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.
Comments?
Mark Arvidson wrote:
The reason why I joined list is that I found the CAD files of the
Neo1973 at the openmoko.com <http://openmoko.com> 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 http://www.opencascade.org/ 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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