REPLY Open Source Simulation Software (SD6816)

[SDMAIL Ames, Arlo]

Posted by  "Ames, Arlo" <alames at sandia.gov>

Maybe it's time for me to weigh in on this.

Before getting involved with dynamics, I worked in the CAD arena.  There, 
you have a strong need for data interchange (sending data from design 
organizations to manufacturing organizations), and some nagging pitfalls 
(the geometry you're interchanging is a result of a large set of nonlinear 
computations that people don't do in consistent ways in different platforms).

Standards for data interchange have been worked on almost since the inception 
of CAD itself.  IGES, PDES, and STEP are acronyms you can look up if you're 
interested.  Generally, the standards development process is long, arduous, 
and expensive.  The committees working on these things take forever to 
converge on a solution.  Vendors have a vested interest and want the standard 
to look like their system, and non-vendors often have difficulty in knowing 
the subtleties well enough to steer the solution in a direction that doesn't 
degrade the data as it's transferred.

Once a standard exists, vendors play a very cagey game implementing it.  
Implementation and maintenance cost money (money that customers aren't aware 
of and are reluctant to shell out), so vendors often write minimal 
implementations.  Implementation of the export portion of the specification 
risks losing customers, as they can now migrate to competing products more 
easily than by re-creating their models.  Implementation of the import portion 
of the specification can make it easier to steal customers from other vendors 
by the same logic.

Vendors thrive on adding specific features that other vendors lack -- such 
features distinguish their products from the pack, and are often the only 
basis for competition.  Adding vendor-specific constructs to the 
specification drives toward translation is difficult.  Vendors don't *want* 
to tell everybody the data structures for their new whiz-bang features, so 
they don't want to add them to the spec.  If you add general capabilities to 
add features without adding the specification (e.g. general attributes), 
vendors will use them in all kinds of creative ways to make loopback tests to 
work (so they can show that their translators are successful), while 
obfuscating the translation for any vendor.

When you implement inter-system translation, you are creating a new ecosystem, 
with predator and prey behaviors.

All of this isn't to say that translation isn't a good idea.  It's a great 
idea.  I have spent a lot of my career encouraging vendors to do just such 
things, and to export their data *in any form* so that we can get hold of it, 
because information is power, and even if you have to work hard to deal with 
it, it still is an enabler.  It's just complicated.

Note too, that once you start participating in this stuff, you're part of the 
ecosystem.

Arlo Ames
alames at sandia.gov
Posted by  "Ames, Arlo" <alames at sandia.gov>
posting date  Thu, 13 Mar 2008 14:58:20 -0600