Pentium/IPAS problems
06-Jun-94 01:29:44
Sb: #105437-Pentium/IPAS problems
Fm: parris ward 73767,3526
To: Tyler Colwell 74352,3010
Tyler,
Our company has done a bit of FE modeling in the past. In fact our company
president did an FE model of the human brain many years ago. But as you know,
that kind of modeling can complicated and tedious. We do not generally use it
for litigation for several reasons. Mainly because of the higher burden for
admissibility. Such an analysis is really a simulation, and not an animation.
Animations are used mostly as demonstrative evidence to illustrate an expert's
testimony. Simulations, on the other hand, can prove facts indepently. For
that reason they are much more difficult to get admitted into court. The
reliability of the computer code and the data are called into question. The
computer code itself sometimes must be submitted far in advance of trial for
the other side's expert to review. This can be a bit of a problem if the code
is proprietary. It must also be shown that the model can be validated. Then
there is the accuracy of the input data to consider. These issues by theselves
can lead to pretty extensive litigation. Basically your opening an expensive
can of worms. For that reason a lot of attorneys shy away from it. I've
personally heard of a case where an attorney got burned to the tune of $100,000
and had his simulation kicked out of court.
There are a lot of Recon people who use the EDC programs such as EDSMAC and
EDCRASH. We use them too. These are 2D accident reconstruction programs. They
have proven themselves over time in many jurisdictions and are now widely
accepted, so admissibility is not too difficult. However, even with these
programs, your input data is still open to scrutiny.
We do do quite a few simulations, but we use a widely known (in the Auto
Industry) and used mathematical modeling software package called MADYMO. It is
not a finite element model–rather you work with lump masses defined as either
ellipses or planes. You can assign surface elasticity values, joint
stiffnesses, object mass, center of gravity, velocity…etc. You can even
integrate FE models. The real beauty, though, is that every automobile
manufacturer uses it in designing their cars! Therefore, they cannot object to
its reliability and, thus, admissibility. Recently we even got it admitted,
without objection, in a federal criminal case.
We have have been looking at ways to link MADYMO and 3D Studio through
IPAS–thus making 3DS a sort of post processor. MADYMO looks a little rough
since it just shows you a bunch of animated colored ellipses. 3DS could dress
it up nicely for court use. But, on the other hand, I had one attorney that
preferred the "technical, computer look" of MADYMO because he thought the jury
might belive it more. So who knows.
Anyway, I don't know what to tell you about getting into FEA, other than it
could be a real battle. You might start simple, just testifying as an
engineer. Do some 3DS animations to illustrate your testimony. Then write
some custom IPAS routines which add the effects of gravity, friction, mass and
collision detection. Then you could sell your routines to the rest of us 3DS
users!
Hope this all helps
-Parris