RFC 2077 (rfc2077) - Page 3 of 13

The Model Primary Content Type for Multipurpose Internet Mail Extensions

RFC 2077                Model Primary MIME Types            January 1997


      temporal units. This allows for differing elements to be combined
      non-arbitrarily.

   4. Models can be single objects or composed of a collection of
      objects.  These normally independent objects are arranged
      in a master/slave scenario so that one object acts as the
      reference, or primary object, which defines how the other
      objects interrelate and behave.  This allows for the creation
      of mathematical, physical, economic, behavioral, etc. models
      which typically are composed of different elements.  The key is
      in the description: these types describe how something
      "behaves"; contrasted to typical data types which describe
      how something "is".

      The inclusion of this "collective" system works similar to the
      Email system's multipart/related type which defines the actions
      of the individual parts.  Further specification of the model/*
      subtypes utilizing these properties is left to the subtype
      authors.

   With these assumptions:

   a. the default dimensionality will be spatial and temporal (but
      any are allowed).

   b. it is presumed that models will contain underlying structure
      which may or may not be immediately available to the
      user. (fluid dynamics vector fields, electromagnetic
      propagation, interrelated IGES dimensional specifiers, VRML
      materials and operators, etc.)

   c. it is assumed that basis set conversion between model domains
      is lossless.  The interpretation of the data may change but
      the specification will not.  i.e. convert the model of the
      U.S.A.  Gross Domestic Product into a VRML model and navigate
      it to explore the variances and interrelationships.  The model
      has many dimensions but also "passages" and "corridors"
      linking different parts of it.  A similar situation is true
      for meshes and CAD files. The key is identifying the basis set
      conversion which makes sense.

   d. models are grouped to assure LESS loss of information between
      the model subtypes than to subtypes of other primary
      types. (i.e.  converting a chemical model into an image is
      more lossy than concerting it into a VRML model).






Nelson, et. al.             Standards Track