Dear friends,
I am happy to find an urge in the rp-ml group for an alternative to the STL
file
format. STL has served the RP community well, and now I feel, time has come
to
find an alternative file format, which can handle more than an approximated
geometry
model, probably we require to represent attributes beyond exact geometry.
NIST is doing some work in this area and has conducted two workshops in
this direction (1996 & 1997). Outcome of the workshops : Develop an ISO 10303
(STEP) based format.
A standard (format) can not be developed in isolation, and it has to
accepted by a
significant number of users, developers and thinkers. In this context, what
do you
feel about conducting a workshop sometimes next year. I would like to hear
your
views (Users, RP-Manufacturers, Process-developers, Universities,RP-service
providers
and others).
Thanks.
Amba
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Amba D. Bhatt
Guest Researcher,
At National Institute of Standards and Technology,
Manufacturing Systems Integration Division
Building 304, Room 06
Gaithersburg, MD 20899-8262
U.S.A.
Phone(w): (301) 975 4467 Fax(w): (301) 975 5118
email amba.bhatt@nist.gov alternate email abhatt@nist.gov
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>I agree about not extending the STL format. Redundancy of vertices alone
makes
>the files huge, difficult to debug and fix and creates problems like two
vertices
>being close but not the same due to round off errors.
>
>Use of floats may (??) be a limiting factor also. Most CAD software uses
doubles (8 bytes)
>and when writing floats for STL there has to be rounding off.
>
>I dont quite agree with using graphics based formats since there objective
is
>very different than RP community. Resolution doesnt always mean the same
thing in these
>two. VRML material properties have very little to do with RP material
characterstics
>that may be desired.
>
>So what am I suggesting... Perhaps a new standard and I know people roll
their eyes
>but some thing NIST (nat Inst of standards & tech) can spearhead with reps
from all
>the RP vendors and RP communities including academia. Yes standards are
painful
>and take some time to implement but they are not always bad. Look at
programming
>languages like C and C++. Even IGES - as many as critics there are of the
file format
>one is still thankful for it - for without it imagine data translation
headaches.
>
>It has to meet certain criteria and be open (yet not included the world to
drag it down
>and no body uses it). Things like build orientations, layer thicknesses
(variable),
>material properties they should be included.
>
>AR
>
>Dr. Anshuman Razdan
>Technical Director PRISM
>***************************************************************
>* Ph: (602) 965 5368 FAX: (602) 965 2910
>* Office: GWC 574 Email: razdan@asu.edu
>* Snail Mail: PRISM, MCode 5106 Az St. Univ, Tempe AZ 852815106
>* http://surdas.eas.asu.edu/~razdan
>***************************************************************
>
>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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