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RTXRAY(1)			    BRL-CAD			     RTXRAY(1)

       rtxray -	compute	a pseudo X-Ray image of	a model.

       rtxray [options...] model.g objects...

       rtxray operates on the indicated	objects	in the input model.g and
       produces	a simulated X-Ray image. At present, all materials are treated
       as having the same density. The total path length of each ray through
       solid material is computed and the result is divided by the "viewsize"
       (the length of the diagonal of the bounding box of the model, which
       represents the longest possible path). This relative thickness is then
       converted to gray scale where black (1) is the greatest possible
       thickness, through white	(255) which represents a very thin region. The
       color 0 is reserved for rays which pass through no material at all.
       This provides good contrast for the object (which would not usually be
       the case	if 255 were chosen) and	allows the background to be easily

       Most models do not fill their bounding volume (a	box which just
       encloses	the model) so the "safe" scaling described above usually
       results in very low contrast (mostly white) objects. Because of this, a
       default contrast	boost of 2.0 is	applied	before the path	lengths	are
       converted to gray scale.	This value can be changed with the -A# flag.
       This value must 1.0 or greater. Larger values provide higher contrast
       but may result in clipping values to black (actually 1).

       The orientation of the rays to be fired may be specified	by the -a and
       -e options, in which case the model will	be autosized, and the grid
       will be centered	on the centroid	of the model, with ray spacing chosen
       to span the entire set of objects. Alternatively, with the -M option, a
       transformation matrix may be provided on	standard input which maps
       model-space to view-space. In this case,	the grid ranges	from -1.0 <=
       X,Y <= +1.0 in view space, with the size	of the grid (number of rays
       fired) specified	with -s. This option is	most useful when rtxray	is
       being invoked from a shell script created by an mged(1) saveview

       The following options are recognized.

	   Number of rays to fire in X and Y directions	(square	grid). Default
	   is 512 (512x512).

	   Select azimuth in degrees. Used with	-e and conflicts with -M

	   Select elevation in degrees.	Used with -a and conflicts with	-M

	   Read	model2view matrix from standard	input. Conflicts with -a and

	   Contrast enhance the	output image by	the given factor. Default
	   value is 2.0. See discussion	above.

       -o specifies a named BW(5) file for output. By default, the
	   output is displayed on a frame buffer.

	   use the alternate "lighting model". In this mode, double precision
	   floating point numbers are written (-o must be used). Each number
	   is the actual solid material	path length for	that ray. This allows
	   for post processing and scaling.

       See the rt manual page for additional arguments that can	be used	with
       this program.

       rt(1), rtray(1)

       This program should do something	about material properties (X-Ray
       density)	in order to provide a more realistic result.

       Phillip Dykstra

       This software is	Copyright (c) 1990-2019	United States Government as
       represented by the U.S. Army Research Laboratory.

       Reports of bugs or problems should be submitted via electronic mail to

BRL-CAD				  08/29/2020			     RTXRAY(1)


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