Friday, 14 August 2015

Affordable (Free!) 3D Modelling Software - A 5-Minute Review

When I started my adventures in the 3D printing world, I was using Alibre Design as my main 3D modelling software. While I still have a valid Alibre licence, they have been taken over by 3D Systems (as you will see straight away if you click on the Alibre link above), and the software has morphed into "Geomagic Design", which has different features and licensing terms, and it has been increasingly difficult to migrate my Alibre licences onto new computers, running new operating systems. I thought it was time to look for a new CAD modelling software system to generate designs to feed my 3D printer.

There are many, many free and low-cost 3D modelling software options available, so where to start? Well, a good place is to list my must-haves and nice-to-have features:


  • I am looking for something that will design "mechanical" components, rather than "free-form" modelling (i.e. a mechanical CAD system (MCAD), rather than an artistic "clay modeller")
  • Parametric modelling - e.g. the ability to edit a dimension and have the model "rebuild" itself (e.g. change the size and spacing of a group of bolt holes) 
  • True "solid modelling", not "surface modelling" capabilities - e.g. I need to be able to insert a hole or cut-away, and have the internal volume recognised as a solid rather than a void
  • Precision modelling capabilities - I need to be able to model to a fraction of a millimetre (even if my 3D printer's precision / tolerance are not quite up to the task sometimes!)
  • Familiar UI layout / functionality / workflow - I have used various MCAD software such as Alibre, Solidworks, etc for many years, and their UI and general functionality suits me, and I don't see any need to lean a completely new way of working to achieve the same goals; I realise I will need to learn new icons and menus etc, but I am looking for the same overall workflow concepts such as Create a Sketch / Extrude / Fillet / etc
  • Runs on Windows 10 (all of my home Windows machines have now been upgraded to Windows 10)
  • Exports models in STL format
  • 100% legal for personal / hobby use - I've been down the pirate software option, and I've used "extended trials" and "student licences" and so on, but I want to "keep it clean" from now on


  • Import / Export a variety of industry-standard CAD formats (e.g. IGES, STEP, etc)
  • Assembly Modelling (build assembles of multiple parts, to check fit and interference, etc)
  • Runs on other platforms (e.g. Chromebook, Android tablet, etc)
  • Will run without needing to "install" any software (I don't mind "installing" software on my own computers, but work policies prohibit the installation of software on the company's computers)
  • Legal for limited work-related use (I would sometimes like the ability to create simple models for finite element analysis )
Alibre Design still works very well for me, apart from the licensing / migration issues, so it's time for me to move on. SketchUp doesn't quite cut-it - it's a terrific package for what it does, but it falls short on the precision MCAD capabilities. After doing an exhaustive search (i.e. a few quick Googles), here's what I came up with for closer consideration:


Onshape advertises itself as "the first and only full-cloud 3D CAD system that lets everyone
on a design team simultaneously work together using a web browser, phone or tablet" - and it seems to be true. Forget what you might think about Cloud software, and how slow it surely must be - Onshape has a pretty full set of professional modelling tools, and runs really well in a browser on even modest hardware such as a Chromebook, and it has native apps for iPad and Android tablets.

Onshape running in Chrome browser on Windows PC

Native Onshape app on Android tablet 

Capabilities include a wide range of import / export formats, assembly modelling, and so on. It's missing a few high-end features, but it is still undergoing active development (automatic 2D drawing generation is coming soon, for example).

The software designers come from the team that developed SolidWorks, and it shows in the toolset and UI design - if you have previous experience with professional MCAD software, you will feel at home very quickly.

What is truly remarkable, is that all of this capability is available free for hobby / personal use:

You get access to ALL of the modelling tools for free - the only real limitation for the free account is the amount of Cloud storage space (5 GB for free accounts vs 100 GB for paid "Professional" accounts) - being a Cloud-based system, all of your models HAVE to reside on the Onshape cloud-store, but you can export models to your own file storage. 5 GB should be ample for all but the most ardent hobby modellers, though. In addition, you are limited to having 5 concurrent "Active" documents open at a time. For most hobby users, this won't be an issue - there is no limit on the total number of models you can have, but you may need to toggle some of them to be "Inactive" to free-up a new "Active" model. (Note that a "Document" can be a full assembly, with all of its parts, so you can have a lot of "Active" content at any one time!)

My only real reservation is that being proprietary software, there is always a chance that the owners might decide to abandon the free personal licence model at some future date, leaving me without free access to my models. However, their FAQ suggests that there is no intention for this to happen, so I'll give them the benefit of the doubt:

Q:  Will Onshape ever change or restrict the Free plan?
A:  Although we cannot guarantee that there will never be additional differences between the Free and Professional plans, we expect that CAD modeling, drawings, and data management capabilities will continue to be fully available under the Free plan.

All in all, if you are looking for a good 3D modelling capability, you HAVE to take a look at Onshape!


FreeCAD is a totally free, open-source 3D parametric modeller. It seems to be the best-developed open-source 3D MCAD modelling software I have come across, and it is still being actively developed and supported. As such, it has a large user community, and it is likely to be around for a long time to meet your needs. It is available on Windows, Linux and Mac, so will work for most PC users (but no Chromebook or mobile app as yet).

It's part-modelling capabilities arr pretty comprehensive (certainly adequate for my needs), and being open-source (with support for Python scripting), it has plug-ins / add-ons / extensions for a range of other software systems, such as Assemblies, 2D drawings, rendering, BIM / IFC, etc.

FreeCAD on Windows PC

In all honesty, I would have been perfectly happy with FreeCAD if it wasn't for the fact that it needs to be "installed" on Windows computers, which my work will not permit. I was looking for something that I could access occasionally at work, which is how I came across the cloud-based browser-accessible Onshape. However, if you're looking for 100% free, open-source 3D MCAD software, FreeCAD seems to be the pick of the bunch for now.

AutoDesk Fusion 360

The AutoDesk brand should need no introduction, but Fusion 360 might not be familiar to you. Basically, Fusion 360 is a professional-quality cloud-based 3D CAD/CAM tool, which supports both Mechanical and Free-form modelling. If you're familiar with Inventor, then you will understand Fusion 360. While it is a cloud-based service, it does require an application to be installed on your PC (Windows and Mac are supported) - it does NOT run in the browser, so other platforms (Linux, Chromebook, mobile, etc) are nor currently available options.

Fusion 360 UI on PC

The licensing model is rather unusual. AutoDesk has long offered free or very low-cost Student Licences, as long as you have a valid student ID, but these would expire after some period, and you would then be "strongly encouraged" to upgrade to a full licence. Fusion 360 is different:

As well as the traditional free 3-year Student licence, AutoDesk offers a free 1-year "start-up license" for "hobbyists, enthusiasts, makers, and emerging businesses that make less than US$100,000 in revenue per year". At the end of the 1-year term, you can reselect the start-up entitlement as often as you want (and as long as AutoDesk continues to support this licensing model). 

If you are familiar with AutoDesk products (especially Inventor), and especially if you want 100% compatibility with an AutoDesk work environment for example, then Fusion 360 is well worth a look. If you don't have a history with Inventor and other AutoDesk products, you might find it a bit more than you need, but then you only need to learn how to use those parts of its comprehensive tool-set that interest you. Going with an AutoDesk product has the advantage that there is a huge global Inventor user-base, and you can pick up any number of "How To" books from your local book-store (most of which should also apply to Fusion 360), so getting training and support is a no-brainer. 

And since it's free and legal (for now, anyway), why not give it a try if your interest is piqued?

And the winner is ......

Well, for now, it's almost a dead-heat. 

I really, really like Onshape - it works well, offers ALL of the features I'm interested in, and is truly multi-platform. My only qualifiers are the fact that it is Cloud-based (so won't work without an Internet connection) if that worries you, and the fact that it is proprietary software, and they might change their personal / hobbyist licensing terms one day. (I'll probably keep using it as long as it's free). In my view, Cloud-based software is probably the way of the future, and I have access to an Internet connection almost all of the time. The ability to view / refine models on any device at any time is a real plus (e.g. put the finishing touches on a design using your tablet while you're on the bus home after work). 

Otherwise, FreeCAD will also stay in my portfolio - partly because it's very good, and partly as a back-up in the event that Onshape is no longer available to me. It does MOST of what I want, but it isn't quite as polished, and it won't run on all of my devices (I can't install it on my work computer or my Chromebook, and I can't access it on my Android tablet, for example).

In third place for me is Fusion 360 - but mainly because it's a bit of a sledgehammer to crack a walnut as far as my needs are concerned - but if you have a track record with AutoDesk software generally (and Inventor in particular), you may well want to take a look.

For now, I'll give a Points Decision to Onshape - I'll post an update after a few months use to let you know if my feelings have changed.

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