CAD Program

[Troy A. Newman]

I went a class on Pro Engineer a few years ago. At the time company (PTC)
was touting that the 777 was designed exclusively with Pro E. Also that
General Motors used Pro E and its add-ins for vehicle design.

For those that don't know Pro E is a modeling program. Instead of  using
drawings the parts are modeled. Once they are modeled then you can export to
a drawing very simply and can look at any view or any scale. This is a very
powerful tool. It goes beyond 3D CAD. There are many things that you can do
with Pro-engineer and its ad-ins from Heat load calcs on electronic
components, to actual mechanical analysis in what they call Mechanica. You
can have the modeling program actually calculate the size and mass of a
counter balance needed on a crankshaft of a single cylinder model engine. I
know because we did that one in the class.

PTC the company that sells Pro-E also provides a free or used to provide a
free version that is much toned down....called Pro-Desktop Express. Its a
little more complicated to used but there are books out there that can help
you.

>From what I understand PTC doesn't really sell Pro-E its a leased program.
and it goes for about 500K a seat. This depends on what kinds of add ins you
need and also provides 24/7 Customer support. I understand that this is a
NASA type budget and we are not building spacecraft.

The free version is very versatile for our needs as modelers. I have been
using it for a couple years now. I still have AutoCAD 14 and fall back on it
if I want a simple drawing...ProE and Pro-Desktop requires you to actually
model the part. Its a bit more to play with a  sketch.

One thing that Pro-desktop does really well is give you an idea about wing
sections....You can create objects that have your airfoil cross sections at
both ends then just connect the dots to create a solid wing that will
actually be a model of your wing. You can then check its relative stiffness
and vary parameters like chord at the root of the airfoil and compare the
stiffness of the two versions. You can then create what they call a cut for
your ailerons or elevators and you can see how these change the stiffness of
the wing section. Its a very powerful tool and its free just need to learn a
little about making it work.

Another thing you can do is create a fuse and a wing..then determine where
you want the CG locations and with some parameters it will place the wing in
the right location for you. If you change a sweep angle or a taper ratio or
even span....the program can automatically move the wing to the proper
location based on your original criteria. Again as I said very very
powerful.

 You might look into it...If you are looking for something really good. Not
always the easiest path to your goal...but a very good product. And its Free
or used to be free not sure if it still is. I have been using it for a few
years now.

Troy Newman

----- Original Message ----- 
From: "Bill Glaze" <billglaze at triad.rr.com>
To: <discussion at nsrca.org>
Sent: Saturday, March 26, 2005 1:13 PM
Subject: Re: CAD Program


> Jerry:
> Many thanks for your reply.  I was disappointed about AutoCad in that it
> was great for topograph maps, and great for drafting, (after all, that's
> what it calls itself) yet wouldn't do this simple wire drawing
> requirement of mine.  I'm keeping your communication and will be looking
> into your link when I get a moment.  Actually, I'm pretty interested.
> It's common knowledge that the B-777 was designed without a single paper
> drawing, .(or so the legend goes; don't see how) but I doubt that Boeing
> was using a $3500 Cadd program, either.  I've heard of programs where
> the program developer had a software engineer set up a desk in the
> client's office for on-site help of the most immediate kind.  Wish I
> could afford to have someone do that for me!
>
> Bill Glaze
>
> Jerry Budd wrote:
>
> > Bill,
> >
> > I don't know first hand because I've never tried it but considering
> > who all is using it I can't imagine it wouldn't.  Ashlar has a much
> > higher end product called Cobalt that does all of what Graphite does
> > plus the high end solid modelling functions, but it's way more $$$
> > (nearly $4k).  On the other hand it compares favorably with ProE which
> > is ~$20k.
> >
> > All of the Ashlar products are available for a fully functional two
> > week trial via download here:
> >
> > http://www.ashlar.com/demo/index.shtml
> >
> > You might consider downloading Graphite, importing your old CAD file
> > from AutoCad and trying it.
> >
> > I think the important thing to consider is this.  There are a lot of
> > CAD programs available out there with a lot of capability that are
> > downright CHEAP (some are shareware/free).  Most of them are quite
> > difficult to use and require a significant learning curve to be able
> > to do anything of value at all.  I have found it better to pay a
> > little bit of $ to have a CAD tool that has almost no learning curve
> > at all as I frequently go months at a time without using the
> > software.  When I go back to use it after a layoff it only takes a few
> > minutes (I mean single digit here) to be back up and working. It's
> > that easy.
> >
> > I currently use an old version of Ashlar DrawingBoard on my Mac that I
> > bought 8 or 9 years ago (still runs fine on OS 10.3.8 under Classic).
> > I downloaded the trial version of Graphite for OS X last night and it
> > has the same intuitive interface.  The main reason I'm thinking of
> > upgrading is to pick up the ability to import/export a much greater
> > variety of file formats than what DrawingBoard handles. Being full OS
> > X native is a plus also.  BTW - FWIW, all of the Ashlar products are
> > offered for both Windoz and Mac.
> >
> > Thx, Jerry
> >
> >
> >> Jerry:
> >> Can you take intermediate cuts with it, and it will come up with an
> >> inference of the station?  that was my main complaint with Autocad
> >> Bill Glaze
> >>
> >> Jerry Budd wrote:
> >>
> >>> Ashlar Graphite, far and away the easiest CAD program out there
> >>> (important for CAD neophytes like me), it's a direct descendant of
> >>> Ashlar Vellum.  The learning curve with it is about a half hour
> >>> long. Once you use it you won't want to touch anything else.
> >>>
> >>> It's also fully capable, Scaled Composites used it to design
> >>> SpaceShipOne and White Knight.
> >>>
> >>> It is a little pricey but there are several upgrade discounts
> >>> available, depending on what software you currently own, where you
> >>> work, etc.
> >>>
> >>> http://www.ashlar.com/products/graphite.html
> >>>
> >
>
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