OT: can someone help me with an open-source CAD program?

Mehmet Erol Sanliturk m.e.sanliturk at gmail.com
Mon Feb 16 20:29:02 PST 2015

On Mon, Feb 16, 2015 at 6:43 PM, Pierre Abbat <phma at leaf.dragonflybsd.org>

> On Monday, February 16, 2015 12:02:01 Mehmet Erol Sanliturk wrote:
> > It seems to me that your question is very broad .
> >
> > With respect to the following pages , if you specify more detailed needs
> ,
> > help may be formulated more easily :
> >
> > http://en.wikipedia.org/wiki/Category:CAD_file_formats
> > http://en.wikipedia.org/wiki/Comparison_of_CAD,_CAM_and_CAE_file_viewers
> > http://en.wikipedia.org/wiki/Category:Computer-aided_design_software
> The code is at https://github.com/phma/bezitopo .
> I'm pretty sure that no existing format will work as the native format for
> Bezitopo. The Bézier TIN surface and the alignment (sequence of
> combination of
> vertical and horizontal curves — what that is would take a while to
> explain)
> don't exist as CAD objects anywhere else AFAIK. The program will need to
> export and import DWG and/or DXF, but exporting and importing will not
> preserve the TIN structure or the spiral curves.
> If you're interested, let me know, and I'll set up a mailing list or we can
> talk off-list.
> Pierre
> --
> When a barnacle settles down, its brain disintegrates.
> Já não percebe nada, já não percebe nada.

My C++ knowledge is nearly zero ( I am using Pascal , I am studying C to
switch to C ) .
Therefore participating to programming is out of question .

My PhD thesis subject was the "a Multimedia Information Management System"
( 1996 ) .

My suggestion is to use XML for your data format . There is JSON ( you know
obviously ) , but I prefer XML .

Readability of XML is criticized . If you use consistently

<keyword ... ... >
</keyword >

left side will be belong to programs , right side will be belong to humans .

As a database of your measurements , you may use an XML database :


There are XML input / output libraries and existing XML databases .
Therefore , you do not need to write such modules . There are XML query
facilities .

If a Relational DBMS is used , you will need conversion of formats ,
reorganization of database schemas in BINARY .

In an XML database , these are not problems , because data will reside in
text form and , conversion , if necessary , will be trivial : Read XML into
a tree , write the tree as XML . Internal tree form is not so much
important .

It will be possible to use your XML database in any operating system , and
processor ( Small Endian , big Endian ) without any conversion because it
will not be binary

Output of DWG or DXF is not so much difficult , because you need an XML
reader to a memory tree , and a module to write that tree in DWG or DXF (
loss of some data is not your problem because of DWG or DXF formats ).

If any one needs data completely , he/she may use XML directly ( if
available in his/her program ) .

This will simplify your works considerably .

My opinion is that GPL license will prevent adoption of your software by
the commercial companies .
With respect to my readings , number of software projects adopting
copy-left licenses is declining .
I would prefer BSD or MIT if I select one .

If you want , you may ask any question off-list . I prefer your convenience
, and I wish to help as much as possible .

Thank you very much .

Mehmet Erol Sanliturk
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