rtcheck — Make UNIX-Plot of overlaps in an mged model, using raytracing


rtcheck [options...] model.g objects... > overlaps.plot3


rtcheck operates on the indicated objects in the input model.g and produces a floating point 3-D BRL-style plot3(5) format file on standard output, in millimeters.

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 the -s option. The -M option is most useful when rtcheck is being automatically invoked from within mged(1) using the rtcheck command in mged.

The following options are recognized.


The grid cell width, in millimeters. Ordinarily, the cell width is computed by dividing the view size by the number of pixels of width. This option provides an alternate direct means to set the grid cell width.


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


Report unique overlaps. At the end of a view, a list of unique pairs of overlapping regions is printed, along with a count of the number of detected overlaps for each pair. Not all detected overlap combinations are necessarily listed, as the overlap partition may mask a second overlap that is a continuation of an already detected overlap.


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


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


Sets the grid cell height, in millimeters.


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


Specify the maximum number of processors (in a multi-processor system) to be used for this execution. The default is 1.

-+ t

Specify that rtcheck should output plot file data in text format. Default is binary plot data.

rtcheck also accepts all other options that the rt(1) program implements, such as for non-square views, perspective, etc.

The rtcheck program is a simple front-end to librt(3) which is most useful when used from mged(1). The output can be independently viewed using the UNIX-plot viewers like plot3-fb(1), tplot(1), etc.


mged(1), rt(1), rtray(1), rtpp(1), plot3-fb(1), tplot(1), libplot3(3), librt(3), plot3(5)


Numerous error conditions are possible. Descriptive messages are printed on stderr (file descriptor 2).


Michael John Muuss

Gary S. Moss


This software is Copyright (c) 1988-2016 United States Government as represented by the U.S. Army Research Laboratory.


Most deficiencies observed while using the rtcheck program are a consequence of problems in librt.(3)


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