[PythonCAD] An open file format for Computer Aided Design (CAD)
Eric Wilhelm
ewilhelm at sbcglobal.net
Sun May 30 13:34:57 EDT 2004
# The following was supposedly scribed by
# Nikola Radovanovic
# on Sunday 30 May 2004 09:34 am:
>http://bugbear.blackfish.org.uk/~bruno/draft/
>
>I think it could be interesting.
Well, here's this old saw again:) I've been following and prodding the same
sort of issue for well over a year now. Art has yet to rewrite pythoncad
accordingly:)
Previous discussions have occurred on the cad-linux and cad-linux-dev mailing
lists, with some deeper, more technical exploration on the #cadfs channel at
on irc.freenode.net. We are now currently working at hypnotizing the
blendercoders into making this happen in blender.
I've also tried to work as much as possible into my perl modules CAD::Drawing
and such, using them as a test-bed for the textual-file ideas and also to try
to integrate existing file formats. This is not easy.
So, why isn't it going anywhere? For one, it has no corporate backing. For
two, I think it is going somewhere, but you have to realize the complexity
involved in making just one good tool that works with this file-on-disk
entity model. Furthermore, whichever tool does it first will be stranded on
its own island (per the autodesk plan) until it is able to read/write
industry-standard data via import and export.
But, this island issue is no stranger to anyone who has set-out to create
their own cad tool. Essentially, the easiest way to save your in-memory data
to disk is to dump it. That's all dwg is, and the only reason that it has
become de-facto is that it was here first (and marketing money never hurt
such a scheme.)
My current line of thought is that the files-on-disk model has the best chance
of takeoff as a repository where all different kinds of data are
imported/exported by a model/drawing manager. Thus, you have dwg, vrml,
step, iges, pythoncad, etc all going in and out of the same place. This
makes the manager program capable of storing the union of all features which
are available in all of these formats, and eventually someone will catch-on
and rewrite their app to connect directly to the manager.
--Eric
--
"It works better if you plug it in!"
--Sattinger's Law
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