[freearchitecture] Open 3D CAD file format

[Eric Wilhelm]

# from Terry Hancock
# on Thursday 30 October 2008 11:14:

>There may be some other choices, but these two represent what I see as
>the main two strategic choices: either pick an industry-standard (but
>large, complex, and over-designed), or pick an under-capable but
> simple community-sourced 3D standard and work to extend its
> capabilities.

Hi Terry,

How does STEP deal with something like CSG?  From my reading, it seems 
to focus more on BREP.

With X3D, is there anything in this standard which significantly 
deviates from VRML?  If not, it seems that it wouldn't be expressive 
enough for any sort of mechanical or architectural CAD.

My plan with the VectorSection CAD hub is to initially implement all of 
the 2D primitives and 3D coordinate systems, along with some of the 3D 
mesh parts (and eventually solids if I can ever get a toehold on the 
ACIS format, and possibly brlcad's formats.)  This would allow 
converting meshes between e.g. .dwg/.dxf and .vrml, .x3d, .stl, as well 
as supporting the explicit drafted entities ala step AP201 (which, 
presumably includes placement of the 2D entities in 3D.)

The upshot of this in format terms (particularly with regard to avaCADo) 
will be a plaintext data structure which is capable of representing any 
non-associative 2D/3D CAD data.  The bonus is then that you don't have 
to write all of your own import/export routines.

Thanks,
Eric
-- 
  http://vectorsection.org/