Die STL.die

From: Ismo Mäkelä (Makela@deskartes.fi)
Date: Tue Dec 21 1999 - 10:13:37 EET

Dear Mr. Scott and rp-ml,

The discussion about the usefulness of the stl-format
has been a very interesting one. Here at DeskArtes
we have taken another way to avoid the problems
caused by the usage of triangles.

The accuracy of the result decreases when a faceting step
is needed between the surface model and the slices. This can
be minimized by doing the slicing directly on the surface
model. The user supplies the slice thickness and the maximum
deviation of the slice segments from the original surface.
The result is a smooth looking set of curves following
nicely the original surface. Also, you do not see the typical
triangle pattern on your slice data.

This is a new product. The direct slicing functionality is
available in the latest version 4.2 of DeskArtes Rapid Tools sw.
It runs on Unix and Windows NT. Rapid Tools can
input IGES or VDA surface data and output slices in
IGES, VDA, CLI, SLI, SSL and SLC formats.

We would be very happy to co-operate if somebody is interested
to do some tests with the direct slicing.

Best regards,

Ismo Mäkelä,
DeskArtes Oy

P.S. Please have a look at our web pages at

ATiburon@aol.com wrote:
> In a message dated 99-12-16 14:11:02 EST, gfadel@ces.clemson.edu writes:
> << One advantage I saw mentioned by Stephen Rock in the exchanges is
> that slicing would be much faster - say 2 to 3 times faster on the average.
> Would that be good enough a reason to migrate? >>
> The major drawback to STL is the FACET. The STL is great for describing
> boxes. But really sucks for curved surfaces, small radii, internal
> passageways etc. It's ludicrous in the extreme for RP manufacterers to be
> claiming .001 in plane accuracies when the file format won't come that close.
> Not with a zillion triangles! There have been formats already that did
> perform better when used on curved models, things like Cars, Airplanes,
> barbie dolls, etc. One is CATSLICE, available for Catia only I believe, I
> don't know if it is still supported. The other was the approach as by Fockle
> and Schwatrz, and perhaps a few others to use HPGL slices, supported by
> Magics etc. The STL is the major impediment for RP's progression/evolvement
> into RM (rapid manufacturing). Accuracy, surface finish and utlity all suffer
> because STL will never be more than just an approximation. That is OK perhaps
> for many models, but totally inadiquate for tooling or production.
> Andy Scott
> Lockheed Martin Aero Sys
> 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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