Jeroen,
I also received a similar e-mail from Materialise, whose Magics 6 does
something similar to what you are describing.
Yes, there is *room* in an StL file for color or other information, but
your inclusion of that information creates a new data format. In my message
yesterday, perhaps instead of saying that there is "no place" for color, I
should have said that there is no definition of color in the StL spec.
StL is a technical specification for a data format
(http://www.ennex.com/fabbers/StL.sht). If you include color or other
information in the file, you are creating an extension or modification of
the StL spec. If you publish the format that you use for this information
(or if enough other people reverse engineer it and adopt it), then it may
become a new standard. If you only use vacant data elements from the
original StL spec, then your new format should be downward compatible with
programs expecting plain StL files.
If TNO and Materialise do not intend to keep your StL extensions
proprietary, perhaps you'd like to post their definitions to the RP-ML. If
the way you represent color is different, then we're in for a little format
war.
Best regards,
Marshall Burns
President, Ennex Corporation
Marshall@Ennex.com
Los Angeles, USA, (310) 397-1314
http://www.Ennex.com
----- Original Message -----
From: <J.vandenHout@ind.tno.nl>
To: <Marshall@ennex.com>; <rp-ml@bart.lpt.fi>
Sent: Friday, November 17, 2000 06:50
Subject: RE: stl files
> Infact, there is space to store colour information in an STL file.
> We've succesfully used this 'STL Colour' format for some time now.
> The STL file remains an ordinary STL file. The (unused until now) 2 bytes
> that are included in each triangle store the colour information for each
> triangle.
>
> Of course there are some good alternatives like PLY and VRML, but
especially
> VRML is able to store a whole lot of other information that is not
relevant
> for RP systems and this increases the chances of errors during
dataexchange.
> Why not try to use the beauty of the simplicity of the STL file in the
> colour RP world?
>
> When colour RP is taken into a higher level, like texturemapping (as we're
> currently working on), more information is needed besides the triangles,
but
> even in this case STL can be used (by including the texture bitmap as a
> seperate file).
>
>
> Jeroen van den Hout
> TNO Institute of Industrial Technology
> Production Development Division
> Department of Industrial Prototyping
> P.O.Box 5073
> 2600 GB Delft
> The Netherlands
> Tel:+31-15-2608747 / +31 6 55514510
> Fax:+31-15-2608725
>
> Visit us at:
> http://www.ind.tno.nl/en/productiondevelopment/prototyping/index.html
> <http://www.tno.nl/instit/indus/prototyping/index.html>
>
>
> -----Oorspronkelijk bericht-----
> Van: Marshall Burns [SMTP:Marshall@Ennex.com]
> Verzonden: vrijdag 17 november 2000 14:01
> Aan: Doty Mike; NECOINC@aol.com; List: Rapid prototyping
> Onderwerp: Re: stl files
>
>
>
> You're right, Mike. Data redundancy is one of the criticisms of the
> StL
> format that leads many people to want to replace it. But a worse
> problem is
> that now with the advent of color fabbing (Z Corp. and TNO), StL
> provides no
> place for the color data. There are other problems too and StL is
> likely to
> be replaced in coming years with a better format.
>
> Best regards,
> Marshall Burns
> President, Ennex Corporation
>
> Marshall@Ennex.com
> Los Angeles, USA, (310) 397-1314
> http://www.Ennex.com
>
For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/
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