to all those brains out there-help!!! i don't have time or
money to waste on weak cad programs. i need a great cad program to
design a twin rotary amphibian. i am a newbie at cad. (no habits to
break) i will also be purchasing a dedicated laptop for the job.
suggestions on brand? thanks george g. on the vote for rhino. does
anyone else have experience they would like to share?

-- flyboy


I like Rhino.

Paul Lamar


A lot depends on what you want to do. In the CAD world there are many
flavors of programs, but they usually are categorized into either parametric
and non-parametric.

In very general terms, parametric programs allow the user to create designs
where some dimensions are related others such that one can change one
dimension and have related dimensions automatically change. For example,
one might create a shaft with a bushing around it. One could specify that
the clearance between the shaft and bushing must always be a specific value.
If you later elect to increase the size of the shaft, the bushing will
automatically increase in dimension so that the specified clearance is
maintained. This is just one (simplified) example of parametric behavior.

Non-parametric programs, do not respond as noted above. If one wishes to
increase the size of one part, the user is often required to manually redo
the other parts.

SolidWorks is one example of a popular parametric design program while Rhino
3D is an example of a non-parametric program. Each has its respective
strengths and tradeoffs.

In addition to this feature, some CAD programs permit designers to create
very smooth, very complex surfaces while others are more limited in this
capability. Arguably, Rhino 3D currently permits users to create much
"nicer" surfaces as opposed to SolidWorks. In this context, one simplistic
example of "nicer" refers to how smoothly one surface blends into other
surfaces. Imagine sighting down a car's body. "Nicer" surfaces will not
display kinks and obvious transitions while less nice ones may have
noticeable surface transitions. This surfacing capability is one of the
reasons Rhino 3D has grown so popular among industrial designers, and others
wishing to create smooth, nice looking shapes. But don't misunderstand;
SolidWorks creates nice surfaces, but Rhino 3D does it better...at least for
the moment.

If one accepts, for the sake of argument, that Rhino 3D has a more powerful
surfacing capability, as compared to SolidWorks, and one is more interested
in form design, it might be a better choice than SolidWorks. On the other
hand, if one is designing mechanical assemblies with a great number of
anticipated dimensional changes, SolidWorks might be the program to choose.
Of course there are other programs out there and other criteria to consider,
and there are certainly other features to consider, even between Rhino 3D
and SolidWorks. One should also not forget popular programs like AutoCAD.

More recently, McNeel (producers of Rhino 3D) have addressed this parmetric
issue by providing a well behaved path such that nice looking,
non-parametric shapes can be designed in Rhino 3D and then imported into
SolidWorks where the internal mechanical components of the user's design can
better be designed to fit into the Rhino 3D shape. Unfortunately, if the
user later elects to change the size or layout of his mechanical assembly,
such that it no longer fits inside the Rhino 3D shape, one has to go back
into Rhino 3D to resize the enclosing shape.

Now, if cost is not a major issue, one can always use Catia from Dassault
Systemes. It is parametric and has very powerful surfacing capabilities.
Catia is the standard for companies such as Lockheed and Boeing. But you
had better think it over. A single user commercial (retail) version of
Rhino 3D lists for $995. A single user commercial version of SolidWorks
lists for about $4,000. And Catia goes out the door for $10,000 to $14,000.


Then there is the issue of ease of use or the learning curve. Clearly, the
more features a program has, the steeper that curve may be for people new to
CAD design programs. Rhino 3D is alleged to have an easier learning curve
as compared, say, to SolidWorks. And some would argue that Catia is even
more difficult to learn.

I happened to use SolidWorks for a lot of my mechanical designs, but I am
also very familiar with Rhino 3D and often recommend it to those more
interested in esthetics. I know that Paul likes Rhino and feels that, up
until now, it has satisfied all his needs. But Rhino would not have
permitted me to design the things I have, such as gearboxes for turbine
engines and other mechanical assemblies.

So, where does this all lead. Personally, I would recommend SolidWorks
unless you are primarily interested in producing things with very complex
surfaces. Most amateur aircraft, however, do not involve such surfaces. I
know of one aircraft design being done by a close friend using SolidWorks
which is outstanding. I doubt that it could have been done in Rhino 3D.
There were many dimensional revisions which would have been exhausting to do
in Rhino.

I don't know much about AutoCAD, so I'm in no position to comment
intelligently about it. But I have used earlier versions of Catia and think
that, for most amateur designers, it is overkill.

I'm sure that Paul has other views and know he will be responding to this
message. If he doesn't I'd be quite surprised.

George Lazik
Woodland Hills / Santa Paul California

I designed this gear box in Rhino and had it made in the same NC shop
George had his made :) I will say one thing about Rhino Ver 3. It doesn't
do variable radius fillets worth a damn. version 5 is out so I don't
know if they fixed this.

Cowls in aircraft are very important because you must fit all the
parts inside. Rhino does cowls much better than Solid Works.
It is tricky to do cowls but I can help. It took me about
a month to learn how to do them. Not 24/7 just off and on
for a month.

IMHO it is not worth $4000 for Solid Works.

Paul Lamar




Hi Paul

I have SolidWorks and it's very good but the learning curve is steep.

If Flyboy only wants' to design an airplane what about Aerologic link
attached.

http://www.aerologic.com/index.html<http://www.aerologic.com/index.html

Might be worth a look?

Clive  England


Flyboy,

Paul and I are friends, but on this issue, we have differing opinions. He
firmly believes Rhino can do everything a newbie aircraft designer wishes.
I disagree. Rhino is outstanding if what you want to do is conceptual
design without many anticipated changes. But I think it is too limited in
those capabilities necessary to do an all up design. My vote goes for
SolidWorks if it hasn't been obvious up to this point.

You should note that in all these programs, there is also a hidden cost that
hasn't been discussed, and that is the time you spend learning to use these
programs. What often happens is that someone begins with a less powerful,
budget level program, only to quickly run up against its limitations. So
what they do next is upgrade to a more powerful (suitable) program, and much
of the time and effort they spent learning the first program must be spent
all over again learning the new program. True, there is usually a
noticeable "transfer of learning" because many of the concepts of using one
CAD program applies to others. But, still, you have to spend that time
learning the new program.

In other words, it is often better to begin with the appropriate program,
even if it costs more, than to start with a lightweight one and run into its
limitations.

Having said this, let me pass along a piece of information many are not
aware of. If you are a student or educator, virtually all of the companies
offering CAD software have extremely large (massive) discounts for their
products. For instance, the academic version of SolidWorks sells for about
$189.00 (as opposed to $4,000) and is a full featured version. In fact, it
also includes other full featured programs, such as those from COSMOS (FEA,
FlowWorks, etc.). A great deal. The only limitation is that the license
expires in about 12 to 14 months. But by that time, you will have had an
excellent opportunity to try it out and learn the program, and to decide if
you want to purchase the retail priced version. The academic copy of Rhino
3D is about the same price.

I even know of people who have gone down to their community college and
registered in a one hour class just to obtain a student ID which they then
use to purchase academic copies of all sorts of programs. They argue that
the savings instantly repay the token cost of registering in the class, even
if they don't bother attending it. I neither condemn nor condone this
behavior; I'm just mentioning it here.

Another thought. You should be able to download a trial copy of Rhino 3D at
no cost. So, if you want to get an idea of how it works, just go to
www.rhino3d.com<http://www.rhino3d.com/ and browse their site for the trial (and educational) copy.


Finally, two links to obtain an educational copy of SolidWorks are


http://www.journeyed.com/product/search?srch_cat=&qk_srch=solidworks<http://www.journeyed.com/product/search?srch_cat=&qk_srch=solidworks and


http://www.academicsuperstore.com/products/SolidWorks/SolidWorks?sourcecode<http://www.academicsuperstore.com/products/SolidWorks/SolidWorks?sourcecode=
lcg&promocode=0D8H00A1 .

Whatever you decide, good luck and happy hunting.

George Lazik
Santa Paula

I think one should start with something cheap as none of
them are real easy to learn. One could get real frustrated really
fast with Solid Works as it has a REAL STEEP learning curve.
One would then be out big bucks. But then again I might just
be an idiot :)

Solid Works also limits you year by year. You are just renting it.
While you really own Rhino. At least I do. They got this crappy
idea from Bill Gates.

BTW I have been using Rhino for at least 5 years doing hundreads if not
over a thousands designs and have never felt the need for the parametric
feature.

It does not help when doing aerodynamic shapes anyway
as you re-adjust the loft lines by dragging and re-loft.

Much better for airplanes and boats than SW IMHO.

SW is good but not worth the $3,000 more bucks initially and
rent for the rest of your life.

Paul Lamar


Dear Paul,
I use Solidworks. But the German made "One Design" CAD program is
much more intuitive in use. Particular when doing design modifications.
Dave Barker


Paul,
You guys have it wrong with SolidWorks. You own it once you buy it. The
annual fees are for updates and ongoing tech support. If you don't pay the
annual subscription, you just don't get the updates or the new versions when
they come out, but your serial number is licensed forever.
Are you getting new versions of Rhino every year with quarterly updates and
unlimited tech support for free?

Granted, the learning curve is steep, but the surfaces capability in
SolidWorks 2010 is outstanding for doing very complex shapes with very
smooth transitions.
If someone is willing to spend the time to learn solidworks, it is far more
powerful than the other systems out there at the same price.
I make my living designing, and if there was a more powerful system for less
money....... I would have found it.
I am sure Jarret will agree....

Larry

Linux is a bargain. Cost me $16 dollars and I am getting automatic updates
once a week. SW is way too rich for my blood :)

Paul Lamar