Tag Archives: CadQuery

Why We Need Professional-Level Open Source CAD

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ad astra per civitatem – to the stars through community

At Mach 30, you’ll often hear us use this take on the famous Latin motto, ad astra, because we want to enable the broadest range of people possible to be part of the spaceflight community and  to contribute to our mission. A big, and sometimes insurmountable, barrier to entry for hardware project volunteers can be cost. If a user needs to pay tens or hundreds of thousands of dollars for engineering software licenses, you’ve just lost that volunteer. By utilizing open source tools, we ensure that everyone from the teenager with big dreams and a 3D printer to the retired aerospace engineer gets an equal chance to come alongside us.

Going hand-in-hand with open source software, is open standards and open data access. If Mach 30 can’t share things like CAD models, mathematical analyses, and research results with the broadest possible audience, we’re blunting the power of community. To see an illustration of this in action, see our recent blog post in which Mach 30 Reimagines The Martian with Open Source. By broadening access, we ensure that the weekend warrior working in her garage can reach us with her amazing ideas.

Up until recently, I had feared that Mach 30 was alone in thinking that the current set of open source CAD tools wouldn’t meet our needs. Then, I got an email announcing a new open source CAD discussion group organized by some members of MIT’s CSAIL lab.

Beyond just being impressed with the credentials of the attendees at the first video conference, I was struck by how dissatisfied the majority of them were with the current state of open source CAD as well. We certainly have a selection of open source CAD tools at our disposal (like CadQuery, FreeCAD, OpenSCAD, and BRL-CAD), which is great, but all of these tools seem to lack one or more fundamental components in the areas of stability, functionality, or UX (user experience).

If you don’t believe me, seat a CAD professional (on Solidworks, SolidEdge, Autodesk Inventor, etc.) in front of your choice of open source CAD tool. Even with training, you’ll see that they quickly become frustrated by the lack of what they consider basic functionality. I’ve gotten chuckles out of other CAD professionals before when I’ve mentioned my own efforts to use open source CAD for complex projects. Sure, there are individuals and small companies who use open source CAD, but I have yet to meet anyone who prefers the experience over a proprietary CAD package.

open source CAD

Modeling in CadQuery

When Mach 30 finds an area where the open source alternatives are lacking, we first look for a suitable existing project that we can contribute to. If we we’re unable to find anything, we’ll roll up our sleeves and build the tools ourselves. Currently, Mach 30 community members are direct contributors to the CadQuery CAD scripting framwork.

CadQuery has allowed us to do some very exciting things, such as driving the geometry for 3D models directly from the rocket science documented in our Mathematics Tool Kit (MTK). However, CadQuery is only part of the solution. We also need CAD and CAE (Computer-Aided Engineering) applications that are capable of things like assembly, interference detection, and analysis. Beyond just being capable, these applications need to empower the community member working with them to be productive so that their precious resource of time is used effectively and efficiently.

If we, as the broader Maker and Open Source Hardware communities, can hit the mark in the areas of affordability, data sharing, power, and usability with our open source engineering tools, we’ll increase participation and accelerate the already amazing pace with which open source software and hardware is changing the world.

So, what do you think? Are you happy with the state of Open Source CAD, depressed by it, or somewhere in-between? Are you able to make FreeCAD outperform SolidWorks or Autodesk Inventor? We’d love to hear from you about how you do it.

Yavin Thruster Sprint 1

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Mach 30 has started to use agile methodologies to manage its engineering projects, and the first of those to use an agile approach is the Yavin cold gas thruster. This last week, we completed our first sprint, and we’re all very pleased with the results.

For anyone that might not yet know about the project, it’s to develop a test stand connected to a source of pressurized gas, such as an air compressor, where different designs for the thruster can be tested. One of the aims for the project though is to develop and test new tools for future Mach 30 projects, such as CadQuery and our new Mathematics Tool Kit (MTK), a piece of software to make it easier to compile documentation around science and math proofs and analyses. We’re not only working to further develop these tools, but putting together a tool-chain for future design efforts. How this tool-chain works for Yavin is that we’re using MTK and a Python library to document and calculate aspects of the thruster such as wall thickness and nozzle shape. We can then create models with the same library in CadQuery, and export the model to be 3D printed.

In the first sprint, we took on 3 main items. The first of these was an export control review of the project, which can be found under the project’s Wiki on Open Design Engine. Second was a structural analysis of the gas chamber before the nozzle. The team generated a number of artifacts for this, including a document created with MTK detailing the analysis, a python library to support it, and an initial model created using CadQuery. You can see pictures of the model below, but the coolest part is that we printed it!

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This is just a proof of concept model though (it’s huge, and not an ideal size at all!). There’s a lot more work to be done! We have to produce another (or add to the existing) library to do the actual thruster design, and a number of other tasks.   Some work to do to make it so that CadQuery supports all the functionality we’ll need for making a good performing nozzle, but we also have a number of tasks ahead focused around testing.

For transparency, there’s one more item we had planned on doing, and that was performing a test calibration on a volunteer’s 3D printer.  Doing so helps us to build up information about how to calibrate other printers for printing future Yavin thruster nozzles. We don’t just intend for Mach 30 to print these, we intend for all sorts of people to do so, so we’re trying to make it as easy as possible on our end to print one of these.

We feel we accomplished a great deal for our first sprint, and we’re all very proud. If you care to hear more about our first sprint, you can check out our sprint review and retrospective here.

Mach 30 Update for March 2015

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This post was co-authored by Mach 30 volunteer Aaron Harper.

The Mach 30 Reports Hangouts experiments have continued in February and March.  Our new format is a round table discussion of current events in space, making, and open source hardware, with a focus on events happening at Mach 30.  This new format is paying off and the result is this month’s reports hangout is well worth the time required to watch.

This month, we have a report on Alicia Gibb’s book Building Open Source Hardware in which some Mach 30 members and projects are featured. We had some HUGE news in the form of contributions to open source design software and great strides on simplifying export control compliance for open hardware projects.  Check it out below.

For those that prefer a written update on the status of Mach 30 projects, you can still check out the March Reports page on Google Drive.  Many of these topics from this month will have periodic updates.  Naturally they will be covered in the new and improved monthly reports hangouts at Mach 30, so STAY TUNED!