Radiance arch2rad program

ARCH2RAD(1)                                                        ARCH2RAD(1)

NAME

       arch2rad - convert Architrion text file to RADIANCE description

SYNOPSIS

       arch2rad [ -n ][ -m mapfile ] [ input ]

DESCRIPTION

       Arch2rad  converts an Architrion text file to a RADIANCE scene descrip-
       tion.  The material names for the surfaces will assigned based  on  the
       default  mapping  or  the mapping rules file given in the -m option.  A
       mapping file contains a list of materials followed by the conditions  a
       surface must satisfy in order to have that material.

       For  example,  if we wanted all surfaces for blocks with RefId "thingy"
       and Color 152 to use the material "wood", and all other surfaces to use
       the material "default", we would create the following mapping file:

            default ;
            wood (RefId "thingy") (Color 152) ;

       All  surfaces  would  satisfy  the  first  set  of conditions (which is
       empty), but only the surfaces in blocks with RefId "thingy"  and  Color
       152 would satisfy the second set of conditions.

       Each  rule  can  have  up to one condition per qualifier, and different
       translators use different qualifiers.  In arch2rad,  the  valid  quali-
       fiers are Layer, Color, Face and RefId.  A condition is either a single
       value for a specific attribute, or an integer range of values.   (Inte-
       ger  ranges  are  specified  in  brackets and separated by a colon, eg.
       [-15:27], and are always inclusive.)  A semicolon is used  to  indicate
       the end of a rule, which can extend over several lines if necessary.

       The  semantics  of the rule are such that "and" is the implied conjunc-
       tion between conditions.  Thus, it makes no sense to have more than one
       condition  in a rule for a given qualifier.  If the user wants the same
       material to be used for surfaces  that  satisfy  different  conditions,
       they  simply add more rules.  For example, if the user also wanted sur-
       faces in blocks with RefId "yohey" with Colors between 50  and  100  to
       use "wood", they would add the following rule to the end of the example
       above:

            wood (Color [50:100]) (RefId "yohey") ;

       Note that the order of conditions in a rule  is  irrelevant.   However,
       the  order  of  rules  is very important, since the last rule satisfied
       determines which material a surface is assigned.

       By convention, the identifier "void" is used to  delete  unwanted  sur-
       faces.  A surfaces is also deleted if it fails to match any rule.  Void
       is used in a rule as any other material,  but  it  has  the  effect  of
       excluding  all matching surfaces from the translator output.  For exam-
       ple, the following mapping would delete all surfaces  in  the  Layer  2
       except those with the color "beige", to which it would assign the mate-
       rial "beige_cloth", and all other surfaces would be "tacky":

            tacky ;
            void (Layer 2) ;
            beige_cloth (Layer 2) (Color "beige") ;

       If neither the -m nor the -n options are not used,  arch2rad  uses  the
       default mapping file "/usr/local/lib/ray/lib/arch.map".  This file sim-
       ply assigns materials  based  on  color,  using  the  identifiers  "c0"
       through  "c255".   Appropriate materials for these identifiers are con-
       tained in "/usr/local/lib/ray/lib/arch.mat".

       The -n option may be used to produce a list of qualifiers from which to
       construct a mapping for the given Architrion file.  If the -m option is
       used also, only those blocks matched in the mapping file will be  added
       to the qualifier list.

DETAILS

       Architrion  blocks  are  divided into about 6 polygons.  The reference,
       opposite and end faces must  all  be  quadrilaterals  (ie.   four-sided
       polygons), though one or more faces may disappear in certain degenerate
       cases.  The bottom face will usually be a quadrilateral, though it  may
       be written out as two triangles if the face is non-planar or one trian-
       gle if there is a degenerate side.  The top face is treated the same as
       the bottom face.

       Openings  are currently handled using the antimatter material type.  An
       antimatter material called "opening" is defined that "clips" all  faces
       for the current block, and patches the edges of the hole with the mate-
       rial defined for the face "sill".  If no rule is given specifically for
       the sill face, then the most specific material (ie. the material in the
       latest rule) for this block is used.  An antimatter  opening  will  not
       function  properly if there is another surface intersecting it, or ren-
       dering is attempted from within the opening.  Overlapping  openings  or
       openings  with shared boundaries will also fail.  There is currently no
       support of Architrion "frame" libraries.

       Naming of the output faces is based on layer number, reference  id  and
       output  block  number  (sequential from 1 to the total number of output
       blocks).  If there is no reference id name, the layer name is used  (if
       available)  instead  of  the  layer number.  If there is a reference id
       number but no name, that is added as well.  Names are truncated to  the
       first 12 characters, so the ends of long names may be lost.  Also, spa-
       ces in names are replaced by underscores ('_').  Finally, the  face  id
       is  added  to  the  end  of the block name for each output polygon.  An
       example identifier for a polygon is:

            l3.window_overh.3155.ref

       This would be the reference face of output block number 3155, reference
       id name "window overhangs" in layer number 3.

EXAMPLE

       To create a qualifier list for building.txt:

         arch2rad -n building.txt > building.qual

       To translate building.txt into a RADIANCE file using the mapping build-
       ing.map:

         arch2rad -m building.map building.txt > building.rad

       To create an octree directly from an Architrion file using the  default
       mapping and materials:

         oconv  source.rad  /usr/local/lib/ray/lib/arch.mat '\!arch2rad build-
         ing.txt' > building.oct

FILES

       /usr/local/lib/ray/lib/arch.map /usr/local/lib/ray/lib/arch.mat

AUTHOR

       Greg Ward

SEE ALSO

       ies2rad(1), oconv(1), thf2rad(1), xform(1)

RADIANCE                           11/15/93                        ARCH2RAD(1)