Open source / Open Standard CAD development?

Michael Shiloh michael at
Fri Mar 7 18:45:01 CET 2008

I just returned from ETech, the emerging technology conference, and some 
of us discussed this problem. (In fact, the conversation started because 
of the Openmoko release of Freerunner CAD files.) All programming 
languages have a common source code form: ascii text. In contrast, there 
is no such standard for mechanical drawings or schematic drawings.

Similarly, there is no single standard for image data. There are a 
multitude: JPEG, TIFF, BMP, etc. but this is not as bad a problem 
because tools exist to convert from almost any format to any other format.

Since it's unlikely nor desirable that a single standard will emerge for 
mechanical or schematic capture, we came up with the idea of putting out 
a call to the open source community to develop tools to convert from 
from one format to another.

Some of this exists already, for example in Blender's ability to import 
from a number of different file formats. But we would like to see a 
project dedicated to creating a collection of tools to do this.


Mark Arvidson wrote:
>     The reason why I joined list is that I found the CAD files of the
>     Neo1973 at the <> site. It is great
>     that these files are
>     available, even if they are in a proprietary data format (the ProE, not
>     the STEP one), and very likely developed using a proprietary CAD
>     application.
> Developed with Pro/E if they are Pro/E files.
>     Personally, I have a software development company, in which I have
>     been developing tailored software for my clients, mostly with open
>     source technologies, and sometimes with, at least well known, closed
>     source techs like .NET . Therefore, it was a shockening moment when I
>     during 2007 did a consultancy project for an industrial company
>     producing water taps. It meant going back at least ten years in time,
>     back into proprietary hell! Proprietary systems (including proprietary
>     interfaces between systems) and proprietary data. CAD was done with
>     proprietary software, often with more than one CAD system, resulting in
>     incompatible, binary-only data.
> Having come from inside that industry, I have to agree.  A very big mess.
>     So my questions for the OpenMoko community are:
>     * Does there exist any "usable" open source CAD systems? (Is perhaps
>     Open CASCAE a viable semi-open option?)
> Open CASCADE may be an option for a kernel.  I do not know much about 
> it, except it has been used for numerical finite analysis more than 
> modeling.  It could probably do the work, but perhaps a bit slowly?
> CAD is a very complex subject.  There are many different solutions for 
> mechanical design, but only 3-4 for parametric controlled modeling 
> engines, and they are all high-dollar proprietary software packages with 
> extremely rigid licenses.  To date, I know of no OSS projects to try to 
> create a parametric modeling engine.  The original and on-going 
> development of the 3D parametric modeling engines (such as ACIS or 
> Parasolid) has taken many, many millions of dollars, so is a major OSS 
> undertaking, perhaps similar to the Linux kernel. 
> Blender has a sort of add-on parametric plugin, but it is quite 
> limited.  Alibre Design Xpress is free, but proprietary.
>     * Is it possible to use a human readable format for CAD data? (Is
>     perhaps STEP enough for development, or just a format for interchange
>     between different CAD applications?)
> STEP is a good, complete standard format that I believe all major 
> packages support well.  If I were going to create an OSS 3D modeler with 
> human readable format, STEP is a good way to go. 
> IGES is/can be a human readable format, but you lose the parametrics 
> with IGES.  The format was design to drive CNC machines, so is more 
> about the model exterior than anything else.  It's original design was 
> based on punch-cards, so is very heard to read by humans directly.
> There are xml formats, too, but none are really very standardized.
>     And the most important question:
>     * Is the OpenMoko community interested in  using open source tools
>     (possibly together with a human readable format) for developing
>     "non-software" parts?
> I think this product has primarily attracted software engineering 
> types.  We should get the word out to non-software people and increase 
> the audience for that question.
> --Mark Arvidson
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