ARCH2RAD(1)						      General Commands Manual						       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 description.  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.
       (Integer  ranges are specified in brackets and separated by a colon, eg. [-15:27], and are always inclusive.)  A semicolon is used to indi-
       cate 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 conjunction 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 surfaces 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 surfaces.  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 example,
       the following mapping would delete all surfaces in the Layer 2 except those with the color "beige", to which it would assign  the  material
       "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/share/radiance/lib/arch.map".  This file
       simply assigns materials based on color, using the identifiers "c0" through "c255".  Appropriate materials for these identifiers  are  con-
       tained in "/usr/share/radiance/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 triangle 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 material defined for the face "sill".  If no rule is given specifi-
       cally for the sill face, then the most specific material (ie. the material in the latest rule) for this block is used.  An antimatter open-
       ing will not function properly if there is another surface intersecting it, or rendering 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,
       spaces 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 building.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/share/radiance/lib/arch.mat '!arch2rad building.txt' > building.oct

FILES

       /usr/share/radiance/lib/arch.map /usr/share/radiance/lib/arch.mat

AUTHOR

       Greg Ward

SEE ALSO

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

RADIANCE
							     11/15/93							       ARCH2RAD(1)