(registered 2018-03-06, last updated 2022-09-20)

Media type name: model

Media subtype name: stl

Required parameters: N/A

Optional parameters: N/A

Encoding considerations: binary

Security considerations: This media type does not allow for any kind 
   of executable content and is non-extensible. As such, the data 
   elements currently defined in the STL specification do not in 
   themselves create security risks beyond the information disclosed, 
   since the elements are not used to induce any behavior by the 
   recipient software application.

   This format doesn't itself provided any form of integrity or 
   confidentiality protection, so if such protection is needed it 
   must be done externally, e.g., through the use of HTTPs.

Interoperability considerations: The StereoLithography (STL) file 
   format is the lowest common denominator data format for exchange 
   of 3D models between different software systems. It is the one 
   file type almost assured to be supported by any given 3D modeling 
   / printing software application. Thus, supporting STL maximizes 
   interoperability when the capabilities of the recipient system is 
   unknown, and specific advanced 3D model features are not required.

   There are two variants of STL defined in the specification: ASCII 
   and binary. The binary format is more compact and thus more 
   commonly utilized by modern software systems creating STL files, 
   particularly those representing highly detailed objects. In common 
   use, no distinction is made in file type extension between the two 
   variants. Recipient systems thus routinely encounter and can parse 
   either variant. Therefore, this application proposes no 
   distinction.

Published specification: 3D Systems, Inc. 1989. StereoLithography 
   Interface Specification

Applications which use this media: This media type is used to 
   exchange 3D models intended for visualization and/or printing. The 
   data consists of sets of adjacent triangles that together define a 
   tessellated geometric surface. STL data would typically be created 
   by a 3D modeling software and then sent to a 3D print preparation 
   software. The latter program would produce 
   machine/materials-specific instructions for the 3D printing 
   device. In some cases, a 3rd piece of software (a visualizer) 
   would be used to preview and inspect the STL data prior to 
   submission to the print preparation software.

Fragment identifier considerations: This media type not fragmented. 
   As such, no media type specific fragment identifier or fragment 
   semantics are defined.

Restrictions on usage: None. 3D Systems allows payment-free use of 
   this format.

Additional information:

   1. Deprecated alias names for this type: N/A
   2. Magic number(s): N/A
   3. File extension(s): stl
   4. Macintosh file type code: N/A
   5. Object Identifiers: N/A

General Comments: This media type is intended to be referenced in 
   Supplement 205 (Encapsulation of STL 3D Models) of the DICOM 
   standard, currently under letter ballot. The intent is for this 
   supplement to be published in the June 2018 update of the standard.

   References:
   DICOM Standards Committee, "Digital Imaging and Communications in 
   Medicine (DICOM)", <http://dicom.nema.org/standard.html>.

   NOTE: The DICOM Standards Committee is an IESG recognized 
   organization. 
   https://www.iana.org/assignments/iesg-recognized-organizations/iesg-recognized-organizations.xhtml

Person to contact for further information:

   Name: Carolyn Hull
   Email: dicom&dicomstandard.org

   Name: Working Group 17 Chairs
   Email: wg17chairs&dicomstandard.org

Intended usage: Common

   Although being proposed due to the specific needs of medical 
   imaging, this media type would be useful in any 3D printing use 
   cases that require inter-application model exchange.

Author/Change controller: 

   DICOM Standard Committee
   dicom&dicomstandard.org