RE: CATIA-to-STL (was: IGES to STL)

From: karapatis nakis (nakis@icapmail.epfl.ch)
Date: Wed Mar 18 1998 - 15:34:48 EET


About this, I have had a student making his diploma projet over this
project. He compared .stl outputs from several major CAD systems, and
compared the parameters you can modify (chord length, etc...)

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Nakis Karapatis
Laboratory for Production Management and Processes - LGPP
ICAP
Swiss Federal Institute of Technology, Lausanne
CH 1015 Lausanne
Switzerland
tel. +41 21 693 3861
fax + 41 21 693 3509
gsm + 41 79 214 2206
nakis.karapatis@epfl.ch
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> -----Message d'origine----- > De: Stahlhut, Todd A. [SMTP:stahlht@indy.navy.mil] > Date: mercredi, 18. mars 1998 12:52 > : adatt@iitk.ernet.in; rp_send_mail > Objet: Re: CATIA-to-STL (was: IGES to STL) > > Actually, not all translators are created equal. Since each > translator > is written independently by each CAD company, to the STL file format > specification developed by 3D, they can vary greatly in how they > choose > to output it. These differences can range from too many triangles to > mismatched or missing triangles. How the accuracy of the file is > controlled can vary greatly also. One translator may use a chordal > tolerance value and an angle control value (Pro E), another may use a > non descript accuracy value that doesn't really relate to any real > feature on the part, while another may not give you any control at > all. > For example, a good translator would define a cube with 12 triangles. > Another may completely cover the part with tiny triangles and create a > large file. Hope this helps, Todd Stahlhut > ---------- > From: adatt@iitk.ernet.in > To: corcor@ibm.net > Cc: rp-ml@bart.lpt.fi > Subject: Re: CATIA-to-STL (was: IGES to STL) > Date: Wednesday, March 18, 1998 4:40AM > > I am unable to understand the line: "file was always small". As per my > understanding, the file size depends on the triangulation parameters, > so > it is independent of the translator used. Pl. correct me if I am > wrong. > > Regards. > A. D. Bhatt > > > > > This is a multi-part message in MIME format. > > --------------92C018A23C433917686AA18C > > Content-Type: text/plain; charset=us-ascii > > Content-Transfer-Encoding: 7bit > > > > Hello people, > > > > I have extensive experience with STL generation from CATIA. When > ever I > > received an STL file from CATIA the file was always small and easy > to > > process. Most of the files we generate from CATIA can be emailed. > I think > > you will find that the resolution chosen for your parts is way to > high to be > > producing such large files. Try a SAG value of 0.03 and "MAX size > of > > Triangles" of 200 (this will depend on the part). Solids and > volumes > convert > > extremely well. To convert a surface model it would be better to > join > all the > > faces together into a skin first. This eliminates the problems of > reversed > > normals and gaps. > > > > I hope this can help? > > > > Daniel Corcoran > > > > DAN DAVIS, RAPID PROTOTYPE wrote: > > > > > Brandon, Victor and all: > > > > > > I do have the v4.1.7 CATIA translator, but find that it creates > really, > > > really large STL files (i.e., a quarter scale, 10-spoke cast > aluminum > > > car wheel was over 7Mb). Do you find this also? > > > > > > I've heard that this was a problem at Chrysler in the past and > they > > > switched to the Brockware translator. I was wondering if this is > still > > > the case or is it that my engineers do not know what settings to > use for > > > the translation? > > > > > > Please keep in mind that I am not really a CAD expert -- I know > just > > > enough to get into trouble....... > > > > > > Regards, > > > > Dan Davis > > > > Division Head, RP&M > > > > Perusahaan Otomobil Nasional Berhad (PROTON) > > > Hicom Industrial Estate > > > Batu 3 PO Box 7100 > > > Shah Alam, Selangor D. E. > > > 40918 MALAYSIA > > > > +60 3 515-3906 direct line > > > > +60 3 515-2380 direct fax > > > > +60 12 277-5770 hand phone > > > > > > > > > > > > > > > > > > > > ---------- > > > > From: Brandon Jacobsen[SMTP:brandonj@eagledesign.com] > > > > Sent: Monday, 16 March, 1998 19:32 > > > > To: DAN DAVIS, RAPID PROTOTYPE > > > > Subject: Re: IGES to STL > > > > > > > > Dan, > > > > > > > > I am not familiar with brockware's CATIA to STL translator, but > we > > > > have done extensive work with the CATIA STL package > > > > available in v4r1.7 and up. It is a little costly but it is an > > > > excellent stl translator. The major advantage of the CATIA > > > > translator is that you are 99.99% guaranteed a good STL file if > you > > > > have a Volume or solid. And an offset function that takes > > > > a single stl of a skin and gives it thickness, which is great > for > > > > rapid tooling. If you have any questions please feel free > > > > to call. > > > > > > > > Brandon R. Jacobsen > > > > Eagle Design & Technology, Inc. > > > > phone: (616) 748-1022 > > > > fax: (616) 748-1032 > > > > > > > > "If one synchronized swimmer drowns, do the rest have to drown > too?" > > > > > > > > > > > > > > > ---------------------------------------------------------------------- > -- > > > > > > Part 1.2 Type: application/ms-tnef > > > Encoding: base64 > > > > > > > > --------------92C018A23C433917686AA18C > > Content-Type: text/x-vcard; charset=us-ascii; name="vcard.vcf" > > Content-Transfer-Encoding: 7bit > > Content-Description: Card for Daniel Corcoran > > Content-Disposition: attachment; filename="vcard.vcf" > > > > begin: vcard > > fn: Daniel Corcoran > > n: Corcoran;Daniel > > org: Concentric Asia Pacific > > email;internet: corcor@ibm.net > > title: Industry Specialist > > x-mozilla-cpt: ;0 > > x-mozilla-html: FALSE > > version: 2.1 > > end: vcard > > > > > > --------------92C018A23C433917686AA18C-- > > > > > > For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/ > > > > For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/ > > For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/

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