I don't know how directly it does it, but I know that it is an
improvement on the normal chordal accuracy value you specify. My
understanding is that for small radii, where the chordal tolerance that
is acceptable for a larger radius would yield more faceting, the angular
value sets how much it will vary from the normal value. Do watch in
some earlier versions of pro 18, there is a 'bug' in the STL formatter
that yields very bad faceting. I suggest you contact Pro E. I run Pro
E 18, version 4750 and it seems to fix it. If you have a older version
and you see large flats on your builds where you should see radii, set
your angular tolerance to zero.
Hope this helps. Todd Stahlhut
----------
From: Totong Kaya
To: Stahlhut, Todd A.
Subject: Re: CATIA-to-STL (was: IGES to STL)
Date: Friday, March 20, 1998 8:48PM
Hi Todd
Do you know how the angle control value defines the accuracy of the STL
file in Pro/ENGINEER?
Thanks
Rgds
Kaya
---
On Wed, 18 Mar 1998, Stahlhut, Todd A. wrote:
> 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?"
> > > >
> > > >
> > >
> > >
------------------------------------------------------------------------
> > >
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> > > Encoding: base64
> >
> >
> >
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> > 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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