Open source alternatives to AutoCAD

Open source computer-aided design software may have everything you actually need.
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Editor's note: This article was originally published in May 2016, and has been updated to include a few additional options.

CAD—computer-aided design or computer-aided drafting, depending on who you ask—is technology created to make it easier to create specifications for real-world objects. Whether the object you're building is a house, car, bridge, or spaceship, chances are it got its start in a CAD program of one type or another.

 

Among the best-known CAD programs is AutoDesk's AutoCAD, but there are many others, proprietary and open source, out there. So how do the open source alternatives to AutoCAD stack up? The answer depends on how you plan to use them.

 

Let's start by being honest and upfront about something: If you're looking for a drop-in replacement for your existing CAD program that will provide identical functionality and workflow without making any changes to your processes, you're going to be disappointed. But I would argue that the reason for your disappointment has nothing to do with the licensing of the product—drop-in replacements for complex programs with long-time users who have specific needs and expectations for their software are hard.

The trick for deciding whether a replacement piece of software, whether open or closed, is a good choice for you is to tease out exactly what your needs are. The situation is no different than discovering that the person who insists that they "need" Photoshop is just using it to draw a few geometric shapes and remove red-eye from photos; what they really need is a graphics editing tool that can replace those specific functions. Whether it has all of the bells and whistles of the original is irrelevant if those features sit paid for but unused.

My personal journey through open source CAD programs was no different. I worked with AutoCAD briefly in grad school, so when I wanted to play with drawing three-dimensional plans for something, it was pretty much all I knew. But that alone didn't make AutoCAD the best choice.

As I've strived to replace more and more software in my life with open source options, Blender turned out to be just as good for my 3D modeling needs, whether I was playing with models created for a 3D printer or looking at landscapes exported from other programs. And for the relatively simple task of planning out my home landscaping projects, Sweet Home 3D has been an excellent open source alternative.

If your needs are a little more specific and you really need a dedicated CAD program, here are great open source choices to consider:

SALOME

The SALOME platform is an application and framework suitable for industrial design and simulation. It's a side-project of the 3D powerhouse, OpenCascade, and has some serious industrial users. SALOME integrates a CAD and CAE modeling tool with industrial meshing algorithms and advanced 3D visualization. Its geometry editor can import STEP, BREP, IGES, STL, and XAO files, and its mesh editor can import UNIV, MED, GGNS, SAUV, and more. It has integrated Python support.

As with all other CAD applications on this list, it's open source, so if you have in-house developers creating plugins for it, there's no need to deal with a clunky API. You have direct access to the code base.

 

SALOME desktop client

BRL-CAD

BRL-CAD is a cross-platform CAD tool that dates back to 1979, although it would take 25 years for the source code to be released under an open source license. In fact, BRL-CAD is so old that it has been credited with being the oldest source code repository of an application currently in active development.

Originally developed by Mike Muuss at the Army Research Laboratory, BRL-CAD is been used for decades by the United States military for modeling weapon systems, but it also has been used for much more everyday design tasks, from academic to industrial design to health applications.

So what does more than 35 years of development bring you? BRL-CAD is made up of more than 400 different constituent tools and applications spread across more than a million lines of source code. Not all parts are under the same license, with licenses ranging from BSD to LGPL to simple public domain; the COPYING file within the project's source code on SourceForge has more details.

FreeCAD

FreeCAD is a parametric open source CAD program that was created to be able to design "real-life objects of any size," and although it's clear that many of the showcased examples created by users are smaller objects, there's no specific reason it couldn't be used for architectural applications as well. FreeCAD is written primarily in C++, and if you're a Python coder you'll want to take advantage of the ability to extend and automate FreeCAD using its Python interface.

FreeCAD can import and export from a variety of common formats for 3D objects, and its modular architecture makes it easy to extend the basic functionality with various plugins. The program has many built-in interface options, from a sketcher to renderer to even a robot simulation ability. Currently in beta, FreeCAD is being actively developed with regular releases, but the developers warn that it may not yet be suitable for production use.

FreeCAD's source code is hosted on GitHub and is made available as open source under an LGPL license.

LibreCAD

LibreCAD is another CAD program that is designed to work across Windows, Mac, and Linux alike. A fork of QCAD (mentioned below), LibreCAD has an interface that will look familiar to AutoCAD users, and by default it uses the AutoCAD DXF format for importing and saving, though it can use other formats as well. LibreCAD is 2D only, though, so it makes more sense if your intended use is a site plan or something similarly, err, flat.

LibreCAD is licensed under the GPL and you can find its complete source code on GitHub.


These aren't the only options. Other good choices that are worth your time to check out include:

  • OpenSCAD, which is billed as "the programmer's solid 3D CAD modeller," owing to the fact that it is not an interactive modeler, but one where modeling is done with a script file.
  • QCAD, which is cross-platform but limited to two-dimensional applications.
  • SolveSpace, which is a parametric two- and three-dimensional CAD program.
  • OpenJSCAD.org, which is an updated frontend for OpenJsCad. Both are JavaScript-based 2D and 3D modeling tools that run in the browser and are made available under the MIT license.

Since we can't include all of the options here, if you have a favorite, let us know in the comments below.

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Jason Baker
Former Red Hatter. Now a consultant and aspiring entrepreneur. Map nerd, maker, and enthusiastic installer of open source desktop and self-hosted software.

Contributors

24 Comments

I use a 20 year old copy of TurboCAD running under Wine. It's better than any of the GPD'd CAD software available. QCAD/LibreCAD are so user-hostile, that using them is something only a masochist would consider.

I think you nailed it. The beauty of Linux is Linux itself, and the apparent obsession many users have to also use only OSS on it, is limiting their use of their computer, and is a loyalty of open source, that seems far beyond the philosophy the Linus and the Linux kernel.

In reply to by AC (not verified)

While not open souce BricsCAD IS a drop in replacement for Autocad. It even uses most of Autocad's same commands. It is also about 1/2 to 1/3 the price. BricsCAd also has a large community using the product. As a 20 autocad user, it only took minutes for me to get up and running with BricsCAD.

I would hazard a guess that most readers of opensource.com come from the programming world and thus would be far more at home with OpenSCAD. You simply code objects -- after a little bit of a learning curve to remember the basic commands it becomes an incredibly powerful parametric design tool. In general, I have found that students who are not already familiar with some form of visual CAD program pick it up more quickly. That said, you can have your cake and eat it too - as FreeCAD has an OpenSCAD module.

What we really need to work on is getting open source CAD programs into schools - so students become familiar with them first rather than getting locked into expensive proprietary packages.

I've enjoyed using OpenJsCAD, which is similar to OpenSCAD, but instead of using a domain-specific language, it uses Javascript. Runs in the browser, rendering models with WebGL. I used this to design many models for 3d printing, including my wedding bands.

In reply to by Joshua Pearce

I am not a seasoned programmer, point in fact the most difficult things I've coded were done in, or intended for, HP 48 series engineering calculators, namely an HP48SX & an HP49G. & my academic background is not one deeply related to coding (Mechanical Engineering). Speaking of CAD software, and this is actually in general terms, it really helps to have attended school! Cause programmer or not, you're gonna get into programmer's turf every now and then, when solving several problems into CAD software. For instance, drafting gears (cogwheels) depends on so specific equations, that nobody even tries to “draw” them - actually that's what CAD is for -, but the way of inputting those equations differs a lot between platforms. More than once have I requested help from friends & colleagues who are devoted to coding, in order to solve things.

In reply to by Joshua Pearce

Try Draftsight. Only 2D but a quite good one. Free for student use only.

Basic version of Draftsight is free for anyone, and there is a Linux version. You have to register but they don't hassle. The CAD engine is from Graebert who produce ARES Commander, and the same is in CorelCAD.
I need to produce industry standard 2D CAD drawings and Draftsight is the only product I have found that will allow this on Linux. (Yep, 2D is certainly not obsolete - millions of us still have to produce 2D stuff.)
Otherwise, FreeCAD looks interesting, but is only at about version 0.16 so it has a way to go. There are already autocad dwg import functions, Hopefully someone will do some AutoCAD command aliases for FreeCAD. Who knows - maybe I'll end up doing them :-)

In reply to by maurog (not verified)

Fact is none of these tools solve even close to the same thing as the commercial CAD tools do. BRL is the closest, but its modeling last time i use was just appalling. The others (why even include 2d?) just don't come close to tools like solid works, iron cad Autodesk and a bunch of other lesser known programs.

Realistically CAD in OS is so poor only a non engineer would use it.

KediCAD is the best that you sould try it at least.

I'd agree that there really isn't a direct replacement to AutoCAD. The other issue is that for quick and 'dirty' creation, things like TinkerCAD can help you put a concept model together quite fast without installing a program. But since both of them aren't open source, they don't need comment time.

I've used QCad community edition (forked to LibreCAD) to make a 1:1 pattern of something I was cutting out. I've also used Blender to make a model of parts of a standing desk. I then used LibreOffice to sort out all the pieces and place them so I could make the desk out of a single 1/2" sheet of 4'x8' plywood.

Salome-Meca is on my to-learn list, which I believe is open source and included in CAELinux.

Unfortunately I see too many situations where users try to use these OpenSource Apps as an alternative to AutoCAD but rarely does it work out for them. Being in the education business, I've trained many individuals that tried using them but found themselves either limited with what they needed done or restricted with their clients that needed to view the CAD drawing.

Hi !
All though not Open Source i use VariCAD as my main CAD tool. It runs native under Linux, Licens fee around 600 Eur. full 3D modelling and generation of 2D from 3D or generating 3D from 2D, automatic generation of BOM and it uses so little system resurces that i can run it in a virtualbox virtual machine and still manage full 3D models of a house.

I find it interesting how many people make idiotic comments about proprietary software on an opensource web site.. DUH!!!

I've been an AutoCad user for over 25 years and have been using Revit since 2015. I use the Revit for design and the AutoCAD for technical architectural drawings. I have a huge library that I have built over the years therefore another Cad software program would have to blow my mind for me to consider switching.

Julia Longtin, the president of HacDC.org, (The Capital's Hackespace) is also the maintainer of ImplicitCAD, a through-the-browser 3D system whose scripting language is base on OpenSCAD. The source code is written in Haskell, and it promises to handle curves much better -- or so Julia says.

It's a bit rough around the edges but you can try it out at http://implicit.faikvm.com/ and/or improve it at http://kalli1.faikvm.com/ImplicitCAD/Stable or https://github.com/colah/ImplicitCAD.

NOTE: faikvm.com is Julia's box, running out of her home (I think) and is not always the most dependable thing out there.

(Disclaimer: I'm currently on the board at HacDC, as I was too slow stepping backwards when they asked for volunteers.)

SolveSpace is my favorite. It can do more than all the others, and is extremely fast, small and elegant.

FreeCAD is ~100MB, LibreCAD is 17MB, SolveCAD does the same in 3MB.
FreeCAD uses python for its kernel, so it's awfully slow, but gets a lot of contributions.

It is not accurate to say that FreeCAD uses Python at its *core* and therefore is slow. The core of the system is OpenCascade which is a C++ library of good pedigree and the UI is based on Coin, on other respected C++ library. Python is used for extending the UI and so far I've not found FreeCAD slow.

I am a student and obtained free version of AutoCAD but when i try to install it in linux mint through Wine it gave error. Please can someone guide me in this regard?

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