Re: CAD software?

From: Brock Hinzmann (SRI  International)
To: RP-ML
Date: Thursday, January 26, 1995
Subject: Re: CAD software?
David Roach asks: 
>>I am presently looking at the design component of a product which may 
require some Rapid Prototyping.  My question is "what CAD software 
would be best to use so that it can easily be handed over for rapid 
prototyping, if required?"
     
>From my understanding, 3D CAD files must be converted to "stl?" 
format for RP.  Are some CAD systems better than others?  Should 
files be created a certain way?  Does it make any difference?<<
     
I'll let others decide how they want to respond. It is easy to get into trouble 
recommending for or (especially) against a specific product in public. My 
understanding is the first step is that you should design in solids. Wireframe 
and surface models apparently cause lots of problems, especially in 
stereolithography. Solid modeling apparently results in a better .STL file and 
part from the RP machine. A survey of service bureaus done a few years ago 
indicated several packages that are popular, such as Pro/Engineer (PTC), 
AutoCAD, Concept Station (Aries), CADDS (Computervision), I-DEAS (SDRC), 
CADKEY, CATIA (Dassault), Unigraphics (EDS), CAMax, SolidDesigner (HP), Anvil 
(MCS), and EUCLID (Matra). Some others probably exist. Another evaluation I saw 
last year ranked four of these over the others, but stated that each of the 
top-ranked systems has its own problems. The ranking and the popularity don't 
match up, so you may want to check carefully with what your designers are 
using, what your service bureau would prefer, if you intend to use the same 
data for manufacturing as for product visualization and check with your 
manufacturing folks, how much money you have to spend, and so forth. 
     
Perhaps the rp-ml is a good place to take a survey on what the other users 
prefer. If you send me your votes, I will be happy to tally them. The rules 
should be that you vote on what you actually use, versus what you have heard. 
You may vote for more than one system, if you use more than one, and I will 
provide a vote tally plus a percentage of use among those voting (which will 
add to more than 100 percent). If we have enough votes, it might be 
interesting to show regional differences (N.A., Europe, Asia). This is more of 
a popularity contest than a ranking, so no need to give any qualitative 
comments. You may respond publicly or, if you prefer, privately. I promise not 
to reveal any confidences, although I think we should allow Geoff and others 
to publish the final talley in RPR and elsewhere (with proper citation, of 
course!).
     
Brock Hinzmann