D printing.
As a researcher at the Center for Bits and Atoms, Keeter is developing AO, an open-source solid modeling tool. This program also uses text.
Older programs include Blender, initially released in 1995, which van Havre used for architectural design before turning to FreeCAD just under a decade ago. Blender is a 3D computer graphics program that does a good job creating animated films, visual effects, interactive 3D applications, and 3D models.
“But I felt Blender was aimed at another direction than what I needed, which was a more precise, technical application,” van Havre says.
Or, as Mike Szczys, managing editor of the website Hackaday put it on the site: “Using Blender to design a small object to send to a 3D printer is like using a bulldozer to build a sand castle. You can do it, but it’s overkill.”
Blender is best suited for graphics and animations and really shouldn’t be used for objects that aren’t mechanical, both van Havre and Szcyzys say.
With Blender leaving him frustrated, van Havre found his search for a new open-source program frustrating as well. Living in Brazil and working at a small company, he was specifically seeking open-source software.
“I had a little bit of experience in programming gained from working with Blender, but not enough to start something myself that had to have 3D display, rendering speed, and other kinds of high-level things,” he says. “That’s when I came across FreeCAD, which had all those features already. And it had a Python platform–like Blender–to build tools on. That was exactly what I needed.”
“At the time I bumped into FreeCAD around 2007, I was, like many other people, pretty frustrated with the lack of open-source tools available,” he adds.
In contrast to Blender, the general-purpose parametric modeler is specifically for use by mechanical engineers, product designers, and architects, says Jürgen Riegel, one of the program’s original authors. It imports and exports designs with standard formats that include STEP, IGES, OBJ, DXF, and STL, he adds.
It also includes a 2D component, which allows users to sketch 2D shapes or to extract design details from a 3D model to create a 2D production drawing. It’s compatible with Windows, Mac, and Linux systems, van Havre adds.
Now van Havre and his partner use the program mainly for what he calls the technical side of architectural design, rather than the creative side, which is often still reserved for tools like Blender.
“The first stages of design usually require you to test many undeveloped ideas, for which it is great to have a more free-form tool like Blender or even a simple pencil and a sheet of paper,” van Havre says.
“When ideas consolidate and your client has decided on one direction, you need to settle your design for it to become buildable. That’s where FreeCAD comes in,” he adds. “We import what we made with other applications or supports, and rework it to become sound and solid precise objects. We then extract plans, sections and views from the models, which will become the actual construction documents.”
Free time development
After van Havre had used FreeCAD at his architectural firm for a time, he became curious about those who regularly helped with its open-source development. The FreeCAD community of developers and users volunteer their time on development. The program itself also features a forum–as do many open-source software programs—where developers hang out.
For his part, van Havre—who joined the community in 2008 one year after discovering the program itself–says volunteering on the development side has been quite worthwhile.
Most of those who aren’t well acquainted with the term open-source view the fact open-source software is free with extreme suspicion, he says.
“But people who work on open-source software do it because they want to have and use that free tool,” van Havre says. “Almost all programmers of open-source applications are actually first users. There’s a creative, dynamic community around you. It’s fun. I’m not the only one who thinks development is worth more than money.”
The lack of marketing drive is also refreshing, he adds.
“Think about that for a second, an application where development direction is decided by the people who use it, rather than by marketing considerations,” he says. “We don’t need to sell you anything, we also don’t need to keep you hooked, or to force you to upgrade. You can use new files with an older version of the application, you can download and install the application anywhere, redistribute it to others.”
Some opens-source licenses–such as the one FreeCAD uses–even allow you to sell it. “Though why anyone would buy it is another question,” van Havre says.
Because most open-source application use open file formats too, what is contained in a file is always extractable, readable, and exportable. Often, the file user doesn’t even need to have access to the original application, he adds.
But he gets that not every designer will be swayed by open source.
“Just as not everybody wants to switch from Windows to Linux, I don’t believe everybody will want to switch to FreeCAD no matter how good it becomes,” he says.
Then he considers a second.
“But I can still hope,” he says with a grin.