Re: History of .stl format

From: Joe Allison (
Date: Wed Jan 15 1997 - 19:05:42 EET

At 10:04 AM 1/15/97 -0500, you wrote:
>Hello all--
>Does anyone out there no what .stl stand for? How was it established as
>the format of choice among most RP equipment and CAD vendors? Who
>developed it? Who named it? etc.
>Reginald Ponder
>Laboratory Manager
>Rapid Prototyping & Manufacturing Institute
>Georgia Institute of Technology

1. STL stands for STereoLithography.

2. As the name would imply, it originated and established by 3D Systems,
Inc. of Valencia CA. The reason it has become the defacto standard is
because it was the first published interface specification for rapid
prototyping and it works. Others have been published since, but CAD vendors
don't like to write any more interfaces than absolutely necessary.

3. It was created in 1988 by Alberts Consulting Group under contract for 3D
Systems, Inc..

4. One of these to entities probably selected the suffix "STL".
Created in 1988 by Albert Consulting Group for 3D Systems, Inc.

5.(Etc.) Comes in two different versions - ASCII and binary. Binary is
preferred format for general use because it is more compact. The ASCII
format intended for diagnostic purposes for programmers and ambitious rapid
prototypers. For more information contact 3D Systems. Their web site is

Also, a breif but accurate description of the format is that it converts the
solid model surfaces into triangular planar facets with an orientation
vector to define the outside of the model. This format was selected because
almost all CAD systems already have faceting engines for the purpose of high
speed rendering and it lends itself well to cross sectioning algorithms.

Thats seems like enough trivia for one e-mail.

Joe Allison
Solid Concepts Inc.
Rapid Prototyping Software and Services
phone: (805) 257-9300
fax: (805) 257-9311

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