Re: [brlcad-devel] status of STEP Class Library in BRL-CAD

[Christopher S. M. <br...@ma...>]

Hi Mark,

On Jul 6, 2011, at 17:18, Mark <mp...@gm...> wrote:

> I worked with SCL a few years ago, and there has been renewed  
> interest in it from various parties. As a result, I copied my  
> version of the source from google code to github( https://github.com/mpictor/StepClassLibrary 
>  ).  Today I was searching for more users of scl, and found out that  
> BRL-CAD uses it - a fact that I had not been aware of, in spite of  
> adding information to the wiki page http://brlcad.org/w/index.php?title=STEP 
>  ! (When I added the info I thought, mistakenly, that I was the only  
> one working with SCL.)

We not only use it, but per prior talks with some of the original NIST  
developers, we had taken over maintainership of SCL.  Given our need  
for robust import/export of AP202 & AP214 geometry and lack of  
activity elsewhere, it was a natural fit.  We just hadn't gotten  
around to publishing an updated standalone SCL release outside our repo.

> * What license are the devs using for SCL?

We haven't changed the original SCL licensing terms.  Portions of the  
BRL-CAD repo are under different license terms.

>  http://brlcad.svn.sourceforge.net/viewvc/brlcad/brlcad/trunk/src/other/step/CMakeLists.txt?revision=43301&view=markup 
>  seems to imply that SCL is (C) US ARL, which does not make sense to  
> me.

If I recall correctly, the majority of the NIST-developed code is BSD  
or public domain.  Our additions, such as the build system file you  
reference is BSD just so it matches the rest of the build system.  We  
strictly interact only with OSI licenses that are unincumbering and  
readily incorporateable into derivative and collective works, or  
public domain code.  ;-)

> * Have you been able to use SCL with modern EXPRESS schemas?

I beleive so but that would have been work done several years ago.  We  
have already made quite a number of mods over the past few years since  
the takeover so best way to find out is to try one.  You have a  
particular AP in mind besides 11/203/214 files?

> * What are your future plans for SCL? Have you generated all the  
> code you will ever need, meaning that you won't ever have reason to  
> work on SCL again? Or do you intend to support more or newer STEP APs?

We're definitely not done.  ARL funded the development of an initial  
working STEP-to-BRL-CAD importer over a year ago.  More work on that  
importer is going on now and I'm hoping we'll get to an exporter  
sometime next year.

Cliff mentioned several of the SCL dev tasks currently on our radar.   
Code modernization, new build system, and portability to Windows being  
key efforts we need.  Restablishing a new project home is another as  
we get closer to pushing out an updated SCL release.

> If the latter, perhaps we can collaborate.

Collaboration sounds fantastic.  I view STEP as our preferred import/ 
export format for BRL-CAD given the breadth of entities it supports.   
It is the only open format I'm aware of capable of representing the  
majority of BRL-CAD entity types and operations.

Cheers!
Sean