Re: FEMM Vs. commercial code

["marsupiofr" <marsupio@xxxxxxxxxxx>]

Great post Keith !!!

I really agree on every points you mentionned. FEMM is also a 
good "starting" software if you want later to migrate to a big 
commercial platform. In FEMM, you (or you should) really know what 
you are doing. That's also true on big commercial platforms but you 
are often lost in so many options. With FEMM, you can learn the 
basics. The LUA extensions have also really boosted the software 
functionnalities. If you add the very clear user interface, the great 
documentation,... Honestly, that rocks !!!

--- In femm@xxxx, Keith Gregory <k.gregory@xxxx> wrote:
> Well ....
> 
> There are many differences between FEMM and typical commercial code 
but I 
> don't think that in the important area (i.e. kern - the solver ) 
there is 
> much difference. FEMM is as good as if not better than a lot of 
commercial 
> stuff. David has taken advantage of a very good mesh generator and 
produced 
> an excellent piece of software. That said it is not bullet proof 
and David 
> would be the first to admit that it does fall over occasionally in 
ways 
> that most commercial code would not. This to me is part of its 
attraction, 
> I use FEMM for teaching and it makes students think much more about 
what 
> they are doing than most commercial code would. It also has the 
significant 
> advantage for those who have little nor no spare money (i.e UK 
Academics!) 
> that it is free in a market that is occupied by software that can 
be 
> inordinately expensive. The first commercial finite-element code 
that I 
> ever used required a main-frame to run it and cost over £10,000 
(around 
> $30,000 in those days).
> 
> The problem that I have with a lot of commercial code is that it is 
> overblown, by which I mean that it covers up a lot of what it is 
doing in 
> the name of an easy user interface. FEMM does not do that although 
its user 
> interface is one of the most straightforward that I have ever come 
across - 
> only one commercial code that I know of comes close for ease of 
use. FEMM 
> does not have any of the almost CAD like drawing tools that 
commercial code 
> usually has. However, a little bit of ingenuity and old fashioned 
> draftsmanship usually allow a problem to be drawn directly in FEMM. 
I only 
> resorted to DXF import in the earlier versions of FEMM I feel no 
need to now.
> 
> FEMM does not have adaptive meshing you have to refine meshes by 
hand where 
> most commercial code does it automatically. I do not find this to 
be a 
> problem because most computers these days eat large problems so 
often I 
> just use fine meshes!
> 
> FEMM does not include other integrated solvers such as the 
electrostatic, 
> thermal or mechanical stuff that some commercial software includes.
> 
> FEMM requires you to set boundary conditions explicitly where (I 
think) 
> some commercial codes can do it (semi?) automatically.
> 
> FEMM circuit facilities are in their infancy for example they 
cannot 
> directly integrate external circuitry as many commercial codes can. 
(I am 
> of the opinion though that this may be possible using lua scripts).
> 
> FEMM cannot deal with dynamic (transient) situations as some 
commercial 
> codes can.
> 
> FEMMVIEW (the postprocessor) has most if not all of the tools that 
> commercial code has but requires you to understand what they do in 
order to 
> use them effectively. Many commercial codes attempt to determine 
things 
> like inductance at the push of a button, this has always worried me 
and I 
> find I don't trust the results. That said FEMMVIEW does not produce 
such 
> polished results as most commercial code and lacks some of the 
common 
> plotting facilities such as vector displays.
> 
> FEMMPLOT is useful but not something that you would use to produce 
> presentations. Most commercial code can produce camera ready stuff 
(all 
> show no substance?).
> 
> The addition of lua scripting has given FEMM very powerful 
facilities that 
> far exceed many commercial efforts. One of my undergraduate project 
> students is now using FEMM in conjunction with MatLab and lua 
scripts of 
> hundreds of lines of code to produce very effective interactive 
design tools.
> 
> I have found, over a few years of use now, that FEMM can do 
virtually 
> everything that I need to do as well as and sometimes better than 
the 
> commercial code that I have used in the past.
> 
> FEMM is a simple, straightforward but very powerful piece of 
software that 
> does exactly what it says on the tin! (apologies for a reference 
that may 
> only be understood in the UK). Finally, FEMM has one singular 
advantage 
> over all commercial software - it's written and maintained by 
someone who 
> is not anonymous, who will talk to you and listen to what you say. 
You 
> cannot put a price on that.
> 
> Keith.
> 
> 
> 
> 
> 
> At 21:43 12/11/2002 +0100, you wrote:
> >Which are main differences?
> >
> >
> >
> >
> >
> >
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